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BEGIN:VEVENT
SUMMARY:Jeremias Aguilera Damia (Centro Atomico Bariloche)
DTSTART;VALUE=DATE-TIME:20200504T183000Z
DTEND;VALUE=DATE-TIME:20200504T193000Z
DTSTAMP;VALUE=DATE-TIME:20230208T075543Z
UID:Kadanoff/1
DESCRIPTION:Title: Non-Fermi liquid quantum critical points and IR divergencies\nby Jere
mias Aguilera Damia (Centro Atomico Bariloche) as part of Kadanoff seminar
s\n\n\nAbstract\nThe study of metallic Quantum Critical Points with dynami
cs falling beyond the Fermi Liquid paradigm is well-motivated by experimen
tal observations in Strange Metals. Even from a purely theoretical point o
f view\, the description of these systems by means of a fully consistent Q
FT stands as a challenging task. In this talk\, we describe a particular
Quantum Critical Point displaying Non-Fermi Liquid dynamics\, arising by c
oupling a Fermi Surface to a gapless boson. We extend the description to f
inite temperatures by proposing a mechanism to resolve the singular behavi
or associated to static bosons\, thus leading to a consistent characteriza
tion of the Quantum Critical Region. We also comment on the phenomenologic
al implications of our results.\n
LOCATION:https://researchseminars.org/talk/Kadanoff/1/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Wen Wei Ho (Harvard)
DTSTART;VALUE=DATE-TIME:20200511T183000Z
DTEND;VALUE=DATE-TIME:20200511T193000Z
DTSTAMP;VALUE=DATE-TIME:20230208T075543Z
UID:Kadanoff/2
DESCRIPTION:Title: Interacting phases of matter protected by multiple time-translation symme
tries in quasiperiodically-driven systems\nby Wen Wei Ho (Harvard) as
part of Kadanoff seminars\n\n\nAbstract\nThe discrete time-translation sym
metry of a periodically-driven (Floquet) system allows for the existence o
f novel\, nonequilibrium interacting phases of matter. A well-known exampl
e is the discrete time crystal\, a phase characterized by the spontaneous
breaking of this time-translation symmetry. In this talk\, I will show tha
t the presence of *multiple* time-translation symmetries\, realized by qua
siperiodically driving a system with two or more incommensurate frequencie
s\, leads to a panoply of novel non-equilibrium phases of matter\, both sp
ontaneous symmetry-breaking ("discrete time quasi-crystals") and topologic
al. I will demonstrate that these phases are stable in a long-lived\, 'pre
heating' regime\, by outlining rigorous mathematical results establishing
slow heating at high driving frequencies. As a byproduct\, I will introduc
e the notion of many-body localization (MBL) in quasiperiodically-driven s
ystems.\n
LOCATION:https://researchseminars.org/talk/Kadanoff/2/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Chong Wang (Perimeter Institute)
DTSTART;VALUE=DATE-TIME:20200518T183000Z
DTEND;VALUE=DATE-TIME:20200518T193000Z
DTSTAMP;VALUE=DATE-TIME:20230208T075543Z
UID:Kadanoff/3
DESCRIPTION:Title: A theory of deconfined pseudo-criticality\nby Chong Wang (Perimeter I
nstitute) as part of Kadanoff seminars\n\n\nAbstract\nIt has been proposed
that the deconfined criticality in (2+1)d - the quantum phase transition
between a Neel anti-ferromagnet and a valence-bond-solid (VBS) - may actua
lly be pseudo-critical\, in the sense that it is a weakly first-order tran
sition with a generically long correlation length. The underlying field th
eory of the transition would be a slightly complex (non-unitary) fixed poi
nt as a result of fixed points annihilation. This proposal was motivated b
y existing numerical results from large scale Monte-Carlo simulations as w
ell as conformal bootstrap. However\, an actual theory of such complex fix
ed point\, incorporating key features of the transition such as the emerge
nt SO(5) symmetry\, is so far absent. Here we propose a Wess-Zumino-Witten
(WZW) nonlinear sigma model with level k=1\, defined in 2+ϵ dimensions\,
with target space S^(3+ϵ) and global symmetry SO(4+ϵ). This gives a for
mal interpolation between the deconfined criticality at d=3 and the SU(2)_
1 WZW theory at d=2 describing the spin-1/2 Heisenberg chain. The theory c
an be formally controlled\, at least to leading order\, in terms of the in
verse of the WZW level 1/k. We show that at leading order\, there is a fix
ed point annihilation at d*≈2.77\, with complex fixed points above this
dimension including the physical d=3 case. The pseudo-critical properties
such as correlation length\, scaling dimensions and the drifts of scaling
