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BEGIN:VEVENT
SUMMARY:William Witczak-Krempa (Université de Montréal)
DTSTART:20200930T193000Z
DTEND:20200930T203000Z
DTSTAMP:20260404T111331Z
UID:quanTASeminar/1
DESCRIPTION:Title: Conformal field theories and quantum phase transitions: an en
tanglement perspective\nby William Witczak-Krempa (Université de Mont
réal) as part of quanTA Seminar\n\n\nAbstract\nQuantum phase transitions
occur when a quantum system undergoes a sharp change in its ground state\,
e.g. between a ferro- and para-magnet. I will present a remarkable set of
transitions\, called quantum critical\, that are described by conformal f
ield theories (CFTs). I will focus on 2 and 3 spatial dimensions\, where t
he conformal symmetry is powerful yet less constraining than in 1 dimensio
n. We will probe these scale-invariant theories via the structure of their
quantum entanglement. The methods will include large-N expansions\, the A
dS/CFT duality from string theory\, and large-scale numerical simulations.
Finally\, we’ll see that certain quantum Hall states\, which are topolo
gical in nature\, possess very similar entanglement properties. This hints
at broader principles that relate very different quantum states.\n
LOCATION:https://stable.researchseminars.org/talk/quanTASeminar/1/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Monica Jinwoo Kang (Caltech)
DTSTART:20201104T213000Z
DTEND:20201104T223000Z
DTSTAMP:20260404T111331Z
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-dime
nsional analog of the HaPPY code as a growing series of stabilizer codes d
efined respective to their Hilbert spaces. These Hilbert spaces are relate
d by isometries that will be defined during this talk. I will analyze its
system in various aspects and discuss its implications in AdS/CFT. Our res
ult hints that the relevance of quantum error correction in quantum gravit
y may not be limited to the CFT context.\n
LOCATION:https://stable.researchseminars.org/talk/quanTASeminar/2/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Anton Kapustin (Caltech)
DTSTART:20201209T203000Z
DTEND:20201209T213000Z
DTSTAMP:20260404T111331Z
UID:quanTASeminar/3
DESCRIPTION:Title: The topology and geometry of the space of gapped lattice syst
ems\nby Anton Kapustin (Caltech) as part of quanTA Seminar\n\n\nAbstra
ct\nRecently there has been a lot of progress in classifying phases of gap
ped quantum many-body systems. From the mathematical viewpoint\, a phase o
f a quantum system is a connected component of the “space” of gapped q
uantum systems\, and it is natural to study the topology of this space. I
will explain how to probe it using generalizations of the Berry curvature.
I will focus on the case of lattice systems where all constructions can b
e made rigorous. Coarse geometry plays an important role in these construc
tions.\n
LOCATION:https://stable.researchseminars.org/talk/quanTASeminar/3/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Karen Yeats (University of Waterloo)
DTSTART:20210122T213000Z
DTEND:20210122T223000Z
DTSTAMP:20260404T111331Z
UID:quanTASeminar/4
DESCRIPTION:Title: Combinatorial structures in perturbative quantum field theory
\nby Karen Yeats (University of Waterloo) as part of quanTA Seminar\n\
n\nAbstract\nI will give an overview of a few places where combinatorial s
tructures have an interesting role to play in quantum field theory and whi
ch I have been involved in to varying degrees\, from the Connes-Kreimer Ho
pf algebra and other renormalization Hopf algebras\, to the combinatorics
of Dyson-Schwinger equations and the graph theory of Feynman integrals.\n
LOCATION:https://stable.researchseminars.org/talk/quanTASeminar/4/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Igor Boettcher (University of Alberta)
DTSTART:20210317T203000Z
DTEND:20210317T213000Z
DTSTAMP:20260404T111331Z
UID:quanTASeminar/5
DESCRIPTION:Title: Crystallography of hyperbolic lattices: from children's drawi
ngs to Fuchsian groups\nby Igor Boettcher (University of Alberta) as p
art of quanTA Seminar\n\n\nAbstract\nHyperbolic lattices are tessellations
of the hyperbolic plane using\, for instance\, heptagons or octagons. The
y are relevant for quantum error correcting codes and experimental simulat
ions of quantum physics in curved space. Underneath their perplexing beaut
y lies a hidden and\, perhaps\, unexpected periodicity that allows us to i
dentify the unit cell and Bravais lattice for a given hyperbolic lattice.
