BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Marta Marchese (Queen's University Belfast) DTSTART:20201007T130000Z DTEND:20201007T140000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/1 DESCRIPTION:Title: Hypothesis testing for fundamental physics\nby Marta Marchese (Queen's University Belfast) as part of UniKORN seminars\n\n\nAbstract\nQu antum hypothesis testing\, \nfirst introduced for quantum state discrimina tion\, has found interesting applications in quantum channels and dynamics . Here\, we employ a variant of the test to ascertain if an optomechanical system is subject to a possibly unknown decoherence mechanism. In particu lar\, our goal is to see if using quantum resources provides an advantage in channel discrimination. Our system is made of two cavities\, one equipp ed with a movable mirror\, initially pumped with only coherent light until reaching a steady-state configuration. At the beginning of the protocol\, we can additionally pump the cavities with an extra two-mode light chosen in an appropriate state. Two cases are examined\, according to the choice of the noise and output measurements: i) classical scenario\, in which we use two independent thermal modes and we perform local measurements\; ii) quantum scenario\, in which we inject the cavities with two-mode squeezed light and we measure EPR-like quadratures. A standard $\\chi^2$-test is c onducted to test the two possible hypotheses on the dynamics\, namely the presence or absence of the unknown decoherence mechanism\, that we chose t o be of the continuous spontaneous localization (CSL) type. We show how tw o-mode squeezing appears to offer a dynamical advantage in the channel dis crimination.\n\nThis talk is chaired and curated by Sofia Qvarfort.\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/1/ END:VEVENT BEGIN:VEVENT SUMMARY:Benjamin A. Stickler (University of Duisburg-Essen) DTSTART:20201021T130000Z DTEND:20201021T140000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/2 DESCRIPTION:Title: Quantum rotations in levitated optomechanics\nby Benjamin A. S tickler (University of Duisburg-Essen) as part of UniKORN seminars\n\n\nAb stract\nThe non-linearity and anharmonicity of rigid body rotations gives rise to pronounced quantum interference effects with no analogue in the bo dy's centre-of-mass motion. This talk will briefly review two such effects \, orientational quantum revivals [1] and the quantum tennis racket effect [2]\, and discuss how elliptic coherent scattering cooling [3] opens the door to rotational quantum experiments with nanoscale particles. I will al so report on our recent study of controlling the rotational motion of char ged nanoparticles in electric quadrupole traps [4].\n\n[1] Stickler\, Pape ndell\, Kuhn\, Millen\, Arndt\, and Hornberger\, New J. Phys. 20\, 122001 (2018).
\n[2] Ma\, Khosla\, Stickler\, and Kim\, Phys. Rev. Lett. 125\, 053604 (2020).
\n[3] Schäfer\, Rudolph\, Hornberger\, and Stickler\, arXiv: 2006.04090 (2020).
\n[4] Martinetz\, Hornberger\, Millen\, Kim\, and Stickler\, arXiv: 2005.14006 (2020).\n\nChaired by Sofia Qvarfort.\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/2/ END:VEVENT BEGIN:VEVENT SUMMARY:Giles Hammond (University of Glasgow) DTSTART:20201028T140000Z DTEND:20201028T150000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/3 DESCRIPTION:Title: Gravitational Wave Detection\nby Giles Hammond (University of Glasgow) as part of UniKORN seminars\n\n\nAbstract\nThe Laser Interferomet er Gravitational Wave observatory comprises two detectors located in Hanfo rd\, WA and Livinsgton LA. These detectors are 4km long Fabry-Perot Michel son interferometers and the most sensitive length measuring devices in the world. They are able to sense a change equivalent to 1/1000th the diamete r of a proton over their 4km baseline. The interferometers utilise a 1064n m Nd-YAG laser to illuminate the cavity mirrors. The mirrors are operated as free test masses\, requiring multiple stage pendulum suspensions and in ertial seismic isolation to ensure that seismic noise does not limit the d etector sensitivity. The final stage of the suspension is fabricated entir ely from fused silica to ensure that thermal noise does not limit their se nsitivity.\n\nIn this talk I will describe the technology development nece ssary to realise the LIGO detectors\, and also describe the broad range of gravitational wave signals that have been observed during observing runs 1-3. I will provide some insight into the astrophysics which can be gained from these “dark systems”\, only observable by listening to the Unive rse\, and provide an outlook on future detectors which could operate under ground and at low temperature.\n\nThis talk will be chaired by Prof Sheila Rowan.\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/3/ END:VEVENT BEGIN:VEVENT SUMMARY:Hannah McAleese (Queen's University Belfast) DTSTART:20201104T140000Z DTEND:20201104T150000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/4 DESCRIPTION:Title: Macroscopic quantumness of optically conditioned mechanical system s\nby Hannah McAleese (Queen's University Belfast) as part of UniKORN seminars\n\n\nAbstract\nIn optomechanical systems\, conditional measuremen ts on the optical mode can be used to engineer states of the mechanical mo de. In this talk\, I will discuss the effect that measurement settings hav e on the macroscopic quantumness of the mechanical mode. The measure used is based on phase-space methods (Phys. Rev. Lett. 106\, 220401 (2011)). Th e aim of the project is to find protocols which optimise mechanical macros copicity. Additionally\, I evaluate the effect of losses for the case of a n open cavity and analyze the impact on the features of the Wigner functio n of the mechanical state.\n\nChaired by Muddassar Rashid.\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/4/ END:VEVENT BEGIN:VEVENT SUMMARY:Montserrat Calleja (Micro and Nanotechnology Institute at CSIC) DTSTART:20201118T140000Z DTEND:20201118T150000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/5 DESCRIPTION:Title: Biosensors based on optonanomechanical systems\nby Montserrat Calleja (Micro and Nanotechnology Institute at CSIC) as part of UniKORN se minars\n\n\nAbstract\nI will present work performed in collaboration with Alberto Martín-Pérez\, Sergio García-López\, Marina L Yubero\, Adrián Sanz\, Javier E Escobar\, Juan Molina\, Oscar Malvar\, Priscila M Kosaka\ , Daniel Ramos\, Eduardo Gil-Santos\, Jose J Ruz\, Álvaro San Paulo\, Jav ier Tamayo from the Bionanomechanics group at Instituto de Micro y Nanotec nología\, IMN-CNM (CSIC).\nWe will be discussing the application of optom echanics to biology and biomedicine\, as well as how strategies inspired b y these phenomena can be applied to microscale devices for cancer cell cha racterization\, for the detection of attogram per mililliter concentration s of protein biomarkers in the exploration of the deep plasma proteome and for the identification of pathogens through their intrinsic mechanical pr operties. \n\n[1] Biosensors based on nanomechanical systems\, J Tamayo at al\, Chemical Society Reviews 42 (3)\, 1287 (2013)\n[2]Mass and stiffness spectrometry of nanoparticles and whole intact bacteria by multimode nano mechanical resonators\nO Malvar\, JJ Ruz\, PM Kosaka\, CM Domínguez\, E G il-Santos\, M Calleja\, J Tamayo\, Nature communications 7\, 13452 (2016)\ n[3]Silicon nanowires: where mechanics and optics meet at the nanoscale\, D Ramos\, E Gil-Santos\, O Malvar\, JM Llorens\, V Pini\, A San Paulo\, M Calleja\, J Tamayo\, Scientific reports 3\, 3445 (2013)\n[4] Optomechanics with silicon nanowires by harnessing confined electromagnetic modes\, D R amos\, E Gil-Santos\, V Pini\, JM Llorens\, M Fernández-Regúlez\, A San Paulo\, M Calleja\, J Tamayo\, Nano letters 12 (2)\, 932-937 (2012)\n[5]Me chano-optical analysis of single cells with transparent microcapillary res onators\, A Martín-Pérez\, D Ramos\, E Gil-Santos\, S García-López\, M L Yubero\, PM Kosaka\, A San Paulo\, J Tamayo\, M Calleja\, ACS sensors 4 (12)\, 3325-3332\, 2019\n [6]Detection of cancer biomarkers in serum using a hybrid mechanical and optoplasmonic nanosensor\, PM Kosaka\, V Pini\, J J Ruz\, RA Da Silva\, MU González\, D Ramos\, M Calleja\, J Tamayo\, Natu re nanotechnology 9 (12)\, 1047 (2014)\n [7]Optomechanical devices for dee p plasma cancer proteomics\, PM Kosaka\, M Calleja\, J Tamayo\, Seminars i n cancer biology 52\, 26-38 (2018)\n [8] Gil-Santos\, E.\, Ruz\, J.J.\, Ma lvar\, O. et al. Optomechanical detection of vibration modes of a single b acterium. Nat. Nanotechnol. 15\, 469–474 (2020). https://doi.org/10.1038 /s41565-020-0672-y\n [9] Juan Molina\, Daniel Ramos\, Eduardo Gil-Santos\, Javier E. Escobar\, José J. Ruz\, Javier Tamayo\, Álvaro San Paulo\, an d Montserrat Calleja. Optical Transduction for Vertical Nanowire Resonator s. Nano Letters 2020 20 (4)\, 2359-2369. DOI: 10.1021/acs.nanolett.9b04909 \n\nChaired by Alexandra Olaya-Castro\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/5/ END:VEVENT BEGIN:VEVENT SUMMARY:Jack Clarke (Imperial College London) DTSTART:20201125T140000Z DTEND:20201125T150000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/6 DESCRIPTION:Title: Creating quantum states of mechanical motion via pulsed optomechan ics\nby Jack Clarke (Imperial College London) as part of UniKORN semin ars\n\n\nAbstract\nCavity quantum optomechanics utilizes the radiation-pre ssure interaction between light and a moveable mechanical object inside a cavity for applied and fundamental physics. When combined with the tools o f quantum optics\, optomechanics provides a route for engineering non-clas sical states of motion in a more macroscopic regime. We explore the pulsed regime of cavity quantum optomechanics\, which utilizes pulses of light m uch shorter than a mechanical period\, for mechanical quantum state engine ering applications. In particular\, we propose protocols for preparing mec hanical superposition states [1] and entanglement between two massive osci llators [2]. \n\n[1] Jack Clarke and Michael R Vanner\, Quantum Sci. Techn ol. 4\, 014003 (2019)\n\n[2] Jack Clarke et al.\, New J. Phys. 22\, 063001 (2020)\n\nChaired by Markus Rademacher.\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/6/ END:VEVENT BEGIN:VEVENT SUMMARY:Antonio Pontin (University College London) DTSTART:20201202T140000Z DTEND:20201202T150000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/7 DESCRIPTION:Title: Quadratic optomechanical cooling of a cavity-levitated nanosphere. \nby Antonio Pontin (University College London) as part of UniKORN sem inars\n\n\nAbstract\nThe optomechanics field has shown tremendous advancem ents in the last couples of decades\, making an impact in both application s and foundational physics. Recently\, a new platform has been gathering m omentum. This is the field of levitated optomechanics where a nanoparticle can be trapped and manipulated in isolation from the environment by optic al\, magnetic or electric fields.\n\nIn this talk I will present our recen t results based on the levitation of a highly charged silica nanoparticle in a hybrid potential composed of a linear Paul trap and the standing wave of a high finesse cavity. With this system we were able to demonstrate co oling of the particle motion exclusively due to a coupling to the light wh ich is quadratic in displacement. This is the first demonstration of a dyn amic dominated by such coupling across all optomechanical systems.\n\nChai red by Muddassar Rashid.\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/7/ END:VEVENT BEGIN:VEVENT SUMMARY:Gabriel Hetet (Laboratoire de Physique de l'ENS) DTSTART:20201209T140000Z DTEND:20201209T150000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/8 DESCRIPTION:Title: Spin-mechanics with levitating diamonds\nby Gabriel Hetet (Lab oratoire de Physique de l'ENS) as part of UniKORN seminars\n\n\nAbstract\n Observing and controlling macroscopic quantum systems has long been a driv ing force in research on quantum physics. The angular degrees of freedom o f levitating diamonds coupled to embedded NV centers offer bright prospect s towards this purpose. \n\nIn this talk I will present our recent results in this direction : our observations of spin-dependent torque and spin-co oling of the diamond angular motion as well as our mechanical detection of dipolar interactions.\n\nChaired by James Millen.\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/8/ END:VEVENT BEGIN:VEVENT SUMMARY:Markus Aspelmeyer (University of Vienna) DTSTART:20200714T130000Z DTEND:20200714T140000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/10 DESCRIPTION:Title: Quantum optical control of levitated solids: a fresh perspectives on the gravity-quantum interface\nby Markus Aspelmeyer (University of Vienna) as part of UniKORN seminars\n\n\nAbstract\nThe increasing level o f control over motional quantum states of massive\, solid-state mechanical devices opens the door to an hitherto unexplored parameter regime of macr oscopic quantum physics. I will report on our recent progress towards cont rolling levitated solids in the quantum regime. I will discuss the prospec ts of using these systems for fundamental tests of physics\, including the interface between quantum and gravitational physics.\n\nRecorded talk ava ilable upon email request.\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/10/ END:VEVENT BEGIN:VEVENT SUMMARY:Marko Toroš (University College London) DTSTART:20200722T130000Z DTEND:20200722T140000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/11 DESCRIPTION:Title: Quantum sensing and cooling in three-dimensional levitated cavity optomechanics\nby Marko Toroš (University College London) as part of UniKORN seminars\n\n\nAbstract\nA recent experimental breakthrough has pr opelled levitated optomechanics into the quantum domain [1]. The new coher ent scattering (CS) setup has the capability to prepare highly non-classic al states for nano-sized objects\, opening the possibility to explore unpr obed quantum mechanical regimes. We will briefly review the main features of the CS setup and highlight some of its novel 3D aspects such as the hyb ridization of the mechanical modes and the backaction effects [2]. We will conclude by a few remarks on possible applications such as testing gravit ational effects in Quantum mechanics [3].