dimensions as the system size increases\, calculated crudely to leading or
der\, are qualitatively consistent with existing numerics.\n
LOCATION:https://researchseminars.org/talk/Kadanoff/3/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Gabriel Cuomo (EPFL)
DTSTART;VALUE=DATE-TIME:20200601T183000Z
DTEND;VALUE=DATE-TIME:20200601T193000Z
DTSTAMP;VALUE=DATE-TIME:20230208T075543Z
UID:Kadanoff/4
DESCRIPTION:Title: The epsilon expansion meets semiclassics\nby Gabriel Cuomo (EPFL) as
part of Kadanoff seminars\n\n\nAbstract\nIn this talk\, I will study the s
caling dimension of the lightest operator of charge n in the U(1) model at
the Wilson-Fisher fixed point in 4-ε dimensions.\nEven for a perturbativ
ely small fixed point coupling λ\, standard perturbation theory breaks do
wn for sufficiently large λ n. Treating λ n as fixed for small λ\, I wi
ll show that the scaling dimension can be successfully computed through a
semiclassical expansion around a non-trivial trajectory\, resulting in a s
eries in the coupling whose coefficients are fixed functions of λ n. I wi
ll discuss explicitly the computation of the first two orders in the expan
sion. The result\, when expanded at small λ n\, perfectly agrees with all
available diagrammatic computations. The asymptotic at large λ n reprodu
ces the systematic large charge expansion\, recently derived in CFT.\nSimi
lar results can be derived in the U(1) model in 3-ε dimensions. I will br
iefly comment on the application of similar ideas in the calculation of ot
her observables\, such as three-point functions of charged operators. This
talk is based on https://arxiv.org/abs/1909.01269 and https://arxiv.org/a
bs/1911.08505.\n
LOCATION:https://researchseminars.org/talk/Kadanoff/4/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ki-Seok Kim (POSTECH)
DTSTART;VALUE=DATE-TIME:20200608T183000Z
DTEND;VALUE=DATE-TIME:20200608T193000Z
DTSTAMP;VALUE=DATE-TIME:20230208T075543Z
UID:Kadanoff/5
DESCRIPTION:Title: Emergent holographic dual effective field theory as a mean-field theory w
ith all-loop quantum corrections in the large N limit\nby Ki-Seok Kim
(POSTECH) as part of Kadanoff seminars\n\n\nAbstract\nHolographic duality
conjecture states that a D-dimensional quantum field theory can be duality
-mapped into a (D+1)-dimensional quantum gravity theory\, where the quantu
m gravity theory is a “hologram” of the quantum field theory. Although
this holographic duality conjecture serves as a novel non-perturbative th
eoretical framework for strongly coupled quantum field theories\, the dual
ity transformation has not been clarified until now. In this study we prop
ose a prescription for the holographic duality transformation based on Wil
sonian recursive renormalization group (RG) transformations. As a result\,
we manifest the RG flow of an effective field theory with the introductio
n of an emergent extra dimensional space\, where RG beta-functions to desc
ribe the evolution of coupling functions appear in the resulting effective
action explicitly through the extra dimensional space. This microscopic c
onstruction of the dual holographic mapping suggests that the origin of no
n-perturbative physics is in intertwined renormalization between dynamics
and geometry.\n
LOCATION:https://researchseminars.org/talk/Kadanoff/5/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Michael Aizenman (Princeton)
DTSTART;VALUE=DATE-TIME:20200615T183000Z
DTEND;VALUE=DATE-TIME:20200615T193000Z
DTSTAMP;VALUE=DATE-TIME:20230208T075543Z
UID:Kadanoff/6
DESCRIPTION:Title: Marginal triviality of the scaling limits of 4D critical Ising and $\\var
phi^4_4$ models\nby Michael Aizenman (Princeton) as part of Kadanoff s
eminars\n\n\nAbstract\nThe talk will outline the recent proof that the sca
ling limits of spin fluctuations in four-dimensional Ising-type models at
or near the critical point are Gaussian\, and of the similar statement for
the $\\varphi^4_4$ fields with a lattice ultraviolet cutoff\, in the limi
t of infinite volume and vanishing lattice spacing (derived jointly with
H. Duminil-Copin). The proofs are enabled by the models' random current r
epresentation\, in which the correlation functions' deviation from Wick's
law are expressed in terms of intersection probabilities of random current
s with prescribed sources. Examples will also be provided of insights f
acilitated by this representation for two and three dimensions.\n
