BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Itamar Procaccia (Weizmann Institute of Science) DTSTART:20211013T160000Z DTEND:20211013T170000Z DTSTAMP:20260422T225726Z UID:IIPSeminar/1 DESCRIPTION:Title: Anomalous Elasticity and Plastic Screening in Amorphous Solids\nby Itamar Procaccia (Weizmann Institute of Science) as part of Virtual Semina r of the International Institute of Physics\n\n\nAbstract\nIn this lecture I will argue that elasticity theory needs to be fundamentally changed in order to deal with amorphous solids. In a recent paper [Phys. Rev. E 104\, 024904] we showed that mechanical strains in amorphous solids are screen ed via the formation of plastic events that are typically quadrupolar in n ature. At low densities of quadrupoles the screening effect is reminiscen t of the role of dipoles in dielectrics\, while the effect at high density has no immediate electrostatic analog\, and is expected to change qualita tively the mechanical response\, as seen for example in the displacement \ nfield. The phenomenon is akin to a Kosterlitz-Thouless transition as will be explained in this lecture. I will show that high-density screening res ults in undulating displacement \nfields that strictly deviate from elasti city theory. Theoretical analysis\, experimental measurements and numerica l simulations of frictional granular amorphous assemblies are in agreement with each other and provide a strong support for the theory.\n LOCATION:https://researchseminars.org/talk/IIPSeminar/1/ END:VEVENT BEGIN:VEVENT SUMMARY:Antonio Duarte Pereira (Federal Fluminense University) DTSTART:20211020T160000Z DTEND:20211020T170000Z DTSTAMP:20260422T225726Z UID:IIPSeminar/2 DESCRIPTION:Title: Spacetime and matter under the microscope\nby Antonio Duarte Pereir a (Federal Fluminense University) as part of Virtual Seminar of the Intern ational Institute of Physics\n\nAbstract: TBA\n LOCATION:https://researchseminars.org/talk/IIPSeminar/2/ END:VEVENT BEGIN:VEVENT SUMMARY:Thiago Tomei (UNESP) DTSTART:20211103T160000Z DTEND:20211103T170000Z DTSTAMP:20260422T225726Z UID:IIPSeminar/3 DESCRIPTION:Title: BSM and Dark Matter searches in Colliders\nby Thiago Tomei (UNESP) as part of Virtual Seminar of the International Institute of Physics\n\n\n Abstract\nThe search for physics beyond the standard model remains one of the main directives of the LHC experiments. One possible direction for thi s search is the understanding of the "dark matter" phenomena\, a set of as tronomical and cosmological evidences that seem to point in the direction of a hitherto unknown kind of invisible matter. The quest for dark matter profits from the complementarity between direct/indirect detection and col lider experiments. In this talk we will quickly introduce dark matter\, th e LHC and the general-purpose LHC experiments. We will then understand how to search for dark matter in a hadron collider\, and finish with the late st results on dark matter searches from the LHC.\n LOCATION:https://researchseminars.org/talk/IIPSeminar/3/ END:VEVENT BEGIN:VEVENT SUMMARY:Ady Stern (Weizmann Institute of Science) DTSTART:20211110T160000Z DTEND:20211110T170000Z DTSTAMP:20260422T225726Z UID:IIPSeminar/4 DESCRIPTION:Title: Spread and erase - How electron hydrodynamics can eliminate the Landaue r-Sharvin resistance\nby Ady Stern (Weizmann Institute of Science) as part of Virtual Seminar of the International Institute of Physics\n\n\nAbs tract\nIt has long been realized that even a perfectly clean electronic sy stem harbors a Landauer-Sharvin resistance\, inversely proportional to the number of its conduction channels. This resistance is usually associated with voltage drops on the system's contacts to an external circuit. Recent theories have shown that hydrodynamic effects can reduce this resistance\ , raising the question of the lower bound of resistance of hydrodynamic el ectrons. Here we show that by a proper choice of device geometry\, it is p ossible to spread the Landauer-Sharvin resistance throughout the bulk of t he system\, allowing its complete elimination by electron hydrodynamics. W e trace the effect to the dynamics of electrons flowing in channels that t erminate within the sample.