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SUMMARY:William Witczak-Krempa (Université de Montréal)
DTSTART;VALUE=DATE-TIME:20200930T193000Z
DTEND;VALUE=DATE-TIME:20200930T203000Z
DTSTAMP;VALUE=DATE-TIME:20220927T054426Z
UID:quanTASeminar/1
DESCRIPTION:Title: Conformal field theories and quantum phase transitions: an entanglem
ent perspective\nby William Witczak-Krempa (Université de Montréal)
as part of quanTA Seminar\n\n\nAbstract\nQuantum phase transitions occur w
hen a quantum system undergoes a sharp change in its ground state\, e.g. b
etween a ferro- and para-magnet. I will present a remarkable set of transi
tions\, called quantum critical\, that are described by conformal field th
eories (CFTs). I will focus on 2 and 3 spatial dimensions\, where the conf
ormal symmetry is powerful yet less constraining than in 1 dimension. We w
ill probe these scale-invariant theories via the structure of their quantu
m entanglement. The methods will include large-N expansions\, the AdS/CFT
duality from string theory\, and large-scale numerical simulations. Finall
y\, we’ll see that certain quantum Hall states\, which are topological i
n nature\, possess very similar entanglement properties. This hints at bro
ader principles that relate very different quantum states.\n
LOCATION:https://researchseminars.org/talk/quanTASeminar/1/
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BEGIN:VEVENT
SUMMARY:Monica Jinwoo Kang (Caltech)
DTSTART;VALUE=DATE-TIME:20201104T213000Z
DTEND;VALUE=DATE-TIME:20201104T223000Z
DTSTAMP;VALUE=DATE-TIME:20220927T054426Z
UID:quanTASeminar/2
DESCRIPTION:Title: The infinite HaPPY code\nby Monica Jinwoo Kang (Caltech) as part
of quanTA Seminar\n\n\nAbstract\nI will construct an infinite-dimensional
analog of the HaPPY code as a growing series of stabilizer codes defined
respective to their Hilbert spaces. These Hilbert spaces are related by is
ometries that will be defined during this talk. I will analyze its system
in various aspects and discuss its implications in AdS/CFT. Our result hin
ts that the relevance of quantum error correction in quantum gravity may n
ot be limited to the CFT context.\n
LOCATION:https://researchseminars.org/talk/quanTASeminar/2/
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BEGIN:VEVENT
SUMMARY:Anton Kapustin (Caltech)
DTSTART;VALUE=DATE-TIME:20201209T203000Z
DTEND;VALUE=DATE-TIME:20201209T213000Z
DTSTAMP;VALUE=DATE-TIME:20220927T054426Z
UID:quanTASeminar/3
DESCRIPTION:Title: The topology and geometry of the space of gapped lattice systems
\nby Anton Kapustin (Caltech) as part of quanTA Seminar\n\n\nAbstract\nRec
ently there has been a lot of progress in classifying phases of gapped qua
ntum many-body systems. From the mathematical viewpoint\, a phase of a qua
ntum system is a connected component of the “space” of gapped quantum
systems\, and it is natural to study the topology of this space. I will ex
plain how to probe it using generalizations of the Berry curvature. I will
focus on the case of lattice systems where all constructions can be made
rigorous. Coarse geometry plays an important role in these constructions.\
n
LOCATION:https://researchseminars.org/talk/quanTASeminar/3/
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SUMMARY:Karen Yeats (University of Waterloo)
DTSTART;VALUE=DATE-TIME:20210122T213000Z
DTEND;VALUE=DATE-TIME:20210122T223000Z
DTSTAMP;VALUE=DATE-TIME:20220927T054426Z
UID:quanTASeminar/4
DESCRIPTION:Title: Combinatorial structures in perturbative quantum field theory\nb
y Karen Yeats (University of Waterloo) as part of quanTA Seminar\n\n\nAbst
ract\nI will give an overview of a few places where combinatorial structur
es have an interesting role to play in quantum field theory and which I ha
ve been involved in to varying degrees\, from the Connes-Kreimer Hopf alge
bra and other renormalization Hopf algebras\, to the combinatorics of Dyso
n-Schwinger equations and the graph theory of Feynman integrals.\n
LOCATION:https://researchseminars.org/talk/quanTASeminar/4/
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BEGIN:VEVENT
SUMMARY:Igor Boettcher (University of Alberta)
DTSTART;VALUE=DATE-TIME:20210317T203000Z
DTEND;VALUE=DATE-TIME:20210317T213000Z
DTSTAMP;VALUE=DATE-TIME:20220927T054426Z
UID:quanTASeminar/5
DESCRIPTION:Title: Crystallography of hyperbolic lattices: from children's drawings to
Fuchsian groups\nby Igor Boettcher (University of Alberta) as part of
quanTA Seminar\n\n\nAbstract\nHyperbolic lattices are tessellations of the
hyperbolic plane using\, for instance\, heptagons or octagons. They are r
elevant for quantum error correcting codes and experimental simulations of
quantum physics in curved space. Underneath their perplexing beauty lies
a hidden and\, perhaps\, unexpected periodicity that allows us to identify