LOCATION:https://researchseminars.org/talk/Kadanoff/6/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sri Raghu (Stanford)
DTSTART;VALUE=DATE-TIME:20200831T183000Z
DTEND;VALUE=DATE-TIME:20200831T193000Z
DTSTAMP;VALUE=DATE-TIME:20230208T075543Z
UID:Kadanoff/7
DESCRIPTION:Title: Dual perspective on quantum Hall to insulator transitions\nby Sri Rag
hu (Stanford) as part of Kadanoff seminars\n\n\nAbstract\nQuantum Hall to
insulator transitions (QHITs) are among the oldest and most studied exampl
es of quantum critical phenomena. In this talk I will discuss problems th
at still remain open in this subject\, and present a dual approach to QHIT
s based on composite fermion representations. I discuss the mean-field an
d fluctuational aspects of the dual theories\, and discuss how they provid
e a complementary understanding - and in many instances\, a conceptual ad
vantage - to current descriptions of QHITs based on the electron represent
ation.\n
LOCATION:https://researchseminars.org/talk/Kadanoff/7/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Shiraz Minwalla (TIFR Mumbai)
DTSTART;VALUE=DATE-TIME:20200908T150000Z
DTEND;VALUE=DATE-TIME:20200908T160000Z
DTSTAMP;VALUE=DATE-TIME:20230208T075543Z
UID:Kadanoff/8
DESCRIPTION:Title: Fermi seas from Bose condensates and a bosonic exclusion principle in mat
ter Chern Simons theories\nby Shiraz Minwalla (TIFR Mumbai) as part of
Kadanoff seminars\n\n\nAbstract\nI will study Chern Simons gauge theories
in three dimensions coupled to (bosonic or fermionic) matter in the funda
mental representation in the large N limit. I will first explain how previ
ously obtained results for the thermal free energy in these theories can b
e generalized to values of the chemical potential that are larger than qua
si particle mases. I will then use these results to find a simple explici
t formula for the occupation number for a bosonic quasiparticle state of a
ny given energy and charge as a function of the temperature and chemical p
otential. This formula is a generalization to finite 't Hooft coupling of
the famous result of Bose-Einstein statistics. It implies the following e
xclusion principle for large N Chern Simons coupled bosons: the total num
ber of bosons occupying any single state cannot exceed the Chern Simons le
vel. Specializing to zero temperature I will also construct the phase dia
grams of these theories as a function of chemical potential and the UV pa
rameters. The phase diagram includes a Bose condensed phase\, dual to the
Fermionic Fermi sea. The runaway instability of free theories at large che
mical potential is cured by the bosonic exclusion principle.\n
LOCATION:https://researchseminars.org/talk/Kadanoff/8/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Alex Maloney (McGill)
DTSTART;VALUE=DATE-TIME:20200914T183000Z
DTEND;VALUE=DATE-TIME:20200914T193000Z
DTSTAMP;VALUE=DATE-TIME:20230208T075543Z
UID:Kadanoff/9
DESCRIPTION:Title: Gravity from Averaging CFTs\nby Alex Maloney (McGill) as part of Kada
noff seminars\n\n\nAbstract\nI will explore the idea that certain theories
of gravity in Anti-de Sitter space are dual to an average over an ensembl
e of quantum theories\, rather than to a specific quantum theory. I will
describe an average over Narain’s family of two-dimensional conformal fi
eld theories which describe free bosons on a torus\, and compute the parti
tion function using the Siegel-Weil formula. The result takes the form of
a sum over geometries as one would expect in a theory of gravity. But th
e gravitational theory looks more like a Chern-Simons theory than like Ein
stein gravity.\n
LOCATION:https://researchseminars.org/talk/Kadanoff/9/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Hong Liu (MIT)
DTSTART;VALUE=DATE-TIME:20200921T183000Z
DTEND;VALUE=DATE-TIME:20200921T193000Z
DTSTAMP;VALUE=DATE-TIME:20230208T075543Z
UID:Kadanoff/10
DESCRIPTION:Title: Entanglement entropies of equilibrated pure states in quantum many-body
systems and replica wormholes\nby Hong Liu (MIT) as part of Kadanoff s
eminars\n\n\nAbstract\nWe develop a universal approximation for the Renyi
entropies of a pure state at late times in non-integrable systems\, which
macroscopically resembles an equilibrium density matrix. The resulting exp
ressions are fully determined by properties of the associated equilibrium
density matrix\, and are hence independent of the details of the initial s
tate\, while also being manifestly consistent with unitary time-evolution.