This paves the way for applying powerful concepts from solid state physics
and\, potentially\, finding a generalization of Bloch's theorem to hyperb
olic lattices. In my talk\, I will explain some of the mathematics underly
ing this hyperbolic crystallography.\n
LOCATION:https://stable.researchseminars.org/talk/quanTASeminar/5/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Maria Emelianenko (George Mason University)
DTSTART:20210414T203000Z
DTEND:20210414T213000Z
DTSTAMP:20260404T111331Z
UID:quanTASeminar/6
DESCRIPTION:Title: Random walks and graphs in materials\, biology\, and quantum
information science\nby Maria Emelianenko (George Mason University) as
part of quanTA Seminar\n\n\nAbstract\nWhat does mathematics\, materials s
cience\, biology\, and quantum information science have in common? It turn
s out\, there are many connections worth exploring. I this talk\, I will f
ocus on graphs and random walks\, starting from the classical mathematical
constructs and moving on to quantum descriptions and applications. We wil
l see how the notions of graph entropy and KL divergence appear in the con
text of characterizing polycrystalline material microstructures and predic
ting their performance under mechanical deformation\, while also allowing
to measure adaptation in cancer networks and entanglement of quantum state
s. We will discover unified conditions under which master equations for cl
assical random walks exhibit nonlocal and non-diffusive behavior and see h
ow quantum walks allow to realize the coveted exponential speedup in quant
um Hamiltonian simulations. Recent classical and quantum breakthroughs and
open questions will be discussed.\n
LOCATION:https://stable.researchseminars.org/talk/quanTASeminar/6/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jonas Fransson (Uppsala University)
DTSTART:20220927T213000Z
DTEND:20220927T223000Z
DTSTAMP:20260404T111331Z
UID:quanTASeminar/7
DESCRIPTION:Title: A correlated view of chiral-induced spin selectivity\nby
Jonas Fransson (Uppsala University) as part of quanTA Seminar\n\nLecture h
eld in PHYS 103.\n\nAbstract\nChiral-induced spin selectivity is an intrig
uing phenomenon that\, to our knowledge\, rests on a foundation of structu
ral chirality\, spin-orbit interactions\, and strongly nonequilibrium cond
itions. The effect is a measure of the response to changes in the magnetic
environment coupled to the active region\, and the phenomenology refers b
ack to the experimental observations of substantial changes in the charge
current amplitude through chiral molecules upon changes in the external ma
gnetic conditions. Chiral-induced spin selectivity has been shown to not b
e limited to multistranded helical structures\, such as double-stranded DN
A molecules and bacteriorhodopsin\, but has also been observed in\, for ex
ample\, various types of peptides and polyalanines and\, recently\, also i
n helicene.\n\nIn order to depart from the generic single electron\, or\,
non-interacting models that have\, quite unsuccessfully\, been used in att
empts to describe the chiral-induced spin selectivity effect\, it is propo
ses to include many-body effects\, arising from\, e.g.\, electron-electron
or electron-vibron interactions. In cooperation with spin-orbit interacti
ons\, the many-body interactions generate exchange splitting between the s
pin channels which is viable for the chiral-induced spin selectivity pheno
menon. By constructing models comprising either electron-electron or elect
ron-vibron interactions\, it can be demonstrated that the chiral-induced s
pin selectivity effect increases by several orders of magnitude compared t
o the results from any non-interacting description. The phenomenology of t
he chiral-induced spin selectivity effect indicates that charge transfer w
ithin the chiral molecule is accompanied by the emergence of intra-molecul
ar spin-polarization.\n\n \n\n \n\nSome relevant references:\n\n \n\nJ. Fr
ansson\, Chirality induced spin-selectivity: The role of electron correlat
ion: J Phys Chem Lett\, 10\, 7126 (2019).\n\nJ. Fransson\, Vibrational ori
gin of exchange splitting and chiral-induced spin selectivity: Phys Rev B\
, 102\, 235416 (2020).\n\nJ. Fransson\, Charge Redistribution and Spin Pol
arization Driven by Correlation Induced Electron Exchange in Chiral Molecu
les: Nano Lett\, 21\, 3026 (2021).\n\nJ. Fransson\, Charge and Spin Dynami
cs and Enantioselectivity in Chiral Molecules: J Phys Chem Lett\, 13\, 808
(2022).\n\nIn-person only on University of Saskatchewan campus in room PH
YS 103.\n
LOCATION:https://stable.researchseminars.org/talk/quanTASeminar/7/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Gordon Sarty (University of Saskatchewan)
DTSTART:20230124T213000Z
DTEND:20230124T223000Z
DTSTAMP:20260404T111331Z
UID:quanTASeminar/8
DESCRIPTION:Title: MRI as an example of quantum engineering\nby Gordon Sarty
(University of Saskatchewan) as part of quanTA Seminar\n\nLecture held in
PHYSICS 103.\n\nAbstract\nThe term quantum engineering generally focuses
around the design of quantum computers\, but MRI is an excellent example o
f quantum mechanics applied to engineering. It works by exciting proton sp
ins in water molecules in a patient's body\, spatially encoding them by ph
ase according to systematic applications of RF pulses and magnetic field c
onfigurations. The engineering needed is both old and new. On one hand\, a
n application of simple Ham radio technology is used to make the small MRI
prototypes now in my lab. This direction will hopefully lead to a prolife
ration of MRIs to nearly every medical clinic situation around the world.