\n\n[1] Delić U\, Reisenbauer M\ , Dare K\, Grass D\, Vuletić V\, Kiesel N\, Aspelmeyer M. Cooling of a le vitated nanoparticle to the motional quantum ground state. Science. 2020 F eb 21\;367(6480):892-5.\n\n[2] Toroš\, M. and Monteiro\, T.S.\, 2020. Qua ntum sensing and cooling in three-dimensional levitated cavity optomechani cs. Physical Review Research\, 2(2)\, p.023228.\n\n[3] Bose\, S.\, Mazumda r\, A.\, Morley\, G.W.\, Ulbricht\, H.\, Toroš\, M.\, Paternostro\, M.\, Geraci\, A.A.\, Barker\, P.F.\, Kim\, M.S. and Milburn\, G.\, 2017. Spin e ntanglement witness for quantum gravity. Phys. Rev. Lett. 119(24)\, p.2404 01.\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/11/ END:VEVENT BEGIN:VEVENT SUMMARY:Georg Enzian (University of Copenhagen) DTSTART:20200729T130000Z DTEND:20200729T140000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/12 DESCRIPTION:Title: Brillouin cavity optomechanics with whispering-gallery microreson ators\nby Georg Enzian (University of Copenhagen) as part of UniKORN s eminars\n\n\nAbstract\nCavity quantum optomechanics uses fields of light t o generate and study quantum states of motion of macroscopic mechanical re sonators and is one of the newest and most rapidly growing areas of quantu m optics. Excitingly\, the field pursues several different experimental di rections including Fabry-Perot cavities with movable mirrors\, levitated o ptomechanical systems\, and other nano-optical implementations\, each havi ng their own advantages and disadvantages. In this talk\, a new direction – Brillouin optomechanics – will be discussed\, which unites several f avourable properties including very high mechanical frequencies (> 10 GHz) \, very low optical loss and absorption\, and back-scatter operation to al low the signal to be easily separated from the pump. Using a silica micro- resonator\, we have experimentally observed Brillouin optomechanical stron g coupling between the optical cavity field and these high-frequency mecha nical vibrations [Optica 6\, 7 (2019)]. Additionally\, I will discuss a re cent experiment performing single-phonon addition and subtraction to a mec hanical thermal state of the acoustic whispering-gallery wave [arXiv:2006. 11599]. This research opens a rich avenue for further studies that test th e very foundations of quantum mechanics and the development of powerful ne w quantum technologies.\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/12/ END:VEVENT BEGIN:VEVENT SUMMARY:Alessio Belenchia (Queen's University Belfast) DTSTART:20200805T130000Z DTEND:20200805T140000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/13 DESCRIPTION:Title: Optomechanics meets Thermodynamics: Experimental assessment of en tropy production in a continuously measured mechanical resonator\nby A lessio Belenchia (Queen's University Belfast) as part of UniKORN seminars\ n\n\nAbstract\nThe information on a quantum process acquired through measu rements plays a crucial role in the determination of its non-equilibrium t hermodynamic properties. In this talk\, we report on the experimental infe rence of the stochastic entropy production rate for a continuously monitor ed mesoscopic quantum system. We consider an optomechanical system subject ed to continuous displacement Gaussian measurements and characterise the e ntropy production rate of the individual trajectories followed by the syst em in its stochastic dynamics. Owing to the specific regime of our experim ent\, we are able to single out the informational contribution to the entr opy production arising from conditioning the state on the measurement outc omes. This experiment embodies a significant step towards the demonstratio n of full-scale control of fundamental thermodynamic processes at the meso scopic quantum scale.\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/13/ END:VEVENT BEGIN:VEVENT SUMMARY:Laure Mercier de Lépinay (Aalto University) DTSTART:20200812T130000Z DTEND:20200812T140000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/14 DESCRIPTION:Title: Optomechanical nonreciprocal refrigerator\nby Laure Mercier d e Lépinay (Aalto University) as part of UniKORN seminars\n\n\nAbstract\nC avity optomechanics has successfully proposed inventive cooling techniques for mechanical oscillators\, allowing to bring phononic occupations of ma croscopic motion modes below unity. On the other hand\, in the past few ye ars\, mechanically-mediated\, nonreciprocal coupling of electromagnetic ca vities has been extensively studied as a means to engineer directional pro pagation of signal and noise. Interestingly\, the directional propagation of noise between mechanical oscillators can be expected to propose a novel cooling mechanism based on nonreciprocal coupling of mechanical oscillato rs. Ref [1] published in 2019 gave an experimental study of the impact of nonreciprocal coupling of a pair of membrane modes on their phononic occup ancies. We propose interpretations of the observed signatures\, and show t hat different simultaneous cooling mechanisms coexist. We show that one am ong these can indeed be identified as nonreciprocal cooling. Its impact mu st however be carefully distinguished from the other cooling mechanisms’ \, for which we propose an experimental method. The method is carried out experimentally on a pair of drum resonators in optomechanical coupling wit h a microwave cavity. We discuss the nature of the stationary state genera ted in such nonreciprocally-coupled systems\, and show that a quantum limi t exists to the novel nonreciprocal cooling mechanism\, which emerges in o ur experimental setup thanks to operation at low phonon numbers. Obtaining reduced phononic occupancies requires work from the experimentalist to br ing the system out of equiblibrium\, which makes the system analogous to a refrigerator functioning at low phonon numbers.\n\n[1] H. Xu\, L. Jiang\, A. A. Clerk and J. G. E. Harris\, “Nonreciprocal control and cooling of phonon modes in an optomechanical system”\, Nature\, vol. 568 p.65\, 20 19\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/14/ END:VEVENT BEGIN:VEVENT SUMMARY:Natalia Ares (University of Oxford) DTSTART:20200819T130000Z DTEND:20200819T140000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/15 DESCRIPTION:Title: Circuit optomechanics for thermodynamics at the nanoscale\nby Natalia Ares (University of Oxford) as part of UniKORN seminars\n\n\nAbst ract\nThe laws of thermodynamics are physics’ most solid pillar\, govern ing everything from black holes to the evolution of life. Rapid breakthrou ghs in optomechanics are now presenting us with the opportunity to test th ese laws in a completely new realm\, where fluctuations are important and quantum effects might arise. I will show you how we can explore thermodyna mics in this limit by probing the displacement of a nanomechanical resonat or. I will discuss the potential of optomechanical systems to pave the way for experiments on quantum information thermodynamics\, in particular\, f or revealing the thermodynamic costs of quantum operations.\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/15/ END:VEVENT BEGIN:VEVENT SUMMARY:Daniel Goldwater (University of Nottingham) DTSTART:20200902T130000Z DTEND:20200902T140000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/16 DESCRIPTION:Title: A Quantum Spectrometer for Arbitrary Noise\nby Daniel Goldwat er (University of Nottingham) as part of UniKORN seminars\n\n\nAbstract\nT his talk will report on and explain a recent proposal [PRL\, 2019] for a q uantum spectrometer. This equates to a technique for recovering the spectr um of a non-Markovian bosonic bath coupled to a harmonic oscillator\; a te chnique which is valid under the conditions that the environment is large and hot compared to the oscillator\, and that its temporal autocorrelation functions are symmetric with respect to time translation and reflection ( fairly minimal criteria). Since our proposal doesn’t rely on dynamically decoupling qubits\, and rather works with any quantum harmonic oscillator \, it could be used to probe collapse models with non-white noises. The ta lk will explain the spectrometer itself\, and expand on possible applicati ons in quantum foundations.\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/16/ END:VEVENT BEGIN:VEVENT SUMMARY:Anna Pearson (University of Oxford) DTSTART:20200909T130000Z DTEND:20200909T140000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/17 DESCRIPTION:Title: Measuring the thermodynamic cost of timekeeping with a radio-freq uency optomechanical system.\nby Anna Pearson (University of Oxford) a s part of UniKORN seminars\n\n\nAbstract\nThis talk will discuss a radio-f requency optomechanical experiment that has explored the thermodynamic cos t of timekeeping (arXiv: 2006.08670). The evolution of nature towards high er entropy states is used by clocks to quantify the passage of time. A min imal model for an autonomous quantum clock in the quantum realm has shown that within a certain regime an increase in entropy linearly increases the accuracy of quantum clocks. (Phys. Rev. X 7\, 031022 (2017)) We derive a theoretical bound for our classical clock\, which consists of a silicon n itride membrane capacitively coupled to a radio-frequency cavity (Sci. Rep . 10\, 1654 (2020)) . The bound shows that the accuracy of the classical c lock is also proportional to the entropy created per tick\, but with a dif ferent proportionality constant to the quantum case. Experimentally we fi nd that there is a linear relationship between the clock’s accuracy and its entropy production\, and that our experiment operates within an order of magnitude of the theoretical bound.\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/17/ END:VEVENT BEGIN:VEVENT SUMMARY:Jack Harris (Yale University) DTSTART:20200916T130000Z DTEND:20200916T140000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/18 DESCRIPTION:Title: Single phonon quantum acoustics with superfluid helium\nby Ja ck Harris (Yale University) as part of UniKORN seminars\n\n\nAbstract\nQua ntum effects in acoustic degrees of freedom offer exciting opportunities i n sensing\, control\, and information processing\, as well as in studies o f fundamental physics. To date\, much progress in this field has been made with systems whose dynamics is essentially linear (this includes the real ization of acoustic oscillators in their ground state or in squeezed state s\, and the observation of entanglement among acoustic and electromagnetic modes). However\, these systems’ linearity precludes access to “stron ger” quantum effects that would offer true performance enhancement and t ests of quantum mechanics in new regimes. One route to realizing nonlinear quantum acoustics is based on the back-action of single photon detectors. In this talk\, I will describe our use of this approach to detect and con trol individual phonons in a nanogram-scale body of superfluid helium. I w ill also described the future prospects of superfluid-based quantum acoust ic systems.\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/18/ END:VEVENT BEGIN:VEVENT SUMMARY:Yue Ma (Imperial College London) DTSTART:20200923T130000Z DTEND:20200923T140000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/19 DESCRIPTION:Title: Quantum Persistent Tennis Racket Dynamics of Nanorotors\nby Y ue Ma (Imperial College London) as part of UniKORN seminars\n\n\nAbstract\ nClassical tennis racket effect refers to the instability of mid-axis rota tion of an asymmetric rigid rotor. The flipping period of the mid-axis ori entation sensitively depends on the initial energy. Once averaged over a t hermal ensemble\, the flipping rapidly decays. However\, the situation is completely different in the quantum regime. Classically forbidden tunnelli ng and reflection near the separatrix redistribute the energy eigenvalues\ , therefore changing the distribution of mid-axis flipping frequencies. In a rapidly spinning quantum asymmetric rotor\, the mid-axis flipping persi sts much longer than the classical case\, even when millions of angular mo mentum states are occupied. The persistent flipping is expected to be obse rvable in nanoparticles or molecules when combining state-of-the-art techn ologies. [10.1103/PhysRevLett.125.053604]\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/19/ END:VEVENT BEGIN:VEVENT SUMMARY:Benjamin A. Stickler (University of Duisburg-Essen) DTSTART:20210111T100000Z DTEND:20210111T113000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/20 DESCRIPTION:Title: Lecture series: Decoherence in Macroscopic Quantum Systems\nb y Benjamin A. Stickler (University of Duisburg-Essen) as part of UniKORN s eminars\n\n\nAbstract\nSession 1: Introduction & Basics of Open Quantum Sy stems\n\nSession topics:\n\n\nLectu re series abstract:\n\nWhile the Schrödinger equation describes the dynam ics of isolated quantum systems\, real-world systems are always in contact with ambient environments. This leads to thermalisation as well as to dec oherence\, which can explain the emergence of classical behaviour for obje cts of increasing size and complexity. This short lecture series will prov ide the general framework to quantitatively describe the dynamics of open quantum systems and apply it to several practically relevant situations. A mongst others\, we will explore the role of decoherence in macroscopic mat ter-wave interference experiments and discuss the influence of the environ ment in quantum optomechanics.\n\nA recorded version of the lecture series is available upon email reques t.