\n LOCATION:https://researchseminars.org/talk/IIPSeminar/4/ END:VEVENT BEGIN:VEVENT SUMMARY:Veronika Baumann (Institute for Quantum Optics and Quantum Informa tion) DTSTART:20211117T160000Z DTEND:20211117T170000Z DTSTAMP:20260422T225726Z UID:IIPSeminar/5 DESCRIPTION:Title: Observers in superposition and the quantum measurement problem\nby Veronika Baumann (Institute for Quantum Optics and Quantum Information) as part of Virtual Seminar of the International Institute of Physics\n\n\nAb stract\nThe quantum measurement problem is one of the oldest conceptual pr oblems of quantum theory and based on the fact that (standard) quantum the ory comprises two different dynamics\, namely the collapse of the wave fun ction\, which without any ontological commitment means the application of the state-update rule\, and unitary evolution. Quantum theory\, however\, does not tell us when to use which dynamics\, meaning that it does not spe cify what qualifies some interactions as measurements\, but not others. \n \nWigner’s-friend experiments consider observations of observers in orde r to illustrate the measurement problem. They comprise observers — frien ds — who measure quantum systems\, as well as so-called superobservers – Wigners– who perform joint measurements on the quantum systems\, the friends and potentially other relevant degrees of freedom. The friends de scribe their interactions with the respective quantum systems as measureme nts and\, therefore\, apply the state-update rule\, while the Wigners desc ribe the same interactions unitarily.\n\nIn recent years new proposals inv olving Winger’s friend experiments have been used to devise arguments ag ainst the consistency of quantum theory and the existence of objective\, o bserver-independent facts\, which sparked renewed debate in the quantum-fo undations community. We made a clear distinction between the formalism and the interpretations of quantum theory and showed that there are actually two inequivalent quantum formalisms. If different agents in a Wigner’s-f riend experiment use different formal descriptions for a quantum measureme nt\, they arrive at contradicting statements. This\, however\, becomes man ifest only if there are classical records of these statements that can be compared at some point.\n LOCATION:https://researchseminars.org/talk/IIPSeminar/5/ END:VEVENT BEGIN:VEVENT SUMMARY:Michael Berry (University of Bristol) DTSTART:20211124T160000Z DTEND:20211124T170000Z DTSTAMP:20260422T225726Z UID:IIPSeminar/6 DESCRIPTION:Title: Divergent series: from Thomas Bayes’s bewilderment to today’s resur gence via the rainbow\nby Michael Berry (University of Bristol) as par t of Virtual Seminar of the International Institute of Physics\n\nAbstract : TBA\n LOCATION:https://researchseminars.org/talk/IIPSeminar/6/ END:VEVENT BEGIN:VEVENT SUMMARY:Rodrigo Pereira (International Institute of Physics) DTSTART:20211027T160000Z DTEND:20211027T170000Z DTSTAMP:20260422T225726Z UID:IIPSeminar/7 DESCRIPTION:Title: Majorana fermions bound to line defects in Kitaev spin liquids\nby Rodrigo Pereira (International Institute of Physics) as part of Virtual Se minar of the International Institute of Physics\n\n\nAbstract\nThe field-i nduced Kitaev spin liquid is a strongly correlated topological phase which may have been realized in the layered material alpha-RuCl3. It is charact erized by the presence of gapped non-Abelian anyon excitations in the bulk and gapless chiral Majorana modes at the edges. In this talk I will show that gapless one-dimensional modes can also survive in the bulk of the Kit aev spin liquid when they are bound to line defects at which the exchange interaction falls below a critical value. Treating the weak interaction at the line defect within a mean-field approximation\, we determine the crit ical interaction strength as a function of the external magnetic field. In the gapless regime\, we use the low-energy effective field theory to calc ulate the spin-lattice relaxation rate for a spin near the defect. I will also discuss the relevance of these results to nuclear magnetic resonance experiments that claimed to have observed gapless excitations in the putat ive spin liquid phase of alpha-RuCl3.\n LOCATION:https://researchseminars.org/talk/IIPSeminar/7/ END:VEVENT END:VCALENDAR