On the other hand\, the use of new quantum materials - which is definitely
not Ham radio technology - promises MRI designs that are ever smaller\, c
onceptually different in function and more sensitive. In this lecture\, I
will talk about both the small simple MRIs that I am building now and abou
t the work we have been doing with diamonds as a quantum material to serve
as very sensitive magnetometers for application to future MRI designs.\n\
nHybrid delivery (in person on University of Saskatchewan campus and via Z
oom).\n
LOCATION:https://stable.researchseminars.org/talk/quanTASeminar/8/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Artur Sowa (University of Saskatchewan)
DTSTART:20220125T213000Z
DTEND:20220125T223000Z
DTSTAMP:20260404T111331Z
UID:quanTASeminar/9
DESCRIPTION:Title: New application of harmonic analysis to quantum theory and en
gineering\nby Artur Sowa (University of Saskatchewan) as part of quanT
A Seminar\n\n\nAbstract\nHarmonic analysis has played a foundational role
in quantum theory all throughout its historical development.\nTo recall a
few well-known examples\, it is expressly present in the Heisenberg uncert
ainty principle (1920s)\; it\nwas fundamental in solving the quantum spin
chain (1970s)\; it now helps to gain insights into the problem of\nquantum
ness in relation to quantum computing (2010s). While sourcing some of its
methods from the repertoire\nof harmonic analysis\, Physics has always gen
erously paid back\, e.g.\, the coherent state theory stimulated the\ndevel
opment of wavelet techniques and of the linear canonical transform. In thi
s talk I will highlight some\nlesser-known recent examples of quantum appl
ications of harmonic analysis. In particular\, I will demonstrate\nhow the
Haar transform (i.e.\, a special type of wavelet transform) helps to anal
yze the dynamics of an array of\nqubits. I will also highlight application
s of the generalized Fourier transform on the multiplicative group of\npos
itive rationals (i.e.\, the group furnished by the multiplication of commo
n fractions) to the analysis of arrays\nof bosons. The ultimate purpose of
this work is to help countervail the so-called “curse of dimensionality
”\nwhich arises in quantum engineering and other aspects of quantum theo
ry and modelling. The outcomes that I\nwill relay serve as good examples o
f value being added (and multiplied) when mathematicians and physicists\ne
xchange ideas. The tools that were inspired by these collaborative efforts
help tackle more general problems of\noperator analysis. They also highli
ght some mesmerizing new connections between quantum theory and the\nanaly
tic number theory as well as fractals.\n
LOCATION:https://stable.researchseminars.org/talk/quanTASeminar/9/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Steven Rayan (University of Saskatchewan)
DTSTART:20220215T213000Z
DTEND:20220215T223000Z
DTSTAMP:20260404T111331Z
UID:quanTASeminar/10
DESCRIPTION:Title: New models of quantum matter inspired by geometry\nby St
even Rayan (University of Saskatchewan) as part of quanTA Seminar\n\nLectu
re held in PHYS 103.\n\nAbstract\nThe exciting and rapidly-growing field o
f topological materials has brought with it unexpected new connections\nbe
tween physics and mathematics. As the name suggests\, topology has played
a significant role in\nunderstanding and classifying these materials. In t
his talk\, I will offer a brief look at another emerging chapter\nin this
story in which exotic geometries — of the kind found in the woodcuts of
M.C. Escher! — anticipate new\nmodels of two-dimensional quantum matter
associated with hyperbolic lattices.\n\nIn-person only on University of Sa
skatchewan campus in room PHYS 103.\n
LOCATION:https://stable.researchseminars.org/talk/quanTASeminar/10/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Matthew Rupert (University of Saskatchewan)
DTSTART:20230306T220000Z
DTEND:20230306T233000Z
DTSTAMP:20260404T111331Z
UID:quanTASeminar/11
DESCRIPTION:Title: Recent progress on the Kazhdan-Lusztig correspondence for ve
rtex operator algebras and quantum groups\nby Matthew Rupert (Universi
ty of Saskatchewan) as part of quanTA Seminar\n\nLecture held in PHYSICS 1
26.\n\nAbstract\nVertex operator algebras are the symmetry algebras of two
dimensional conformal field theory. In a famous series of papers\, Kazhda
n and Lusztig proved an equivalence between particular semi-simple categor
ies of modules over affine Lie algebras and quantum groups\, the former of
which can also be realized as modules over a corresponding vertex operato
r algebra. Such equivalences between representation categories of vertex o
perator algebras and quantum groups are now broadly referred to as the Kaz
hdan-Lusztig correspondence.\n\nThere has been substantial research intere
st over the last two decades in understanding the Kazhdan-Lusztig correspo
ndence for vertex operator algebras with non semi-simple representation th
eory. In this talk I will present recent categorical results which aid in
proving such equivalences with applications to the singlet vertex algebra
in particular. Based on joint work with Thomas Creutzig and Simon Lentner.