For equilibrated pure states in gravity systems\, such as those involving
black holes\, this approximation gives a prescription for calculating ent
anglement entropies using Euclidean path integrals which is consistent wit
h unitarity and hence can be used to address the information loss paradox
of Hawking. Applied to recent models of evaporating black holes and eterna
l black holes coupled to baths\, it provides a derivation of replica wormh
oles\, and elucidates their mathematical and physical origins. In particul
ar\, it shows that replica wormholes can arise in a system with a fixed Ha
miltonian\, without the need for ensemble averages.\n
LOCATION:https://researchseminars.org/talk/Kadanoff/10/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Mark Van Raamsdonk (University of British Columbia)
DTSTART;VALUE=DATE-TIME:20200928T183000Z
DTEND;VALUE=DATE-TIME:20200928T193000Z
DTSTAMP;VALUE=DATE-TIME:20230208T075543Z
UID:Kadanoff/11
DESCRIPTION:Title: Towards Microscopic Models of Big Bang Cosmology\nby Mark Van Raamsd
onk (University of British Columbia) as part of Kadanoff seminars\n\n\nAbs
tract\nIn this talk\, we review an approach to describing cosmological phy
sics using ordinary AdS/CFT\, where the cosmological physics is the effect
ive description of an end-of-the-world brane which cuts off the second asy
mptotic region of a two-sided black hole. The worldvolume geometry of the
brane is an FRW big-bang/big-crunch spacetime. In favorable circumstances\
, the brane acts as a Randall-Sundrum Planck brane so that gravity localiz
es. We describe a microscopic construction for such an end-of-the-world br
ane with localized gravity in AdS/CFT\, starting from N=4 SYM theory. We s
uggest specific microscopic states of N=4 SYM theory that may encode the p
hysics in a four-dimensional cosmological spacetime.\n
LOCATION:https://researchseminars.org/talk/Kadanoff/11/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Simon Caron-Huot (McGill)
DTSTART;VALUE=DATE-TIME:20201005T203000Z
DTEND;VALUE=DATE-TIME:20201005T213000Z
DTSTAMP;VALUE=DATE-TIME:20230208T075543Z
UID:Kadanoff/12
DESCRIPTION:Title: Dispersion relations for S-matrices and CFTs\nby Simon Caron-Huot (M
cGill) as part of Kadanoff seminars\n\n\nAbstract\nDispersion relations ar
e statements of causality. They give sum rules connecting low and high en
ergies. They are great. I will review some recently derived consequences
of causality and how they relate to dispersion relations. I will then dis
cuss a surprising equivalence between three seemingly distinct dispersion
relations in CFTs (in position space\, Mellin space\, and analytic functio
nals)\, and a lesson for flat-space gravity.\n
LOCATION:https://researchseminars.org/talk/Kadanoff/12/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Julian Sonner (University of Geneva)
DTSTART;VALUE=DATE-TIME:20201012T183000Z
DTEND;VALUE=DATE-TIME:20201012T193000Z
DTSTAMP;VALUE=DATE-TIME:20230208T075543Z
UID:Kadanoff/13
DESCRIPTION:Title: Causal symmetry breaking: late time physics of holographic quantum chaos
\nby Julian Sonner (University of Geneva) as part of Kadanoff seminars
\n\n\nAbstract\nQuantum chaotic systems are often defined via the assertio
n that their spectral statistics coincides with\, or is well approximated
by\, random matrix theory. In this talk I will explain how the universal c
ontent of random matrix theory emerges as the consequence of a simple symm
etry-breaking principle and its associated Goldstone modes. Within AdS/CFT
this gives a universal framework to express correlations between ``differ
ent universes’’\, including for individual theories rather than ensemb
les. I will Illustrate the bulk picture of this EFT using the example mini
mal string theory. I will end by discussing the construction of the EFT of
quantum chaos also in higher dimensional field theories\, as applicable f
or example for higher-dimensional AdS/CFT dual pairs.\n