\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/20/ END:VEVENT BEGIN:VEVENT SUMMARY:Benjamin A. Stickler (University of Duisburg-Essen) DTSTART:20210112T100000Z DTEND:20210112T113000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/21 DESCRIPTION:Title: Lecture series: Decoherence in Macroscopic Quantum Systems\nb y Benjamin A. Stickler (University of Duisburg-Essen) as part of UniKORN s eminars\n\n\nAbstract\nSession 2: The Monitoring approach\n\nSession topic s:\n\n\n\nLe cture series abstract:\n\nWhile the Schrödinger equation describes the dy namics of isolated quantum systems\, real-world systems are always in cont act with ambient environments. This leads to thermalisation as well as to decoherence\, which can explain the emergence of classical behaviour for o bjects of increasing size and complexity. This short lecture series will p rovide the general framework to quantitatively describe the dynamics of op en quantum systems and apply it to several practically relevant situations . Amongst others\, we will explore the role of decoherence in macroscopic matter-wave interference experiments and discuss the influence of the envi ronment in quantum optomechanics.\n\nA recorded version of the lecture ser ies is available upon email req uest.\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/21/ END:VEVENT BEGIN:VEVENT SUMMARY:Benjamin A. Stickler (University of Duisburg-Essen) DTSTART:20210114T100000Z DTEND:20210114T113000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/22 DESCRIPTION:Title: Lecture series: Decoherence in Macroscopic Quantum Systems\nb y Benjamin A. Stickler (University of Duisburg-Essen) as part of UniKORN s eminars\n\n\nAbstract\nSession 4: Macroscopic tests of quantum physics\n\n Session topics:\n\n\nLecture series abstract:\n\nWhile the Schrödinger equation de scribes the dynamics of isolated quantum systems\, real-world systems are always in contact with ambient environments. This leads to thermalisation as well as to decoherence\, which can explain the emergence of classical b ehaviour for objects of increasing size and complexity. This short lecture series will provide the general framework to quantitatively describe the dynamics of open quantum systems and apply it to several practically relev ant situations. Amongst others\, we will explore the role of decoherence i n macroscopic matter-wave interference experiments and discuss the influen ce of the environment in quantum optomechanics.\n\nA recorded version of t he lecture series is available upon email request.\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/22/ END:VEVENT BEGIN:VEVENT SUMMARY:Benjamin A. Stickler (University of Duisburg-Essen) DTSTART:20210113T100000Z DTEND:20210113T113000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/23 DESCRIPTION:Title: Lecture series: Decoherence in Macroscopic Quantum Systems\nb y Benjamin A. Stickler (University of Duisburg-Essen) as part of UniKORN s eminars\n\n\nAbstract\nSession 3: Decoherence and thermalisation\n\nSessio n topics:\n\n\n\nLecture se ries abstract:\n\nWhile the Schrödinger equation describes the dynamics o f isolated quantum systems\, real-world systems are always in contact with ambient environments. This leads to thermalisation as well as to decohere nce\, which can explain the emergence of classical behaviour for objects o f increasing size and complexity. This short lecture series will provide t he general framework to quantitatively describe the dynamics of open quant um systems and apply it to several practically relevant situations. Amongs t others\, we will explore the role of decoherence in macroscopic matter-w ave interference experiments and discuss the influence of the environment in quantum optomechanics.\n\nA recorded version of the lecture series is a vailable upon email request.\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/23/ END:VEVENT BEGIN:VEVENT SUMMARY:Benjamin A. Stickler (University of Duisburg-Essen) DTSTART:20210115T100000Z DTEND:20210115T113000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/24 DESCRIPTION:Title: Lecture series: Decoherence in Macroscopic Quantum Systems\nb y Benjamin A. Stickler (University of Duisburg-Essen) as part of UniKORN s eminars\n\n\nAbstract\nSession 5: Advanced topics\n\nSession topics:\n\n\n
  • Optomechanical sensing
    • \n
  • Quantum trajectories
    • \n
  • Collapse models
    • \n\n\nLecture series abstract:\n\nWhile the Sc hrödinger equation describes the dynamics of isolated quantum systems\, r eal-world systems are always in contact with ambient environments. This le ads to thermalisation as well as to decoherence\, which can explain the em ergence of classical behaviour for objects of increasing size and complexi ty. This short lecture series will provide the general framework to quanti tatively describe the dynamics of open quantum systems and apply it to sev eral practically relevant situations. Amongst others\, we will explore the role of decoherence in macroscopic matter-wave interference experiments a nd discuss the influence of the environment in quantum optomechanics.\n\nA recorded version of the lecture series is available upon email request.\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/24/ END:VEVENT BEGIN:VEVENT SUMMARY:Mauro Paternostro (Queen's University Belfast) DTSTART:20210127T140000Z DTEND:20210127T150000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/25 DESCRIPTION:Title: Seeing without looking: an optomechanical quest for quantum gravi ty\nby Mauro Paternostro (Queen's University Belfast) as part of UniKO RN seminars\n\n\nAbstract\nI will provide a general overview of the underl ying principles behind recent proposals for the exploration of the potenti al quantum nature of gravity through optomechanical settings. I will find illustrate a simple information-theoretic argument behind recent entanglem ent gain-based proposals and then discuss the implications for experimenta l endeavours based on (hybrid) optomechanics\n\nChaired by Prof Sougato Bo se\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/25/ END:VEVENT BEGIN:VEVENT SUMMARY:Igor Pikovski (University of Stockholm) DTSTART:20210203T140000Z DTEND:20210203T150000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/26 DESCRIPTION:Title: Optomechanics as a versatile tool to probe classical and quantum gravity.\nby Igor Pikovski (University of Stockholm) as part of UniKOR N seminars\n\n\nAbstract\nThe advance of optomechanical systems has helped establish a new line of research on the interface between quantum physics and gravity at low energies. In this talk\, I will discuss some of the pr oposed experiments in this field\, ranging from tests of quantum gravity m odels to gravitational wave detection with novel opto-mechanical setups. A fter giving a brief overview\, I will focus on proposals to probe quantum gravity models with a modified commutation relation that are within reach of optomechanical experiments.\n\nChaired by Prof Myungshik Kim\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/26/ END:VEVENT BEGIN:VEVENT SUMMARY:Ryan Marshman\, Sandro Donadi\, Matteo Carlesso DTSTART:20210210T140000Z DTEND:20210210T150000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/27 DESCRIPTION:Title: Quantum Nature of Linearised Gravity\, the Diósi-Penrose model & Challenges in table-top experiments\nby Ryan Marshman\, Sandro Donadi \, Matteo Carlesso as part of UniKORN seminars\n\n\nAbstract\n1st talk: "L arge Mass Interferometry for Witnessing the Quantum Nature of Linearised G ravity"\nSpeaker: Ryan Marshman\n\nAbstract: Recent work has opened up the prospect that conclusive evidence could be obtained for the quantum natur e of gravity. Specifically\, by witnessing the gravitationally generated e ntanglement which may form between two large mass interferometers. In this seminar I will discuss importance of the assumption of locality of physic al interactions\, and the concomitant necessity of propagation of an entit y (in this case\, off-shell quanta - virtual gravitons) between two non-re lativistic test masses in unveiling the quantum nature of linearised gravi ty through a laboratory experiment. In doing so I seek to provide an intui tive understanding behind the underlying physics and implications of a suc cessful experiment evidencing gravitationally mediated entanglement. \n\n- -------------------------------------------------------------------------- ---------------------\n\n2nd talk: "The Diósi-Penrose model under X-rays" \nSpeaker: Sandro Donadi\n\nAbstract: According to the Diósi-Penrose (DP) model\, quantum superpositions in space are not stable and gravity plays a role in the spontaneous decay of these superpositions in localized state s. The larger is the mass of the system\, the shorter is the time taken by the superposition to collapse. \nA direct test of this idea requires the creation of a spatial superposition which is kept stable for times longer than the one required to the gravity-related collapse to become effective. Interesting proposals have been put forward in this direction\, but they are still hard to be achieved. \n\nIn this seminar\, I will discuss a diff erent way to test the DP model. This test is based on the fact that the gr avity-related collapse predicted by the DP model also induces a Brownian-l ike motion in space of the system. For charged particles\, this Brownian-l ike motion leads to an emission of photons\, which is faint but detectable . \nWe computed the photon emission rate predicted by the DP model and com pared it with the data from a dedicated experiment performed in the ultra- low background radioactivity environment at the Gran Sasso Laboratories. O ur results rule out the parameter-free version of the model and set a stro ng bound on its parameter-dependent version.\n\n-------------------------- ----------------------------------------------------------------------\n\n 3rd talk: "Witnessing the Quantum Nature of Linearised Gravity: Challenges in table-top experiments"\nSpeaker: Matteo Carlesso\n\nAbstract: The poss ible observation of a clear quantum signature of gravity is a challenging problem. In this talk\, I will give an overview of the challenges recent t able-top experimental proposals must face. I will then compare their statu s to the required working conditions to witness possible quantum features of gravity. I will conclude briefly presenting a different scheme which ta ckles the problem from another and\, hopefully\, more feasible\, perspecti ve.\n\nChaired by Marko Toros\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/27/ END:VEVENT BEGIN:VEVENT SUMMARY:Angelo Bassi\, Miles Blencowe\, Caslav Brukner\, Ivette Fuentes\, Andrew Geraci and Gary Steele DTSTART:20210217T140000Z DTEND:20210217T153000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/28 DESCRIPTION:Title: Panel discussion "Optomechanical interfaces of quantum mechanics and gravity"\nby Angelo Bassi\, Miles Blencowe\, Caslav Brukner\, Ivet te Fuentes\, Andrew Geraci and Gary Steele as part of UniKORN seminars\n\n \nAbstract\nWe are delighted to present our panel members Angelo Bassi\, M iles Blencowe\, Caslav Brukner\, Ivette Fuentes\, Andrew Geraci and Gary S teele. The panel discussion will focus on the following three questions:\n \n1. In what experiments might we observe an interplay between quantum mec hanical and gravitational effects?\n\n2. What theoretical advances are nee ded to describe this interplay?\n\n3. What parameter regimes are the most interesting for these experiments? \n\nThe discussion will begin with shor t a introductions by each of the panel members on their views regarding th e interplay between quantum mechanics and gravity\, followed by a discussi on of the three questions listed above. After that\, the floor will be ope n to questions from the audience.\n\nChaired by Sofia Qvarfort and Hendrii k Ulbricht.\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/28/ END:VEVENT BEGIN:VEVENT SUMMARY:Warwick Bowen (School of Maths and Physics\, University of Queensl and) DTSTART:20210303T100000Z DTEND:20210303T110000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/29 DESCRIPTION:Title: Sensing beyond the conventional limits\nby Warwick Bowen (Sch ool of Maths and Physics\, University of Queensland) as part of UniKORN se minars\n\n\nAbstract\nIt has been known for over a century that\, in quant um physics\, even the act of looking can have dramatic consequences. For i nstance\, it kills the cat in Schrödinger’s famous thought experiment. However\, it has proved extremely difficult to observe such effects in pra ctice\, except for the smallest atom-scale objects\, let alone to use them as a tool to enhance technologies. \n \nOver the past decade\, however\, advances in nanotechnology have allowed us to engineer devices which exhib it this distinctive quantum behavior [1]. These “quantum optomechanical devices” consist of a nanoscale mechanical object – for example\, a na noparticle\, molecule or cantilever – coupled to light via radiation pre ssure\, often concentrated in a tiny optical cavity. In essence\, they are miniature versions of the kilometer-scale interferometers that have enabl ed the extraordinary detection of gravitational waves from distant black h ole collisions (see Figure). Quite remarkably\, they can allow measurement s of motion at the sub-attometre level – more than a thousand times belo w the width of an atomic nucleus. At a fundamental level\, this allows us to ask new questions of quantum physics for macroscopic systems consisting of trillions of atoms. It also provides a way to build precision optical sensors that far outperform the current state-of-the-art. \n \nIn this tal k\, I will provide an overview of optomechanical sensors developed in my l aboratory\, with a particular focus on applications in the biosciences. Th is includes quantum-enhanced probing of molecular vibrations that allows a bsolute quantum advantage in microscopy [2]\; optical trapping and trackin g techniques that allow speedy viscosity measurements and non-invasive sin gle molecule detection [3]\; and air-coupled optomechanical ultrasound tra nsducers with sensitivity orders-of-magnitude better than the current stat e-of-the-art [4] that could be used to listen to the sounds made by the mo tor molecules in single living cells or bacteria.