\n\nTalk is hybrid with in-person audience in room PHYSICS 126 on the Univ
ersity of Saskatchewan campus with a simultaneous virtual stream on Zoom.\
n
LOCATION:https://stable.researchseminars.org/talk/quanTASeminar/11/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Thomas Chen (UT Austin)
DTSTART:20230310T203000Z
DTEND:20230310T213000Z
DTSTAMP:20260404T111331Z
UID:quanTASeminar/12
DESCRIPTION:Title: On the emergence of Boltzmann equations from quantum dynamic
s\nby Thomas Chen (UT Austin) as part of quanTA Seminar\n\n\nAbstract\
nThe mathematically rigorous derivation of nonlinear Boltzmann equations f
rom first principles in interacting physical systems is an extremely activ
e research area in Analysis\, Mathematical Physics\, and Applied Mathemati
cs. In classical physical systems\, rigorous results of this type have bee
n obtained for some models. In the quantum case on the other hand\, the pr
oblem has essentially remained open. In this talk\, I will explain how a c
ubic quantum Boltzmann equation arises within the fluctuation dynamics aro
und a Bose-Einstein condensate\, within the quantum field theoretic descri
ption of an interacting Boson gas. This is based on joint work with Michae
l Hott.\n\nVirtual talk held in conjunction with the Mathematics & Statist
ics Colloquium at the University of Saskatchewan.\n
LOCATION:https://stable.researchseminars.org/talk/quanTASeminar/12/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sean Lawton (George Mason University)
DTSTART:20230712T203000Z
DTEND:20230712T214500Z
DTSTAMP:20260404T111331Z
UID:quanTASeminar/13
DESCRIPTION:Title: What is a character variety?\nby Sean Lawton (George Mas
on University) as part of quanTA Seminar\n\nLecture held in St. Thomas Mor
e 1002.\n\nAbstract\nCharacter varieties are topological spaces that are a
playground for intermingling areas of mathematics and science. In this t
alk\, I will give a definition that unifies many approaches to them\, disc
uss areas of study where they naturally arise\, and give examples requirin
g little more than linear algebra to understand. There will be pictures.\
n\nIn-person only on University of Saskatchewan campus in room St. Thomas
More 1002.\n
LOCATION:https://stable.researchseminars.org/talk/quanTASeminar/13/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Lindsay LeBlanc (University of Alberta)
DTSTART:20231128T213000Z
DTEND:20231128T223000Z
DTSTAMP:20260404T111331Z
UID:quanTASeminar/14
DESCRIPTION:Title: Light-matter interactions in cold and ultracold neutral atom
ic gases: applications to quantum technologies\nby Lindsay LeBlanc (Un
iversity of Alberta) as part of quanTA Seminar\n\nLecture held in PHYSICS
103.\n\nAbstract\nNeutral atomic gases provide fantastic opportunities for
studying and controlling quantum phenomena\, ranging from many-body physi
cs to quantum computers. In our research\, we use the well-known interacti
ons between cold gases and electromagnetic radiation to harness various qu
antum degrees of freedom. Quantum memories\, used for storing and manipula
ting photonic signals\, will be a key component in quantum communications
systems\, especially in realizing critical quantum repeater infrastructure
. Cold atoms have significant potential as high performance spin-wave quan
tum memories\, due to the long storage times associated with low temperatu
re and slow thermal diffusion. In our work\, we demonstrate two memory pro
tocols in ultracold (sometimes Bose-condensed) atoms\, which hold the pote
ntial for high-performance light storage: the Autler-Townes splitting (ATS
) and superradiant approaches. These methods provide a path towards practi
cal implementations in both ground- and satellite-based quantum communicat
ions systems\, and we are working on both increasing performance and devel
oping practical implementations. In a other directions\, our lab also uses
ultracold ensembles to study unconventional quantum gates for quantum com
puting\, and warm vapours in microwave cavities to exploit simultaneous mi
crowave and optical transitions.\n\nIn-person only on University of Saskat
chewan campus in room PHYSICS 103.\n