LOCATION:https://researchseminars.org/talk/Kadanoff/13/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ryan Thorngren (Harvard CMSA)
DTSTART;VALUE=DATE-TIME:20201019T183000Z
DTEND;VALUE=DATE-TIME:20201019T193000Z
DTSTAMP;VALUE=DATE-TIME:20230208T075543Z
UID:Kadanoff/14
DESCRIPTION:Title: 't Hooft Anomalies of Fermi Liquids and Luttinger's Theorem\nby Ryan
Thorngren (Harvard CMSA) as part of Kadanoff seminars\n\n\nAbstract\nLatt
ice systems with translation symmetry and U(1) charge conservation have a
filling fraction\, defined as the charge per unit cell. In this talk I wil
l explain how the filling fraction is captured by anomalous emergent symme
tries in the continuum limit of such systems. This anomaly matching is a g
eneralization of Luttinger's theorem for Fermi liquids\, which says that t
he filling fraction equals the volume enclosed by the Fermi surface. Lutti
nger's theorem is obtained by analyzing an anomalous loop-group symmetry o
f the Fermi liquid\, which generalizes the chiral anomaly of a Luttinger l
iquid in 1+1d. I will argue more generally that systems at irrational fill
ing cannot have continuum limits with compact symmetry groups.\n
LOCATION:https://researchseminars.org/talk/Kadanoff/14/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ehud Altman (Berkeley)
DTSTART;VALUE=DATE-TIME:20201109T193000Z
DTEND;VALUE=DATE-TIME:20201109T203000Z
DTSTAMP;VALUE=DATE-TIME:20230208T075543Z
UID:Kadanoff/15
DESCRIPTION:Title: Symmetry and information flow in quantum circuits with measurements\
nby Ehud Altman (Berkeley) as part of Kadanoff seminars\n\n\nAbstract\nI w
ill discuss novel quantum phases and phase transitions that emerge in the
dynamics of quantum circuits and represent distinct modes of information f
low. I consider a system in which the time evolution by random unitary gat
es is occasionally interrupted by local measurements. It was previously fo
und that such evolution leads to a phase transition in the entanglement of
the wavefunction: at steady state it is characterized by volume law entan
glement for small measurement rate\, while it is an area law above a thres
hold rate. I will investigate this phase transition by mapping the quantum
dynamics into classical statistical mechanics models in equilibrium. Furt
hermore\, we show that more phases are possible if we impose symmetries on
the dynamics. To identify the phases\, we develop a mapping between the i
nformation dynamics in a broad class of circuits to the ground states of e
ffective spin Hamiltonians\, which possess a higher symmetry than the orig
inal circuit. The different ground state phases admitted by the higher eff
ective symmetry correspond to distinct patterns of information flow and sc
rambling in the circuit dynamics. We illustrate these ideas with two examp
les: (i) a quantum circuit with Z_2 symmetry resulting in non-abelian D_4
symmetry in an effective Hamiltonian and (ii) a quadratic fermionic circui
t leading to U(1) symmetry. The latter exhibits Kosterlitz–Thouless tran
sition in 1D between a critical phase with log(L) entanglement and "trivia
l" area law phases. Our work is a first step toward the classification of
information flow in generic quantum circuits.\n
LOCATION:https://researchseminars.org/talk/Kadanoff/15/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Israel Klich (University of Virginia)
DTSTART;VALUE=DATE-TIME:20201026T183000Z
DTEND;VALUE=DATE-TIME:20201026T193000Z
DTSTAMP;VALUE=DATE-TIME:20230208T075543Z
UID:Kadanoff/16
DESCRIPTION:by Israel Klich (University of Virginia) as part of Kadanoff s
eminars\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/Kadanoff/16/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Alexander Seidel (Washington University in St. Louis)
DTSTART;VALUE=DATE-TIME:20201214T193000Z
DTEND;VALUE=DATE-TIME:20201214T203000Z
DTSTAMP;VALUE=DATE-TIME:20230208T075543Z
UID:Kadanoff/17