\n \n\n1. Bowen and Milbu rn\, Quantum Optomechanics\, CRC Press (2016).\n\n2. arXiv:2004.00178 (20 20).\n\n3. In print\, Nature Photonics (2021)\, arXiv:2007.03066\; also Na ture Photonics 11\, 477-481 (2017)\; Nature Photonics 9\, 669-673 (2015)\; Nature Photonics 7\, 229-233 (2013).\n\n4. See e.g. Nature Communications 10\, 132 (2019).\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/29/ END:VEVENT BEGIN:VEVENT SUMMARY:Dave Moore (Yale University) DTSTART:20210310T140000Z DTEND:20210310T150000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/30 DESCRIPTION:Title: Searching for new physics with levitated optomechanics\nby Da ve Moore (Yale University) as part of UniKORN seminars\n\n\nAbstract\nThe development of precise force sensors and accelerometers based on levitated optomechanical systems is enabling searches for new fundamental interacti ons in precision experiments. I will describe the optical trapping\, contr ol\, and readout of nanogram-scale masses in vacuum optical tweezers\, and their applications to searches for new weakly coupled particles or forces . Recent searches for dark matter using these systems will be described\, as well as ongoing work to search for new forces that could appear at micr on distances.\n\nChaired by Dr. Michael Vanner\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/30/ END:VEVENT BEGIN:VEVENT SUMMARY:Nancy Aggarwal\, Ben Wood and Peng Ju DTSTART:20210317T140000Z DTEND:20210317T150000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/31 DESCRIPTION:Title: Sensing: Optomechanical Squeezing\, Superposition of Nanodiamonds & An Optically Levitated Nanorotor\nby Nancy Aggarwal\, Ben Wood and Peng Ju as part of UniKORN seminars\n\n\nAbstract\nTalk 1: Room-temperatur e optomechanical squeezing by Nancy Aggarwal\n\nAbstract: Current ground-b ased gravitational-wave (GW) detectors are large-scale optomechanical syst ems measuring displacements at the quantum limit. I will summarize the cur rent work on the quantum measurements frontier in the LIGO collaboration. I will also try to convince you that it is indeed possible for a macroscop ic\, room-temperature system to have low enough Brownian motion so as to e xhibit measureable quantum effects like squeezing [1]. \n\n[1] $\\url{http s://www.nature.com/articles/s41567-020-0877-x}$ and $\\url{https://www.nat ure.com/articles/s41586-019-1051-4}$\n\n---------------------------------- ---------------------------------------------------------\n\nTalk 2: Towar ds Macroscopic Spatial Superposition of Nanodiamonds by Ben Wood\n\n\nAbst ract: Nanodiamonds containing negatively charged nitrogen vacancy centres (NV) have been proposed as a platform to generate macroscopic spatial quan tum superpositions. These superpositions could be used as highly sensitive gravity sensors or even to probe the quantum nature of gravity\, however\ , experimental challenges need to be overcome to realise these proposals. In this talk I will discuss current work on three of these challenges. Fir stly\, we have measured long\, room temperature\, spin coherence times of NV in nanodiamonds produced by silicon nitride ball milling. Secondly\, we are developing a diamagnetic trap for passive neutral-nanodiamond levitat ion. Finally\, we propose a magnetic field structure to generate a spatial superposition in a free-fall experiment\, allowing for dynamical decoupli ng spin flips.\n\n-------------------------------------------------------- -----------------------------------\n\nTalk 3: Ultrasensitive torque detec tion with an optically levitated nanorotor by Peng Ju\n\nAbstract: Torque sensors such as the torsion balance enabled the first determination of the gravitational constant by Henri Cavendish and the discovery of Coulomb’ s law. Great effort has been made to get more sensitive torque sensors\, w hich are widely used in studying small-scale magnetism\, the Casimir effec t and other applications. With an optically levitated silica nanoparticle in vacuum\, we are able to reach a record torque sensitivity of $(4.2 \\pm 1.2) \\times 10^{-27}$ Nm Hz$^{-1/2}$ at room temperature. Moreover\, we drive a nanoparticle to rotate at a high speed beyond 5 GHz(300 billion r. p.m.). Our calculations show that this system will be able to detect the l ong-sought-after vacuum friction near a surface under realistic conditions .\n\n[1] $\\url{https://www.nature.com/articles/s41565-019-0605-9}$\n\nCha ired by Maryam Nikkhou.\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/31/ END:VEVENT BEGIN:VEVENT SUMMARY:Kai Bongs\, John Davis\, Gabriella Mifsud\, Clemens Schäfermeier and Douglas Paul (University of Birmingham\, University of Alberta\, Accel er8\, AttoCube and University of Glasgow) DTSTART:20210324T150000Z DTEND:20210324T163000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/32 DESCRIPTION:Title: Panel discussion: How do you build and sell an optomechanical sen sor?\nby Kai Bongs\, John Davis\, Gabriella Mifsud\, Clemens Schäferm eier and Douglas Paul (University of Birmingham\, University of Alberta\, Acceler8\, AttoCube and University of Glasgow) as part of UniKORN seminars \n\n\nAbstract\nWe live in an exciting era where the commercialisation of various quantum technologies is quickly becoming reality. However\, there are a number of challenges beyond fundamental research that accompany the development and commercialisation of a product. In this panel discussion\, which brings together experts from industry and academia\, we ask the que stion: “How do you build and sell an optomechanical sensor?”. The disc ussion will focus on how to identify research as suitable for commercialis ation and building a creative and productive environment for these researc h outputs. We will also discuss the question of marketing and selling the technology.\n\nChaired by James Millen.\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/32/ END:VEVENT BEGIN:VEVENT SUMMARY:Stefano Vitale (University of Trento/IstitutoNazionale di Fisica N ucleare/Agenzia Spaziale Italiana) DTSTART:20210407T130000Z DTEND:20210407T140000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/33 DESCRIPTION:Title: LISA Pathfinder and LISA\nby Stefano Vitale (University of Tr ento/IstitutoNazionale di Fisica Nucleare/Agenzia Spaziale Italiana) as pa rt of UniKORN seminars\n\n\nAbstract\nLISA is a space-borne gravitational wave (GW) observatory under development by the European Space Agency (ESA) . It aims at the GW spectrum between a few tens of micro-Hz and a fraction of a Hz\, which cannot be accessed by ground-based detectors. LISA has b een preceded by a precursor mission\, LISA Pathfinder\, that has successfu lly demonstrated the necessary space-time metrology. \nThe talk will revie w both the basic principles of LISA and the status of its development\, and the objectives\, design\, operations and achievements of LISA Pathfin der.\n\nChaired by Giles Hammond.\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/33/ END:VEVENT BEGIN:VEVENT SUMMARY:Rainer Kaltenbaek (Faculty of Mathematics and Physics\, University of Ljubljana) DTSTART:20210414T130000Z DTEND:20210414T140000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/34 DESCRIPTION:Title: Testing quantum physics in space: challenges and progress\nby Rainer Kaltenbaek (Faculty of Mathematics and Physics\, University of Lju bljana) as part of UniKORN seminars\n\n\nAbstract\nSince its inception in 2010\, significant progress has been made in the development of the MAQRO mission proposal to build a dedicated satellite for testing the foundation s of quantum physics. In 2017\, the European Space Agency (ESA) chose this as one of its New Science Ideas for future missions\, and it conducted a detailed study at their Concurrent Design Facility (CDF) on the technical feasibility of a future quantum physics platform (QPPF) based on the MAQRO mission concept. The conclusion of the study was that such a mission is f easible\, in principle\, but that three critical\, technical challenges ha ve to be met before a potential future implementation. Here\, we will disc uss these challenges\, recent progress\, as well as planned and on-going r esearch activities to meet these challenges.\n\nChaired by Gavin Morley.\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/34/ END:VEVENT BEGIN:VEVENT SUMMARY:Jasminder Sidhu\, Christian Vogt\, Stephan Tobias Seidel (Universi ty of Strathclyde\, Universität Bremen\, Airbus) DTSTART:20210421T130000Z DTEND:20210421T140000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/35 DESCRIPTION:Title: Photonics\, nanoparticles and cold-atoms as role models for space -based test with optomechanics\nby Jasminder Sidhu\, Christian Vogt\, Stephan Tobias Seidel (University of Strathclyde\, Universität Bremen\, A irbus) as part of UniKORN seminars\n\n\nAbstract\n1st talk: Satellite-base d Quantum Communications\;\nSpeaker: Jasminder Sidhu\n\nAbstract: Global q uantum communications is important for distributed quantum information pro cessing over long-distances\, and entanglement-enabled technologies. Howev er\, range limitations of fibre optical transmission restricts the reach o f networked quantum technologies. Satellite-based quantum communication pr ovides a practical and realisable route to intercontinental quantum networ king\, and is rapidly being developed. In this talk\, we briefly review th ese developments and highlight some of the unique challenges in space-base d quantum communications.\n\n--------------------------------------------- ---------------------------------------------------\n\n2nd talk: Cooled na noparticles in a drop tower\;\nSpeaker: Christian Vogt\n\nAbstract:\nLevit ated optomechanics based on levitated silica nanospheres is a promising to ol for force measurements and observation of the quantum mechanical behavi or of "large" masses. Especially the latter benefits strongly from a space environment\, as proposed in MAQRO mission.\nNevertheless\, space-based e xperiments rely on rigorous preparation and need as much validation of the proposed techniques as possible\, including under weightlessness conditio ns. Our approach is to operate a system with parametrically cooled nanopar ticles in the drop tower in Bremen\, providing 4.7 s of weightlessness tim e\, 9.3 s in catapult mode. \nBeyond demonstrating feasibility\, such an e xperiment allows for the realization of even slower nanoparticles\, increa sed force sensitivity\, or even "macroscopic" interference. This talk will discuss the various ideas for drop tower applications\, its benefits for ground-based experiments\, and how we can support these with our findings on optically trapped neutral atoms in the drop tower.\n\n\n--------------- -------------------------------------------------------------------------- -------\n\n3rd talk: Cold Atom Interferometry in Space\;\nSpeaker: Stephan Tobias Seidel\n\nAbstract:\nCold Atom Interferometers (CAI) are quantum s ensors based on the interference of matterwaves that allow for measurement s of accelerations and rotations with a high accuracy. The realisation of CAIs in microgravity allows to drastically increase the free interrogation time of the atoms in the CAI compared to measurements in gravity. This in turn\, increases the sensitivity of the measurement as it scales quadrati cally with the free interrogation time.\nThis talk will briefly discuss th e principles of CAIs\, their applications in space and the current state o f microgravity demonstrations.\n\nChaired by Lisa Wörner.\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/35/ END:VEVENT BEGIN:VEVENT SUMMARY:Mike Cruise\, Chris Lee\, James Endicott\, Daniel Oi (University o f Birmingham\, Space Academic Network\, Open University\, University of St rathclyde) DTSTART:20210428T130000Z DTEND:20210428T143000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/36 DESCRIPTION:Title: Panel discussion: Space-based tests with optomechanics\nby Mi ke Cruise\, Chris Lee\, James Endicott\, Daniel Oi (University of Birmingh am\, Space Academic Network\, Open University\, University of Strathclyde) as part of UniKORN seminars\n\n\nAbstract\nPanel discussion with the diff erent academic and industrial stakeholders involved in the UK’s roadmap of space exploration and how in particular space-based tests with optomech anics fit into this broader context. A few of the questions we will try to answer will include: \n\n- Why should we try to do physics in space?\n\n- What are the advantages provided\, in the context of quantum tests in spa ce\, by the use of small satellites? How can we exploit them as kick-start ers to advance technology?\n\n- What is the added value that would be prov ided by optomechanical platforms?\n\n- How can we connect optomechanical s ystems in space networks?\n\nChaired by Mauro Paternostro.\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/36/ END:VEVENT BEGIN:VEVENT SUMMARY:Albert Schliesser (Neils Bohr Institute) DTSTART:20210512T130000Z DTEND:20210512T140000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/37 DESCRIPTION:Title: Measurement-based quantum control of macroscopic motion\nby A lbert Schliesser (Neils Bohr Institute) as part of UniKORN seminars\n\n\nA bstract\nOver the last 15 years\, we have seen dramatic advances in the ab ility to control the quantum state of nano- and micro-mechanical systems\, by coupling them to light or microwaves. Coherent control\, such as laser sideband cooling\, has been used successfully to prepare low-entropy quan tum states of mechanical systems. In this talk\, I will focus on a differe nt paradigm\, namely measurement-based quantum control. \nUsing optical in terferometry\, we monitor the motion of the membrane with attometer sensit ivity. The membranes host extremely coherent mechanical resonance modes\, shielded from the environment by a phononic crystal pattern. In this setti ng\, we directly observe the quantum back-action of the measurement proces s on the measured object in the form of quantum fluctuations of radiation pressure. By trading off imprecision and back-action\, we closely approach the standard quantum limit (SQL) in the sensitivity to mechanical displac ement. We then use the information gained through the measurement to obtai n pure mechanical quantum trajectories (conditioned the measurement record ). By applying real-time feedback\, we can also prepare an unconditional l ow-entropy quantum state. Interestingly\, exploiting quantum correlations born in the measurement process\, we can even overcome the SQL in displace ment and force measurements. Based on the same underlying correlations\, w e evidence entanglement in the optical output modes of the system.