LOCATION:https://stable.researchseminars.org/talk/quanTASeminar/14/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Mao Yoshii (Tokyo University)
DTSTART:20240312T213000Z
DTEND:20240312T223000Z
DTSTAMP:20260404T111331Z
UID:quanTASeminar/15
DESCRIPTION:Title: Invitation to heterolayer systems: towards an extension to t
he superconducting phase\nby Mao Yoshii (Tokyo University) as part of
quanTA Seminar\n\nLecture held in PHYSICS 103.\n\nAbstract\nIt has been al
most 20 years since the exfoliation technique for graphene was developed a
t the beginning of this century. Various two-dimensional materials can now
be produced and their properties have been investigated. These thin films
exhibit different properties from their original three-dimensional counte
rpart\, but we can also create new systems by stacking them. In particular
\, in recent years\, the discovery of unconventional superconductivity in
magic-angle twisted bilayer graphene and the improvement of fabrication te
chniques of multilayer systems have increased attention to the superconduc
ting state of heterolayer systems. On the other hand\, thin-film multilaye
r systems are generally quasiperiodic and this makes theoretical studies d
ifficult. For noninteracting systems\, we have the so-called Brillouin Zon
e (BZ) folding method which helps us to study multilayer systems efficient
ly. However\, this method has not been extended to interacting systems. In
this talk\, we will start with a review of the BZ folding method for norm
al-conducting phases and then extend it to superconducting phases.\n\nIn-p
erson only on University of Saskatchewan campus in room PHYSICS 103.\n
LOCATION:https://stable.researchseminars.org/talk/quanTASeminar/15/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Christopher Mahadeo (University of Illinois at Chicago)
DTSTART:20240213T213000Z
DTEND:20240213T223000Z
DTSTAMP:20260404T111331Z
UID:quanTASeminar/16
DESCRIPTION:Title: Something old\, something new\, something borrowed\, and som
ething quantized\nby Christopher Mahadeo (University of Illinois at Ch
icago) as part of quanTA Seminar\n\nLecture held in PHYSICS 103.\n\nAbstra
ct\nRecent work by the quanTA center has pioneered the idea of hyperbolic
band theory\, the mathematical formulation of a new class of quantum mater
ials. In this talk I will discuss how new approaches to classical band the
ory led to this development\, and how techniques borrowed from random matr
ix theory have the potential to produce fascinating results.\n\nIn-person
only on University of Saskatchewan campus in room PHYSICS 103.\n
LOCATION:https://stable.researchseminars.org/talk/quanTASeminar/16/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Barry Sanders (University of Calgary)
DTSTART:20240206T213000Z
DTEND:20240206T223000Z
DTSTAMP:20260404T111331Z
UID:quanTASeminar/17
DESCRIPTION:Title: Kittens\, cats\, and compasses: superposing coherent states
for quantum sensing\, quantum communication\, quantum computing\, and quan
tum fun\nby Barry Sanders (University of Calgary) as part of quanTA Se
minar\n\nLecture held in PHYSICS 103.\n\nAbstract\nGlauber coherent states
are semiclassical in the sense that that follow classical harmonic-oscill
ator dynamics and are minimum-uncertainty states. A superposition of two m
acroscopically distinct coherent states is a Schrödinger cat state (alive
and dead in superposition) and a kitten if not macroscopically distinct.
Superposing two- and multi-mode coherent states is an entangled coherent s
tate. Geometric intuition arises through quasiprobability representations\
, allowing us to talk about superposing coherent states on a line (relevan
t to bosonic qubits) and on a circle (e.g.\, compass states also relevant
to bosonic qubits). I present this potted history followed by our proposal
for making a nuclear cat state: arXiv:2304.13813.\n\nIn-person on Univers
ity of Saskatchewan campus in room PHYSICS 103. (Zoom link reserved for US
ask graduate students who are based off-site or who otherwise cannot atten
d in person.)\n
LOCATION:https://stable.researchseminars.org/talk/quanTASeminar/17/
END:VEVENT
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