the unit cell and Bravais lattice for a given hyperbolic lattice. This pa
ves the way for applying powerful concepts from solid state physics and\,
potentially\, finding a generalization of Bloch's theorem to hyperbolic la
ttices. In my talk\, I will explain some of the mathematics underlying thi
s hyperbolic crystallography.\n
LOCATION:https://researchseminars.org/talk/quanTASeminar/5/
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BEGIN:VEVENT
SUMMARY:Maria Emelianenko (George Mason University)
DTSTART;VALUE=DATE-TIME:20210414T203000Z
DTEND;VALUE=DATE-TIME:20210414T213000Z
DTSTAMP;VALUE=DATE-TIME:20220927T054426Z
UID:quanTASeminar/6
DESCRIPTION:Title: Random walks and graphs in materials\, biology\, and quantum informa
tion science\nby Maria Emelianenko (George Mason University) as part o
f quanTA Seminar\n\n\nAbstract\nWhat does mathematics\, materials science\
, biology\, and quantum information science have in common? It turns out\,
there are many connections worth exploring. I this talk\, I will focus on
graphs and random walks\, starting from the classical mathematical constr
ucts and moving on to quantum descriptions and applications. We will see h
ow the notions of graph entropy and KL divergence appear in the context of
characterizing polycrystalline material microstructures and predicting th
eir performance under mechanical deformation\, while also allowing to meas
ure adaptation in cancer networks and entanglement of quantum states. We w
ill discover unified conditions under which master equations for classical
random walks exhibit nonlocal and non-diffusive behavior and see how quan
tum walks allow to realize the coveted exponential speedup in quantum Hami
ltonian simulations. Recent classical and quantum breakthroughs and open q
uestions will be discussed.\n
LOCATION:https://researchseminars.org/talk/quanTASeminar/6/
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SUMMARY:Jonas Fransson (Uppsala University)
DTSTART;VALUE=DATE-TIME:20220927T213000Z
DTEND;VALUE=DATE-TIME:20220927T223000Z
DTSTAMP;VALUE=DATE-TIME:20220927T054426Z
UID:quanTASeminar/7
DESCRIPTION:Title: A correlated view of chiral-induced spin selectivity\nby Jonas F
ransson (Uppsala University) as part of quanTA Seminar\n\nLecture held in
PHYS 103.\n\nAbstract\nChiral-induced spin selectivity is an intriguing ph
enomenon that\, to our knowledge\, rests on a foundation of structural chi
rality\, spin-orbit interactions\, and strongly nonequilibrium conditions.
The effect is a measure of the response to changes in the magnetic enviro
nment coupled to the active region\, and the phenomenology refers back to
the experimental observations of substantial changes in the charge current
amplitude through chiral molecules upon changes in the external magnetic
conditions. Chiral-induced spin selectivity has been shown to not be limit
ed to multistranded helical structures\, such as double-stranded DNA molec
ules and bacteriorhodopsin\, but has also been observed in\, for example\,
various types of peptides and polyalanines and\, recently\, also in helic
ene.\n\nIn order to depart from the generic single electron\, or\, non-int
eracting models that have\, quite unsuccessfully\, been used in attempts t
o describe the chiral-induced spin selectivity effect\, it is proposes to
include many-body effects\, arising from\, e.g.\, electron-electron or ele
ctron-vibron interactions. In cooperation with spin-orbit interactions\, t
he many-body interactions generate exchange splitting between the spin cha
nnels which is viable for the chiral-induced spin selectivity phenomenon.
By constructing models comprising either electron-electron or electron-vib
ron interactions\, it can be demonstrated that the chiral-induced spin sel
ectivity effect increases by several orders of magnitude compared to the r
esults from any non-interacting description. The phenomenology of the chir
al-induced spin selectivity effect indicates that charge transfer within t
he chiral molecule is accompanied by the emergence of intra-molecular spin
-polarization.\n\n \n\n \n\nSome relevant references:\n\n \n\nJ. Fransson\
, Chirality induced spin-selectivity: The role of electron correlation: J
Phys Chem Lett\, 10\, 7126 (2019).\n\nJ. Fransson\, Vibrational origin of
exchange splitting and chiral-induced spin selectivity: Phys Rev B\, 102\,
235416 (2020).\n\nJ. Fransson\, Charge Redistribution and Spin Polarizati
on Driven by Correlation Induced Electron Exchange in Chiral Molecules: Na
no Lett\, 21\, 3026 (2021).\n\nJ. Fransson\, Charge and Spin Dynamics and
Enantioselectivity in Chiral Molecules: J Phys Chem Lett\, 13\, 808 (2022)
.\n\nIn-person only on University of Saskatchewan campus in room PHYS 103.
\n
LOCATION:https://researchseminars.org/talk/quanTASeminar/7/
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