\nI will conclude with a short outlook on potential applications in future quantum technologies.\n\nChaired by Peter Barker.\nRecorded talk available upon < a href="mailto:unikorn.seminars@gmail.com?subject=Link%20request%20for%20r ecorded%20talk%20by%20Albert%20Schliesser&body=Dear%20UniKORN%20organiser% 20team%2C%0A%0ACould%20you%20please%20share%20the%20link%20to%20the%20reco rded%20talk%20by%20Albert%20Schliesser%20with%20the%20title%3A%20Measureme nt-based%20quantum%20control%20of%20macroscopic%20motion%3F%0A%0AI%20will% 20not%20redistribute%20this%20link%20publicly%20and%20intend%20to%20use%20 it%20only%20for%20my%20own%20educational%20purposes.%20%0A%0ABest%20wishes %2C%0A">email request.\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/37/ END:VEVENT BEGIN:VEVENT SUMMARY:John Teufel (NIST/Boulder) DTSTART:20210519T130000Z DTEND:20210519T140000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/38 DESCRIPTION:Title: Listening to the Sound of Entanglement\nby John Teufel (NIST/ Boulder) as part of UniKORN seminars\n\n\nAbstract\nQuantum mechanics is t raditionally considered when measuring at the extreme microscopic scale\, i.e. single photons\, electrons or atoms. However\, even the early pionee rs of the quantum theory postulated gedanken experiments in which quantum effects would manifest on an everyday scale. I will present recent experim ents in which we engineer and measure microelectromechanical (MEMs) circui ts to observe and to exploit quantum behavior at an increasingly macroscop ic scale. By embedding mechanical resonators in superconducting microwave circuits\, we achieve strong radiation-pressure coupling between fields a nd motion that allows us to perform quantum experiments of massive objects . I will present our recent experimental demonstration of deterministic m acroscopic entanglement\, as well as ongoing efforts toward arbitrary quan tum control of mechanical systems. The ability to prepare and to “liste n” to quantum sound has implications for fundamental science as well as many powerful applications including the processing\, storage and networki ng of quantum information.\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/38/ END:VEVENT BEGIN:VEVENT SUMMARY:Ricardo Puebla Antunes\, Clara Wanjura & John Price (IFF-CSIC\, U niversity of Cambridge\, Imperial College London) DTSTART:20210526T130000Z DTEND:20210526T140000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/39 DESCRIPTION:Title: Frontiers talks on State Preperation & Control\nby Ricardo Pu ebla Antunes\, Clara Wanjura & John Price (IFF-CSIC\, University of Cambr idge\, Imperial College London) as part of UniKORN seminars\n\n\nAbstract\ nTalk 1: Quantum control in spin-boson systems via shortcuts to adiabatici ty by Ricardo Puebla Antunes\n\n \nAbstract: The design of fast and robust time-dependent protocols to control quantum systems is one of the main ch allenges in quantum state preparation\, and thus essential for the develop ment of technologies aiming at harnessing quantum effects. Among the diffe rent strategies that have been put forward in this context\, an adiabatic control of the system's parameters merits special attention thanks to its simplicity and its ability to typically provide useful and interesting qua ntum states. However\, such adiabatic control is prone to decoherence effe cts as it can only be achieved by slowly varying the system's parameters\, that is\, in a time scale generally larger than the decoherence time. Yet \, it has been recently shown that the result of an adiabatic control can be exactly obtained in an arbitrary time by employing a suitable protocol\ , i.e. by taking a shortcut [1]. This sped-up adiabatic control\, or as c ommonly known\, the shortcut to adiabaticity allows therefore to realize t he desired protocol before decoherence effects become significant\, but it comes at the price of demanding both more tunability and control on the s ystem of interest. In this talk I will focus on the application of protoco ls built on shortcuts to adiabaticity to generate non-classical states of a bosonic mode exploiting a coherent exchange of excitations with a two-le vel system ruled by a Jaynes-Cummings interaction mechanism [2]. These pro tocols allow for the generation of arbitrary Fock states of the bosonic mo de\, as well as coherent quantum superpositions of a Schrödinger cat-like form. In addition\, I will illustrate how to obtain a class of photon-shi fted states where the vacuum population is removed\, a result akin to phot on addition\, but displaying more non-classicality than standard photon-ad ded states. \n\n[1] D. Guéry-Odelin\, et al.\, Rev. Mod. Phys. 91\, 0450 01 (2019)\n\n[2] O. Abah\, R. Puebla\, and M. Paternostro\, Phys. Rev. Let t. 124\, 180401 (2020)\n\n\n---------------------------------------------- ---------------------------------------------\n\n\nSpeaker 2: Title: Topol ogical framework for directional amplification in driven-dissipative cavit y arrays by Clara Wanjura\n\n\nAbstract: Directional amplification\, in wh ich signals are selectively amplified depending on their propagation direc tion\, has attracted much attention as key resource for applications\, inc luding quantum information processing. Recently\, several\, physically ver y different\, directional amplifiers have been proposed and realized in th e lab.\n\nIn this talk\, I will present a unifying framework based on topo logy to understand non-reciprocity and directional amplification in driven -dissipative cavity arrays [1]. Specifically\, we have shown that there is a one-to-one correspondence between a non-zero invariant of non-Hermitian topology defined on the spectrum of the dynamic matrix and regimes of dir ectional amplification\, in which the end-to-end gain grows exponentially with the number of cavities. Our framework allows us to analytically compu te the scattering matrix\, the gain and reverse gain which explicitly depe nd on the value of the topological invariant. Parameter regimes achieving directional amplification can be elegantly obtained from a topological ‘ phase diagram’\, which provides a guiding principle for the design of bo th phase-preserving and phase-sensitive multimode directional amplifiers.\ n\nRealistic systems are always subject to disorder. I will show\, however \, that topological\, directional amplification is extremely robust agains t disorder [2]. Indeed\, the separation between the complex spectrum and t he origin (the size of the point gap) determines the amount of tolerated d isorder. Furthermore\, we have shown that the zero reverse gain associated with exceptional points remains exactly zero in the presence of arbitrary on-site disorder.\n\n\n[1] C. C. Wanjura\, M. Brunelli\, A. Nunnenkamp. T opological framework for directional amplification in driven-dissipative c avity arrays. Nat Commun 11\, 3149 (2020).\n\n[2] C. C. Wanjura\, M. Brune lli\, A. Nunnenkamp. Correspondence between non-Hermitian topology and dir ectional amplification in the presence of disorder (2020). Preprint at htt ps://arxiv.org/abs/2010.14513\n\n\n--------------------------------------- ----------------------------------------------------\n\nTalk 3: Single- an d multi-phonon subtraction in whispering-gallery-mode\nmicroresonators by John Price\n\n\nAbstract: Brillouin scattering in optical microresonators offers a promising avenue for quantum optomechanics applications owing to several favourable properties including: high mechanical frequencies\, str ong optomechanical coupling\, and low optical absorption and heating. Our lab is utilising these properties to perform measurement-based state prepa ration and readout of mechanical motional states. In this talk I will disc uss recent experiments combining photon counting and optical heterodyne de tection\, where we perform single- and multiphonon subtraction to a whispe ring-gallery-mode Brillouin\noptomechanical system. We observe that these operations counterintuitively approximately double and triple the mean occ upation of the state\, respectively [1]. Furthermore\, we reconstruct the sparameterised Wigner phase-space distribution\, and the observe the resul ting non-Gaussianity in the prepared states [2].\n\n[1] G. Enzian\, L. Fre isem\, J. J. Price\, J. Nunn\, J. Janousek\, B. C. Buchler\, P. K. Lam\, a nd M. R. Vanner “Single-Phonon Addition and Subtraction to a Mechanical Thermal State\,” Physical Review Letters 126\, 033601 (2021).\n\n[2] G. Enzian\, L. Freisem\, J. J. Price\, A. Ø. Svela\, J. Clarke\, B. Shajilal \, J. Janousek\, B. C. Buchler\, P. K. Lam\, and M. R. Vanner\, “Non-Gau ssian mechanical motion via single and multi-phonon subtraction from a the rmal state\,” arxiv:2103.05175\, (2021).\n\nChaired by Saba Khan.\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/39/ END:VEVENT BEGIN:VEVENT SUMMARY:Tracy Northup\, Yuwen Chu\, Ewold Verhagen\, Andre Xuereb DTSTART:20210609T130000Z DTEND:20210609T143000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/40 DESCRIPTION:Title: Panel discussion on "Beyond the Quantum Ground State"\nby Tra cy Northup\, Yuwen Chu\, Ewold Verhagen\, Andre Xuereb as part of UniKORN seminars\n\n\nAbstract\nThis panel discussion will explore mechanical syst ems “beyond the ground state” drawing on expertise and knowledge from neighbouring fields. We will be specifically interested in understanding h ow to create non-classical states of macroscopic mechanical oscillators. H ow to characterize quantum states and identify nonclassicality? What are t he roles of open-system dynamics? What are the spectrum of experimental an d theoretical tools currently at our disposal? The panellists will draw on state-of-the-art results\, as well as their expertise of neighbouring fie lds such as atomic ions\, superconducting qubits\, and quantum optics.\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/40/ END:VEVENT BEGIN:VEVENT SUMMARY:Poster session I DTSTART:20210616T130000Z DTEND:20210616T143000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/41 DESCRIPTION:Title: UniKORN Virtual Poster Session\nby Poster session I as part o f UniKORN seminars\n\n\nAbstract\nTo round off a year of virtual seminars\ , UniKORN is organising the two virtual poster sessions. They will be held on the 16th and 23rd of June at 14:00-15:30 BST online on the Gather Town platform\, where you can network and socialise with other optomechanics r esearchers. We encourage everyone to join in and submit a poster\, but we particularly encourage PhD students and postdocs to join.\n\n \nIn each se ssion\, we will select a poster for a £100 book voucher poster prize. The judges include representatives from the British Optomechanics Research Ne twork\, Nature and EPSRC.\n\n \nTo register for the poster sessions\, plea se fill out the above form. Note that you will not be able to join the ses sion unless you have registered using the form. The Registration deadline for poster submissions is the 2nd of June 2021.\n \nWe aim for both sessio ns to have an equal number of people and will try our best to allocate the posters accordingly. More information\, including specifications and inst ructions on how to upload your poster will be sent out in the two weeks pr ior to the event.\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/41/ END:VEVENT BEGIN:VEVENT SUMMARY:Poster session II DTSTART:20210623T130000Z DTEND:20210623T143000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/42 DESCRIPTION:Title: UniKORN Virtual Poster Session\nby Poster session II as part of UniKORN seminars\n\n\nAbstract\nTo round off a year of virtual seminars \, UniKORN is organising the two virtual poster sessions. They will be hel d on the 16th and 23rd of June at 14:00-15:30 BST online on the Gather Tow n platform\, where you can network and socialise with other optomechanics researchers. We encourage everyone to join in and submit a poster\, but we particularly encourage PhD students and postdocs to join.\n\n \nIn each s ession\, we will select a poster for a £100 book voucher poster prize. Th e judges include representatives from the British Optomechanics Research N etwork\, Nature and EPSRC.\n\n \nTo register for the poster sessions\, ple ase fill out the above form. Note that you will not be able to join the se ssion unless you have registered using the form. The Registration deadline for poster submissions is the 2nd of June 2021.\n \nWe aim for both sessi ons to have an equal number of people and will try our best to allocate th e posters accordingly. More information\, including specifications and ins tructions on how to upload your poster will be sent out in the two weeks p rior to the event.\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/42/ END:VEVENT BEGIN:VEVENT SUMMARY:Carla Faria and Charles Adams DTSTART:20210630T130000Z DTEND:20210630T140000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/43 DESCRIPTION:Title: A conversation on: How do you run a research group?\nby Carla Faria and Charles Adams as part of UniKORN seminars\n\n\nAbstract\nJoin u s for this conversation on how you build and manage a research group toget her with Prof Carla Faria and Prof Charles Adams. The session will be chai red by Dr Xavier Rojas.