DESCRIPTION:Title: Entangled Pauli Principles\nby Alexander Seidel (Washington Universi
ty in St. Louis) as part of Kadanoff seminars\n\n\nAbstract\nA major chall
enge in the study of strongly correlated electron systems is to establish
a firm link between microscopic models and effective field theory. Quite o
ften\, this step involves a leap of faith\, and/or extensive numerical stu
dies. For fractional quantum Hall model wave functions\, there exists —
in some cases — a scheme to infer the long distance physics of a state t
hat is both compelling and simple\, and leaves very little room for ambigu
ity. This scheme involves a local parent Hamiltonian for the state\, which
unambiguously defines a ``zero mode space’’ of elementary excitations
\, and what’s known as a ``generalized Pauli principle’’. The latte
r efficiently organizes the zero mode space through one-dimensional patter
ns satisfying local rules and effectively functions as the ``DNA’’ of
the topological phase:\nWhere this works\, universal properties of the sta
te emerge from counting exercises in terms of these patterns\, which effic
iently and unambiguously encode the edge conformal field theory and relate
d topological data. This includes a natural scheme to infer braiding stati
stics directly\, for both Abelian and non-Abelian states. The strong link
between microscopics and effective theory brought about by the existence o
f a particular type of parent Hamiltonian\, one which enforces a Pauli-lik
e in its zero modes\, is thus far limited to a subset of the myriad phases
possible in the fractional quantum Hall regime. I will report on recent p
rogress on extending this paradigm into new terrain where it previously di
d not\, or did not fully apply\, including most composite fermion states a
nd their ``parton’’ generalizations\, leading to ``entangled’’ Pau
li-like principles. I will argue that these examples suggest the beginnin
gs of a new ``Hamiltonian building’’ framework that capitalizes on the
matrix product form of fractional quantum Hall trial states\, rather than
their analytic first quantized form.\n
LOCATION:https://researchseminars.org/talk/Kadanoff/17/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Tomaž Prosen (University of Ljubljana)
DTSTART;VALUE=DATE-TIME:20201102T193000Z
DTEND;VALUE=DATE-TIME:20201102T203000Z
DTSTAMP;VALUE=DATE-TIME:20230208T075543Z
UID:Kadanoff/18
DESCRIPTION:Title: Exactly solved models of many-body quantum chaos\nby Tomaž Prosen (
University of Ljubljana) as part of Kadanoff seminars\n\n\nAbstract\nOne s
hould be amazed with the unreasonable effectiveness of random matrix theor
y to describe spectral fluctuations in simple non-integrable many-body sys
tems\, say one dimensional spin 1/2 chains with local interactions. I will
discuss several models of Floquet (periodically driven) quantum spin chai
ns\, where the random matrix result for the spectral form factor can be de
rived or even rigorously proven. Several other nontrivial exactly solvable
features of the presented models\, such as dynamical correlations or enta
nglement dynamics\, will be discussed.\n
LOCATION:https://researchseminars.org/talk/Kadanoff/18/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Leo Radzihovsky (University of Colorado Boulder)
DTSTART;VALUE=DATE-TIME:20201207T193000Z
DTEND;VALUE=DATE-TIME:20201207T203000Z
DTSTAMP;VALUE=DATE-TIME:20230208T075543Z
UID:Kadanoff/19
DESCRIPTION:Title: Quantum smectic gauge theory\nby Leo Radzihovsky (University of Colo
rado Boulder) as part of Kadanoff seminars\n\n\nAbstract\nI will discuss a
gauge theory formulation of a two-dimensional quantum smectic and its rel
atives\, motivated by their realizations in correlated quantum matter. The
description gives a unified treatment of phonons and topological defects\
, respectively encoded in a pair of coupled gauge fields and corresponding
charges. The charges exhibit subdimensional constrained quantum dynamics