\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/43/ END:VEVENT BEGIN:VEVENT SUMMARY:Panel discussion DTSTART:20210707T130000Z DTEND:20210707T143000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/44 DESCRIPTION:Title: Panel discussion: How do you build a research network?\nby Pa nel discussion as part of UniKORN seminars\n\n\nAbstract\nPlease join us f or this discussion on "How do you build a research network?". We are pleas ed to welcome participants from the Knowledge Transfer Network\, The Black ett Lab Family\, the Marie Sklodowska-Curie Action Alumni network\, and EP SRC.\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/44/ END:VEVENT BEGIN:VEVENT SUMMARY:Marko Toroš\, Philipp Treutlein (University of Glasgow\, Universi ty of Basel) DTSTART:20211006T130000Z DTEND:20211006T140000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/47 DESCRIPTION:Title: Creating atom-nanoparticle quantum superposition & Coupling quant um systems with a laser loop\nby Marko Toroš\, Philipp Treutlein (Uni versity of Glasgow\, University of Basel) as part of UniKORN seminars\n\n\ nAbstract\nMarko Toroš: Creating atom-nanoparticle quantum superposition\ n\nHybrid optomechanical systems offer a unique potential for quantum tech nologies as well as for exploring the boundaries of quantum mechanics. In this talk I will present an atom-nanoparticle hybrid system that can be us ed as a matter-wave probe of external fields [1]. I will show how to contr ol a large ∼500-nm nanoparticle using the internal state of the atom so as to create\, as well as detect\, non-classical motional states of the na noparticle. Specifically\, I will consider a setup based on a silica nanop article coupled to a Cesium atom and discuss a protocol for preparing and verifying a Schrödinger-cat state of the nanoparticle that does not requi re cooling to the motional ground state. I will finally show that the exis tence of the superposition can be revealed using the Earth's gravitational field using a method that is insensitive to the most common sources of de coherence and works for any initial state of the nanoparticle.\n\n[1] M. T oroš\, S. Bose\, and P. F. Barker\, Creating atom-nanoparticle quantum su perposition\, Phys. Rev. Research 3\, 033218 (2021)\n\n------------------- ------------------------------------------------------------------------\n \n\nPhilipp Treutlein: Coupling quantum systems with a laser loop\n\nMany of the breakthroughs in quantum science and technology rely on engineering strong Hamiltonian interactions between quantum systems. Typically\, stro ng coupling relies on short-range forces or on placing the systems in high -quality electromagnetic resonators\, which restricts the range of the cou pling to short distances. In this talk I will show how a loop of laser lig ht can generate Hamiltonian coupling over a distance [1] and report experi ments using this approach to strongly couple a nanomechanical membrane osc illator and an atomic spin ensemble across one meter in a room-temperature environment [2]. We observe spin-membrane normal mode splitting\, coheren t energy exchange oscillations\, two-mode thermal noise squeezing\, dissip ative coupling with exceptional points\, and sympathetic cooling of the me mbrane. Our experiments demonstrate the versatility and flexibility of lig ht-mediated interactions\, a powerful tool for quantum science that offers many further possiblities and is readily applicable to a variety of diffe rent systems.\n\n[1] T. M. Karg\, B. Gouraud\, P. Treutlein\, and K. Hamme rer\, Remote Hamiltonian interactions mediated by light\, Phys. Rev. A 99\ , 063829 (2019).\n\n[2] T. M. Karg\, B. Gouraud\, C. T. Ngai\, G.-L. Schmi d\, K. Hammerer\, and P. Treutlein\, Light-mediated strong coupling betwee n a mechanical oscillator and atomic spins one meter apart\, Science 369\, 174 (2020).\n\nChaired by Peter Barker.\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/47/ END:VEVENT BEGIN:VEVENT SUMMARY:Cindy Regal\, Yiwen Chu\, Florian Marquardt\, Peter Rabl (Universi ty of Colorado Boulder\, ETH Zurich\, MPI for Science of Light\, TU Wien) DTSTART:20211013T130000Z DTEND:20211013T143000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/48 DESCRIPTION:Title: Panel discussion on hybrid optomechanics\nby Cindy Regal\, Yi wen Chu\, Florian Marquardt\, Peter Rabl (University of Colorado Boulder\, ETH Zurich\, MPI for Science of Light\, TU Wien) as part of UniKORN semin ars\n\n\nAbstract\nThe panel discussion will make an attempt at evaluating the current state of the art of hybrid optomechanics and giving new input by tackling open questions and combining different perspectives. The virt ual floor will be opened for audience participation in the form of questio ns or discussion points after some initial moderated discussion.\n\nChaire d by Edward Laird (Lancaster University)\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/48/ END:VEVENT BEGIN:VEVENT SUMMARY:Juliette Monsel\, Mauro Paternostro DTSTART:20211103T140000Z DTEND:20211103T150000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/49 DESCRIPTION:Title: Block 7 - Nonequilibrium Physics and Nano thermodynamics: ECR + I ntroduction\nby Juliette Monsel\, Mauro Paternostro as part of UniKORN seminars\n\n\nAbstract\nFrontiers Talk - By Juliette Monsel\n\n\nAbstract :\n\nOptomechanical cooling with coherent and squeezed light: The thermody namic cost of opening the heat valve\n\nGround-state cooling of mechanical motion by coupling to a driven optical cavity has been demonstrated in va rious optomechanical systems. In our paper\, we provide a thermodynamic pe rformance analysis of optomechanical sideband cooling in terms of a heat v alve. As performance quantifiers\, we examine not only the lowest reachabl e effective temperature (phonon number) but also the evacuated-heat flow a s an equivalent to the cooling power of a standard refrigerator\, as well as appropriate thermodynamic efficiencies\, which all can be experimentall y inferred from measurements of the cavity output light field. Importantly \, in addition to the standard optomechanical setup fed by coherent light\ , we investigate two recent alternative setups for achieving ground-state cooling: replacing the coherent laser drive by squeezed light or using a c avity with a frequency-dependent (Fano) mirror. We study the dynamics of t hese setups within and beyond the weak-coupling limit and give concrete ex amples based on parameters of existing experimental systems. By applying o ur thermodynamic framework\, we gain detailed insights into these three di fferent optomechanical cooling setups\, allowing a comprehensive understan ding of the thermodynamic mechanisms at play [1].\n\n[1] J. Monsel\, N. Da shti\, S. K. Manjeshwar\, J. Eriksson\, H. Ernbrink\, E. Olsson\, E. Torne us\, W. Wieczorek\, J. Splettstoesser: Phys. Rev. A 103\, 063519 (2021)\n\ n\n----------------------- \n\nPerspectives Talk - By Mauro Paternostro\n\ nAbstract: Non-equilibrium thermodynamics of quantum processes -- an optom echanical perspective\n\nI will give a high-level introduction to non-equi librium thermodynamics of quantum systems and processes\, building the cas e for its optomechanical exploration. I will illustrate recent achievement s and possible ways forward made available by the control that is currentl y possible in such platform.\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/49/ END:VEVENT BEGIN:VEVENT SUMMARY:Janet Anders\, Raúl Rica\, Raam Uzdin\, Nikolai Kiesel (Universit y of Exeter\, University of Granada\, Hebrew University of Jerusalem\, Uni versity of Vienna) DTSTART:20211110T140000Z DTEND:20211110T153000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/52 DESCRIPTION:Title: Panel discussion on Optomechanical Machines\nby Janet Anders\ , Raúl Rica\, Raam Uzdin\, Nikolai Kiesel (University of Exeter\, Univers ity of Granada\, Hebrew University of Jerusalem\, University of Vienna) as part of UniKORN seminars\n\n\nAbstract\nPanel discussion on ‘Optomechan ical machines'. We are delighted to present Janet Anders\, Raúl Rica\, Ra am Uzdin and Nikolai Kiesel as the panellist.\n\nChaired by James Millen.\ n LOCATION:https://researchseminars.org/talk/UniKORNseminars/52/ END:VEVENT BEGIN:VEVENT SUMMARY:Otto Muskens\, Mika Sillanpää (University of Southampton\, Aalto University) DTSTART:20211201T140000Z DTEND:20211201T150000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/54 DESCRIPTION:Title: Block 8 - Nanofabricating optomechanics\nby Otto Muskens\, Mi ka Sillanpää (University of Southampton\, Aalto University) as part of U niKORN seminars\n\n\nAbstract\nFrontiers talk by Otto Muskens\n\nTitle: “What’s the meta with optomechanical metasurfaces”\n\nAbstract: Meta materials have been invented as man-made artificial materials with new pro perties often unattainable in natural materials. Metamaterials typically c onsist of optically resonant building blocks (metamolecules) stacked toget her to achieve an effective optical response. Metasurfaces represent a sub -category of devices where a single layer of metamolecules allow control o ver wavefronts with many new applications in e.g. flat optics\, holograms and frequency selective surfaces. Combining the degrees of freedom offered by metasurfaces with optomechanics is of interest for achieving extremely nonlinear devices where vibrations and light are coupled together. We hav e investigated metasurfaces where the fundamental metamolecules support bo th optical and gigahertz vibrational resonances. Devices were fabricated u sing focused ion-beam milling in a 300nm thick free-standing silicon carbi de (SiC) membrane. We use optical pump-probe spectroscopy to impulsively e xcite the vibrational modes though a metasurface optical resonance. Detect ion takes place with a second\, time-delayed pulse at a different waveleng th corresponding to another optically resonant mode\, thus benefiting from the enhanced sensitivity of the metasurface. Our results on wavelength an d polarization-dependent excitation of vibrations are interpreted using an optical force-induced excitation mechanism. We explore the local variatio ns of the vibrational modes over the metasurface\, and show that the respo nse is characterised by an inhomogeneous distribution of vibrational frequ encies related to local variations in nanofabrication and membrane charact eristics. This study reveals some of the challenges and opportunities offe red by combining optical and mechanical metasurfaces in the regime of high mechanical frequencies.\n\n\nIntroductory talk by Mika Sillanpää \n\nTi tle: (Microwave) optomechanics in the quantum regime\n\nAbstract: Mechanic al oscillators affected by radiation pressure forces allow to address fund amental questions on quantum properties of moving objects\, or\, to explor e quantum limits in measurements. Additionally\, micro- or nanomechanical devices have shown strong promise for supporting components in quantum tec hnology\, for example\, for communication and information storage. An inte resting setup for cavity optomechanics consists of superconducting on-chip microwave cavities coupled to a micromechanical vibrating membranes. Afte r an introduction to (microwave) optomechanics in the quantum regime\, I s how how it is possible to measure a mechanical oscillator without quantum back-action of the measurement by constructing one effective oscillator fr om two physical oscillators. We realize such a quantum mechanics-free subs ystem in microwave optomechanics\, and show the measurements of two collec tive quadratures while evading the quantum back-action by 8 decibels on bo th of them\, obtaining a total noise within a factor of 2 of the full quan tum limit. By perturbing the measurement slightly\, such measurements coul d be used to generate stabilized entanglement between two macroscopic mech anical oscillators. This prepares a canonical entangled state known as the two-mode squeezed state. It corresponds to the variances of collective po sition and momentum quadratures being reduced below the quantum zero-point fluctuations level. Moreover\, our approach allows for full tomographic c haracterization of the prepared entangled state. We carry out this measure ment\, and verify the existence of entanglement in the steady state by dir ect access to fluctuations in all the collective motional quadratures.\n\n Chaired by Xavier Rojas.\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/54/ END:VEVENT BEGIN:VEVENT SUMMARY:Panel discussion: Paul Seidler\, Prof Pavel Ginzburg\, John R. Law all\, Prof Shankar Kumar and Guilhem Madiot (IBM Research\,Tel Aviv Univer sity\, NIST\, IISc and ICN2) DTSTART:20211208T140000Z DTEND:20211208T153000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/55 DESCRIPTION:Title: Block 8 - Nanofabricating optomechanics\nby Panel discussion: Paul Seidler\, Prof Pavel Ginzburg\, John R. Lawall\, Prof Shankar Kumar and Guilhem Madiot (IBM Research\,Tel Aviv University\, NIST\, IISc and IC N2) as part of UniKORN seminars\n\n\nAbstract\nRecent developments in nano fabrication technology have provided a unique platform - from extremely se nsitive on-chip sensing to exploring foundational questions in quantum mec hanics. This discussion will explore the impact of modern nanotechnology o n optomechanical research.\n\nChaired by Sergey Kafanov.\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/55/ END:VEVENT BEGIN:VEVENT SUMMARY:Vittorio Peano (Max Planck Institute for the Science of Light) DTSTART:20220117T100000Z DTEND:20220117T113000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/56 DESCRIPTION:Title: Lecture Series on Cavity Optomechanics: From basics concepts to advanced applications\nby Vittorio Peano (Max Planck Institute for the Science of Light) as part of UniKORN seminars\n\n\nAbstract\nMonday: Moti vation\, radiation forces\, optomechanical Hamiltonian\, and optomechanica l platforms\n\n----------------------------------------------------\n\nLec ture Abstract: \n\nThe tail of a comet always points away from the sun. B ack in the 17th century\, Kepler explained this observation proposing that light exerts a force on matter\, the so-called radiation pressure force. Four hundred years later technological progress has allowed studying this force in a completely different playground: high-finesse cavities allow to concentrate very high radiation intensities on lightweight mechanical d evices that are exceptionally well shielded from the neighbouring environm ent. In these cavity-optomechanics platforms\, the radiation pressure for ce can have a strong impact on the mechanical component on a time scale th at can be shorter than the typical time for absorbing a single phonon from the environment. This has allowed reaching landmark achievements like coo ling a mechanical oscillator to its ground state\, squeezing the electroma gnetic vacuum and measuring gravitational waves. In this series of lecture s\, I will give a didactic overview of the field of cavity optomechanics.\ n LOCATION:https://researchseminars.org/talk/UniKORNseminars/56/ END:VEVENT BEGIN:VEVENT SUMMARY:Vittorio Peano (Max Planck Institute for the Science of Light) DTSTART:20220118T100000Z DTEND:20220118T113000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/57 DESCRIPTION:Title: Lecture Series on Cavity Optomechanics: From basics concepts to advanced applications\nby Vittorio Peano (Max Planck Institute for the Science of Light) as part of UniKORN seminars\n\n\nAbstract\nTuesday: Pre cision sensing\, gravitational interferometers and standard quantum limit\ n\n----------------------------------------------------\n\nLecture Abstrac t: \n\nThe tail of a comet always points away from the sun. Back in the 1 7th century\, Kepler explained this observation proposing that light exert s a force on matter\, the so-called radiation pressure force. Four hundre d years later technological progress has allowed studying this force in a completely different playground: high-finesse cavities allow to concentra te very high radiation intensities on lightweight mechanical devices that are exceptionally well shielded from the neighbouring environment. In the se cavity-optomechanics platforms\, the radiation pressure force can have a strong impact on the mechanical component on a time scale that can be sh orter than the typical time for absorbing a single phonon from the environ ment. This has allowed reaching landmark achievements like cooling a mecha nical oscillator to its ground state\, squeezing the electromagnetic vacuu m and measuring gravitational waves. In this series of lectures\, I will g ive a didactic overview of the field of cavity optomechanics.\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/57/ END:VEVENT BEGIN:VEVENT SUMMARY:Vittorio Peano (Max Planck Institute for the Science of Light) DTSTART:20220119T100000Z DTEND:20220119T113000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/58 DESCRIPTION:Title: Lecture Series on Cavity Optomechanics: From basics concepts to advanced applications\nby Vittorio Peano (Max Planck Institute for the Science of Light) as part of UniKORN seminars\n\n\nAbstract\nWednesday: B asic physical effects\, squeezing\, cooling\, entanglement\n\n------------ ----------------------------------------\n\nLecture Abstract: \n\nThe tail of a comet always points away from the sun. Back in the 17th century\, K epler explained this observation proposing that light exerts a force on ma tter\, the so-called radiation pressure force. Four hundred years later t echnological progress has allowed studying this force in a completely diff erent playground: high-finesse cavities allow to concentrate very high ra diation intensities on lightweight mechanical devices that are exceptional ly well shielded from the neighbouring environment. In these cavity-optom echanics platforms\, the radiation pressure force can have a strong impact on the mechanical component on a time scale that can be shorter than the typical time for absorbing a single phonon from the environment. This has allowed reaching landmark achievements like cooling a mechanical oscillato r to its ground state\, squeezing the electromagnetic vacuum and measuring gravitational waves. In this series of lectures\, I will give a didactic overview of the field of cavity optomechanics.\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/58/ END:VEVENT BEGIN:VEVENT SUMMARY:Vittorio Peano (Max Planck Institute for the Science of Light) DTSTART:20220120T100000Z DTEND:20220120T113000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/59 DESCRIPTION:Title: Lecture Series on Cavity Optomechanics: From basics concepts to advanced applications\nby Vittorio Peano (Max Planck Institute for the Science of Light) as part of UniKORN seminars\n\n\nAbstract\nThursday: Mu ltimode optomechanics including applications like routers and frequency co nversions\n\n----------------------------------------------------\n\nLectu re Abstract: \n\nThe tail of a comet always points away from the sun. Bac k in the 17th century\, Kepler explained this observation proposing that l ight exerts a force on matter\, the so-called radiation pressure force. F our hundred years later technological progress has allowed studying this f orce in a completely different playground: high-finesse cavities allow to concentrate very high radiation intensities on lightweight mechanical dev ices that are exceptionally well shielded from the neighbouring environmen t. In these cavity-optomechanics platforms\, the radiation pressure force can have a strong impact on the mechanical component on a time scale that can be shorter than the typical time for absorbing a single phonon from t he environment. This has allowed reaching landmark achievements like cooli ng a mechanical oscillator to its ground state\, squeezing the electromagn etic vacuum and measuring gravitational waves. In this series of lectures\ , I will give a didactic overview of the field of cavity optomechanics.\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/59/ END:VEVENT BEGIN:VEVENT SUMMARY:Vittorio Peano (Max Planck Institute for the Science of Light) DTSTART:20220121T100000Z DTEND:20220121T113000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/60 DESCRIPTION:Title: Lecture Series on Cavity Optomechanics: From basics concepts to advanced applications\nby Vittorio Peano (Max Planck Institute for the Science of Light) as part of UniKORN seminars\n\n\nAbstract\nFriday: Nonl inear and topological optomechanics\n\n----------------------------------- -----------------\n\nLecture Abstract: \n\nThe tail of a comet always poin ts away from the sun. Back in the 17th century\, Kepler explained this ob servation proposing that light exerts a force on matter\, the so-called ra diation pressure force. Four hundred years later technological progress h as allowed studying this force in a completely different playground: high -finesse cavities allow to concentrate very high radiation intensities on lightweight mechanical devices that are exceptionally well shielded from t he neighbouring environment. In these cavity-optomechanics platforms\, th e radiation pressure force can have a strong impact on the mechanical comp onent on a time scale that can be shorter than the typical time for absorb ing a single phonon from the environment. This has allowed reaching landma rk achievements like cooling a mechanical oscillator to its ground state\, squeezing the electromagnetic vacuum and measuring gravitational waves. I n this series of lectures\, I will give a didactic overview of the field o f cavity optomechanics.\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/60/ END:VEVENT BEGIN:VEVENT SUMMARY:Amir Youssefi\; Ewold Verhagen (EPFL Lausanne\, Switzerland\; Cent er for Nanophotonics\, AMOLF\, Amsterdam\, The Netherlands) DTSTART:20220202T140000Z DTEND:20220202T150000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/61 DESCRIPTION:Title: Superconducting circuit optomechanics in topological lattices & H ermitian and non-Hermitian topology in nano-optomechanical networks\nb y Amir Youssefi\; Ewold Verhagen (EPFL Lausanne\, Switzerland\; Center for Nanophotonics\, AMOLF\, Amsterdam\, The Netherlands) as part of UniKORN s eminars\n\n\nAbstract\nFrontiers Talk by Amir Youssefi & Introductory Talk by Ewold Verhagen\n\n1) Frontiers Talk by Amir Youssefi:\n\nTitle: Superc onducting circuit optomechanics in topological lattices\n\nAbstract:\nQuan tum optomechanics allows controlling mechanical motion\, via the interacti on with electromagnetic radiation. Over the past decades\, optomechanics h as allowed major progress in the quantum control of engineered mechanical systems ranging from ground-state cooling and entanglement of mechanical o bjects to precise position measurements. Yet\, nearly all prior schemes ha ve employed single- or few mode optomechanical systems. In contrast\, nove l dynamics and applications are expected when utilizing optomechanical arr ays and lattices.\n\nSuperconducting circuits are a promising platform to realize optomechanics with a flexible design and precise control. To date\ , however\, realizing optomechanical lattices has been compounded by the l imited scaling in contemporary circuit optomechanics.\nIn this talk\, I ex plain how we overcome this challenge to realize superconducting circuit op tomechanical lattices. We demonstrated non-trivial topological modes in a 10 site optomechanical chain as well as a 24 site honeycomb lattice\, real izing the well-known Su-Schrieffer-Heeger (SSH) model. Furthermore\, I pre sent a technique exploiting embedded optomechanical interaction to directl y measure the collective microwave modeshape\, without using any local pro be or inducing perturbation. Our new platform accompanied by the measureme nt techniques introduced offers an avenue to explore many-body physics in optomechanical lattices such as quantum and classical collective dynamics\ , quantum entanglement\, and topological behaviors to name a few.\n\n\n\n2 ) Introductory Talk by Ewold Verhagen:\n\nTitle: Hermitian and non-Hermiti an topology in nano-optomechanical networks\n\nAbstract: The toolbox of op tomechanical interactions yields powerful new ways to control the flow of photons and phonons\, in systems that involve more than a single optical a nd mechanical mode. Suitable laser fields can couple these degrees of free dom\, creating bosonic networks that can be reconfigured at will\, and imb uing unusual behavior that cannot be found in regular\, passive photonic o r phononic systems. The fact that optomechanical control fields can readil y convert frequencies allows the effective breaking of time-reversal symme try\, leading to nonreciprocal behavior like isolation and circulation. We study how the created synthetic magnetic fields in optomechanical network s lead to states and transport behavior that mimics the quantum Hall effec t for electrons – a canonical form of a topological insulator. Interesti ngly\, the fact that optomechanical interactions can additionally induce n onlinearity as well as controlled gain and loss (non-Hermiticity) leads to behavior that does not have counterparts in electronic materials. Specifi cally\, we show that the introduction of optomechanical squeezing in nanom echanical networks with broken time-reversal symmetry leads to new types o f synthetic gauge fields\, that control the non-Hermitian dynamics of the networks in unusual ways. They could form the building blocks of novel non -Hermitian topological phases with applications in topological amplifiers and nanomechanical sensing.\n\nChaired by Clara Wanjura.\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/61/ END:VEVENT BEGIN:VEVENT SUMMARY:Tirth Shah\; Aash Clerk (Max Planck Institute for the Science of L ight\, Erlangen\, Germany\; University of Chicago\, USA) DTSTART:20220216T140000Z DTEND:20220216T150000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/62 DESCRIPTION:Title: Topological phonon transport in an optomechanical system\; Non-He rmitian quantum dynamics: from sensing to non-equilibrium steady states\nby Tirth Shah\; Aash Clerk (Max Planck Institute for the Science of Li ght\, Erlangen\, Germany\; University of Chicago\, USA) as part of UniKORN seminars\n\n\nAbstract\nTalks by Tirth Shah & Aash Clerk\n\n1) Tirth Shah \n\nTitle: Topological phonon transport in an optomechanical system\n\nAbs tract: Recent advances in cavity optomechanics have now made it possible t o use light to measure mechanical motion down to the individual phonons. A t the same time\, microfabrication techniques have enabled small-scale on- chip optomechanical circuits. Motivated by these developments\, several th eoretical works have envisioned larger scale optomechanical systems where light is used to steer and detect on-chip topological vibrations. In this talk\, I will present our work [1] on the observation of topological phono n transport within a multiscale optomechanical crystal structure consistin g of an array of over 800 cavity-optomechanical elements. Using sensitive\ , spatially resolved optical read-out\, we detect thermal phonons in a 0.3 25−0.34 GHz band traveling along a topological edge channel\, with subst antial reduction in backscattering. This work further advances the ongoing effort to miniaturize topological phononic devices down to the nanoscale\ , opening the way to GHz frequency acoustic wave circuits comprising robus t delay lines and non-reciprocal elements.\n\n[1] Ren\, H.\, Shah\, T.\, P feifer\, H.\, Brendel\, C.\, Peano\, V.\, Marquardt\, F.\, & Painter\, O. (2020). Topological phonon transport in an optomechanical system. arXiv pr eprint arXiv:2009.06174.\n\n2) Aash Clerk\n\nTitle: Non-Hermitian quantum dynamics: from sensing to non-equilibrium steady states\n\nAbstract: Exte nded lattice systems where the propagation of waves or particles is descri bed by an effective non-Hermitian Hamiltonian can exhibit a myriad of unus ual properties\, including a dramatic sensitivity to boundary conditions. This effect (known as the “non-Hermitian skin effect”) goes beyond th e standard bulk-boundary correspondence of conventional topological syste ms. The non-Hermitian dynamics required here ultimately corresponds to re alizing structured loss and gain processes that yield directional dynamics \, and hence is within reach of several optomechanical platforms. In this talk\, I’ll give an introduction to some of the basic ideas in this fie ld\, and discuss recent work on how these effects manifest themselves in f ully quantum settings. I’ll discuss both an application to enhanced qua ntum parameter sensing (where one can enhance sensitivity exponentially wi th the length of the lattice)\, and work discussing how these non-Hermitia n effective Hamiltonians can yield surprising kinds of non-thermal equilib rium steady states.\n\nChaired by Clara Wanjura.\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/62/ END:VEVENT BEGIN:VEVENT SUMMARY:Michael Vanner (Imperial College London) DTSTART:20220309T140000Z DTEND:20220309T150000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/63 DESCRIPTION:Title: Brillouin optomechanics in whispering-gallery-mode microresonator s:\nby Michael Vanner (Imperial College London) as part of UniKORN sem inars\n\n\nAbstract\nBackward Brillouin scattering in whispering-gallery-m ode micro-resonators offers an exciting avenue to pursue both classical an d quantum optomechanics applications. Our team—the Quantum Measurement L ab—together with our collaborators\, are currently exploring this regime and the favourable properties it affords for non-Gaussian motional state preparation of the acoustic field. In particular\, the high mechanical fre quencies\, mechanical mode selectivity\, and low optical absorption provid e a promising route to overcome current hindrances within optomechanics. T hree of our recent results in this area include: the observation of Brillo uin optomechanical strong coupling [1]\, single-phonon addition and subtra ction to a thermal state of the acoustic field [2]\, and advancing the sta te-of-the-art of mechanical state tomography to observe the non-Gaussian s tates generated by single- and multi-phonon subtraction [3]. This talk wil l cover these three results\, what they enable\, and the broader direction of our lab including the prospects of this platform for quantum-memory ap plications.\n\nWeb: www.qmeas.net\n\n[1] G. Enzian et al. Optica 6\, 7 (20 19).\n\n[2] G. Enzian et al. Phys. Rev. Lett. 126\, 033601 (2021).\n\n[3] G. Enzian\, L. Freisem\, J. J. Price\, A. Ø. Svela et al. Phys. Rev. Lett . 127\, 243601 (2021).\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/63/ END:VEVENT BEGIN:VEVENT SUMMARY:Niccolò Fiaschi\; Andrei Rakhubovskiy (TU Delft\, Palacký Univer sity) DTSTART:20220316T140000Z DTEND:20220316T150000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/64 DESCRIPTION:Title: Routing quantum information via optomechanical devices & Optimal generation and detection of nonclassical correlations in levitated optomec hanics\nby Niccolò Fiaschi\; Andrei Rakhubovskiy (TU Delft\, Palacký University) as part of UniKORN seminars\n\n\nAbstract\n*TALK ONE* by Nicc olo Fiaschi\n\nTitle: Routing quantum information via optomechanical devic es\n\n\nAbstact: Using acoustic phonons -- quantized traveling mechanical wavepackets -- as a medium to transmit quantum states is currently gaining significant attention\, due to the orders-of-magnitude lower energy phono ns require compared to other carriers\, such as electrons or optical photo ns. Moreover\, phonons are highly promising candidates to connect heteroge neous quantum systems on a chip\, such as microwave and optical photons\, potentially enabling long distances transmission of the quantum states of microwave-frequency quantum systems via optical fibers.\n\n In this talk w e describe the latest works in the Groeblacher Laboratories in TU Delft\, a Optomechanical Quantum Teleportation for long distance quantum repeaters and On-Chip Phononic Distribution of Quantum Information for short distan ce routing.\n\n*TALK TWO* by Andrei Rakhubovskiy\n\n\nTitle: Optimal gener ation and detection of nonclassical correlations in levitated optomechanic s\n\nAbstract: Nonclassical correlations provide a resource for many appli cations in quantum technology\nas well as providing strong evidence that a system is indeed operating in the quantum regime.\nOptomechanical systems can be arranged to generate quantum entanglement between the mechanics an d a mode of traveling light.\nHere we propose automated optimization of th e production of quantum correlations in such a system\, beyond what can be achieved through analytical methods\, by applying Bayesian optimization t o the control parameters.\nFurthermore\, by adding the temporal profile of the detected light modes to the parameter space\, we observe an increase in the magnitude of the correlations.\nThis indicates the importance of ac curate designation of the light modes of interest for the detection of the correlations.\nWe also observe that our optimization approach finds param eters that allow significant squeezing in the high-temperature regime.\nTh is extends the range of experimental setups in which non-classical correla tions could be generated beyond the region of high quantum cooperativity.\ n LOCATION:https://researchseminars.org/talk/UniKORNseminars/64/ END:VEVENT BEGIN:VEVENT SUMMARY:Christopher Baker\; Swati Singh\; (University of Queensland\; Univ ersity of Delaware\;) DTSTART:20220406T130000Z DTEND:20220406T140000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/67 DESCRIPTION:Title: Superfluid Optomechanics: Optomechanics with superfluid helium fi lms & Searching for dark matter and dark energy with mechanical systems\nby Christopher Baker\; Swati Singh\; (University of Queensland\; Univer sity of Delaware\;) as part of UniKORN seminars\n\n\nAbstract\nEarly Caree r Researcher talk by Christopher Baker -\nTitle: Optomechanics with superf luid helium films\n\nAbstract: Cavity optomechanics focuses on the interac tion between confined light and a mechanical degree of freedom. Vibrationa l modes of superfluid helium-4 are an attractive mechanical element for c avity optomechanics\, thanks to their low dissipation arising from superfl uid’s viscosity-free flow. Our approach to superfluid optomechanics is based on nanometer-thick films of superfluid helium which self-assemble o n the surface of a microscale optical resonator inside a cryostat. Excitat ions within the film\, known as third sound\, manifest as surface thickne ss waves with a restoring force provided by the van der Waals interaction. These excitations\, by changing the amount of superfluid in the optical m ode’s evanescent field\, modulate the effective path length of the optic al cavity\, thereby providing a dispersive coupling between the superfluid motion and the light confined inside the optical resonator.\n\nLeveraging this optomechanical coupling mechanism\, we have previously shown laser-c ooling and amplification of the superfluid thermal motion [1]\, observatio n of quantized vortex dynamics in a superfluid helium film [2]\, as well a s highly efficient Brillouin lasers [3]. In this talk\, I will give a rapi d overview of our experimental platform\, and present recent developments where we optimize the superfluid fountain-pressure interaction to provide strong dynamical backaction. With this\, we show optically-driven regenera tive oscillation of a 7 mg effective mass superfluid acoustic mode\, with a phonon lasing threshold power of only 3 pW\, corresponding to less than one intracavity photon [4]. I will also show how this superfluid functiona lity can be packaged into an alignment-free\, plug-and-play package requir ing only fiber-optic access in a conventional cryostat\, through the use o f silicon-on-insulator photonic circuits.\n\n[1] G. Harris\, et al.\, Natu re Physics 12 788 (2016).\n\n[2] Y. Sachkou et al.\, Science 366 6472 (201 9) \; S. Forstner et al\, New J. Phys 21 053029 (2019)\n\n[3] X. He\, et a l\, Nature Physics\, 16 4 (2020) \; G. Harris\, et al.\, Opt. Express 28 2 2450 (2020). [4] A. Sawadsky et al\, in preparation\, (2022) \; W. Wasserm an et al\, in preparation\, (2022)\n\n------------------------------------ -------------------------------------------------------\n\nIntroductory ta lk by Swati Singh -\nTitle: Searching for dark matter and dark energy with mechanical systems\n\nAbstract: The coupling of normal\, Standard Model m atter with dark matter or dark energy sometimes manifests itself as a mech anical effect: strain\, recoil kicks\, or acceleration. Following a review of the expected mechanical signature\, I will discuss the feasibility of searching for ultralight dark matter using various optomechanical systems\ , highlighting the unique advantages of superfluid-based optomechanical sy stems. I will also show that current mechanical systems have the sensitivi ty to set new constraints on scalar field candidates for dark energy. Fina lly\, I will briefly overview the promise of quantum noise limited detecto rs in the search for beyond the standard model physics.\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/67/ END:VEVENT BEGIN:VEVENT SUMMARY:Xavier Rojas\; John Davis\; (Royal Holloway\, University of London \; University of Alberta\;) DTSTART:20220413T140000Z DTEND:20220413T150000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/68 DESCRIPTION:Title: Superfluid Optomechanics with Phononic Nanostructures & Superflu id Helium Electromechanics\nby Xavier Rojas\; John Davis\; (Royal Holl oway\, University of London\; University of Alberta\;) as part of UniKORN seminars\n\n\nAbstract\nTalk 1- Xavier Rojas\n\nTitle: Superfluid Optomech anics with Phononic Nanostructures\n\nAbstract: In quantum optomechanics\ , finding materials and strategies to limit losses has been crucial to the progress of the field. Recently\, superfluid 4He was proposed as a promis ing mechanical element for quantum optomechanics. This quantum fluid shows highly desirable properties (e.g.\, extremely low acoustic loss) for a qu antum optomechanical system. In current implementations\, superfluid optom echanical systems suffer from external sources of loss\, which spoils the quality factor of resonators. In this work1\, we propose an alternate impl ementation\, exploiting nanofluidic confinement. Our approach\, based on a coustic resonators formed within phononic nanostructures\, aims at limitin g radiation losses to preserve the intrinsic properties of superfluid 4He. Using recent theory\, we derive the expected quality factors for acoustic resonators in different thermodynamic conditions. We calculate the source s of loss induced by the phononic nanostructures with numerical simulation s. Our results indicate the feasibility of the proposed approach in a broa d range of parameters\, which opens prospects for more complex geometries. \n\n------------------------------------------------------------\n\nTalk 2 - John Davis\n\nTitle: Superfluid Helium Electromechanics \n\nAbstract: Li quid helium possess many properties that make it an attractive medium for studies of mechanical systems in the quantum regime\, such as low mechanic al and dielectric losses. The flip side of this is to imagine using optom echanics or electromechanics to revisit the novel physics of superfluid he lium\, including bosonic helium-4 and fermionic helium-3. In particular\, when spatially restricted in one dimension\, helium superfluids are expec ted to demonstrate quasi-two dimensional behavior with qualitatively diffe rent physics than in three dimensions. By using nanofabrication technique s to both confine the helium and provide an electromechanical detection sc heme\, we are beginning the journey of studying such two-dimensional super fluids.\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/68/ END:VEVENT BEGIN:VEVENT SUMMARY:Martin Frimmer\, Alexander Eichler (ETH Zurich) DTSTART:20220518T130000Z DTEND:20220518T140000Z DTSTAMP:20260422T225926Z UID:UniKORNseminars/69 DESCRIPTION:Title: Parametron optomechanics\nby Martin Frimmer\, Alexander Eichl er (ETH Zurich) as part of UniKORN seminars\n\n\nAbstract\nTALK 1 ABSTRACT :\n\nTitle: Optically levitated parametric oscillators\n\nAbstract: The ce nter-of-mass degrees of freedom of an optically levitated nanoparticle rep resent harmonic oscillators which lend themselves to studying and exploiti ng the effects of parametric modulation. We discuss the parametric couplin g between two such oscillation modes and its formal connection to the phys ics of a quantum mechanical two-level system. Furthermore\, we introduce t he parametron\, an oscillator-based logic element\, implemented with a lev itated oscillator. We introduce different schemes for switching the parame tron’s logical state and discuss limitations of speed and fidelity.\n\n- ----------------\n\nTALK 2 ABSTRACT:\n\nTitle: Building Ising machines fro m coupled parametric oscillators\n\nKerr parametric resonators\, or simply parametrons\, are driven nonlinear systems whose stable solutions can\, t o some approximation\, be mapped to the two polarization states (up/down) of a spin. Networks of coupled parametrons are being studied as a way to f ind the ground state of Ising Hamiltonians through simulation\, and beyond that for artificial neural networks. However\, coupled nonlinear oscillat ors exhibit phenomena beyond those of a real spin system\, and offer thems elves as a fascinating system to study new physics. In this seminar\, we w ill understand the complex phase diagram that unfolds even in the (seeming ly) simple case of a two-parametron network. I will offer my personal outl ook towards building Ising simulation machines from parametrons\, and how this ambitious endeavor may succeed in spite of considerable challenges.\n LOCATION:https://researchseminars.org/talk/UniKORNseminars/69/ END:VEVENT END:VCALENDAR