and anomalously slow highly anisotropic diffusion of disclinations inside
a smectic. This approach gives a transparent description of a multi-stage
quantum melting transition of a two-dimensional commensurate crystal (thro
ugh an incommensurate crystal -- a supersolid) into a quantum smectic\, th
at subsequently melts into a quantum nematic and isotropic superfluids\, a
ll in terms of a sequence of Higgs transitions.\n
LOCATION:https://researchseminars.org/talk/Kadanoff/19/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Venkatesa Chandrasekaran (Berkeley)
DTSTART;VALUE=DATE-TIME:20201116T193000Z
DTEND;VALUE=DATE-TIME:20201116T203000Z
DTSTAMP;VALUE=DATE-TIME:20230208T075543Z
UID:Kadanoff/20
DESCRIPTION:Title: Gravity dual of Connes cocycle flow\nby Venkatesa Chandrasekaran (Be
rkeley) as part of Kadanoff seminars\n\n\nAbstract\nGravity dual of Connes
cocycle flow\, Venkatesa Chandrasekaran\, Berkley\nModular flow offers a
wealth of insights into both quantum field theory and holography. Its conn
ection to gravity has implications for understanding bulk reconstruction a
nd boundary entanglement. In this talk\, I will further explore this conne
ction by studying a regularized version of one-sided modular flow: the Con
nes Cocycle (CC) flow. I will define the “kink transform” as a one-sid
ed boost of bulk initial data about the Ryu-Takayanagi surface of a bounda
ry cut. For a flat cut\, I will demonstrate that the resulting Wheeler-DeW
itt patch is the bulk dual to the boundary state obtained by CC flow acros
s the cut. I will do so by verifying that the kink transform is consistent
with known properties of operator expectation values and subregion entrop
ies under CC flow. Moreover\, I will show that CC flow generates a stress
tensor shock at the cut\, controlled by a shape derivative of the entropy.
I will demonstrate that the kink transform reproduces this shock holograp
hically through a gravitational shock. I will also discuss the relationshi
p to one-sided modular flow and JLMS.\n
LOCATION:https://researchseminars.org/talk/Kadanoff/20/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Brian Swingle (University of Maryland)
DTSTART;VALUE=DATE-TIME:20201130T193000Z
DTEND;VALUE=DATE-TIME:20201130T203000Z
DTSTAMP;VALUE=DATE-TIME:20230208T075543Z
UID:Kadanoff/21
DESCRIPTION:Title: Hydrodynamics and the Spectral Form Factor\nby Brian Swingle (Univer
sity of Maryland) as part of Kadanoff seminars\n\n\nAbstract\nHydrodynamic
s and the Spectral Form Factor\, Brian Swingle\, University of Maryland\nE
nsembles of quantum chaotic systems are expected to exhibit random matrix
universality in their energy spectrum. The presence of this universality c
an be diagnosed by looking for a linear in time 'ramp' in the spectral for
m factor\, but for realistic systems this feature is typically only visibl
e after a sufficiently long time. I will discuss several developments in o
ur understanding of this intermediate time regime in the spectral form fac
tor. First\, I will describe a hybrid system in which the single particle
levels are chaotic while the many-body levels are those of non-interacting
particles. In this case\, the linear ramp is replaced by an exponential r
amp. Interacting deformations of the system can then lead to full many-bod
y quantum chaos\, but the approach to a linear ramp can be slow due to the
presence of nearly conserved modes. Motivated by this problem\, I will pr
esent a theory of the spectral form factor in systems with slow modes and
will apply the results to a variety of hydrodynamic systems. Joint work wi
th Mike Winer and Shaokai Jian.\n
LOCATION:https://researchseminars.org/talk/Kadanoff/21/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Gabriel Wong (Fudan University)
DTSTART;VALUE=DATE-TIME:20201123T160000Z
DTEND;VALUE=DATE-TIME:20201123T170000Z
DTSTAMP;VALUE=DATE-TIME:20230208T075543Z
UID:Kadanoff/22
DESCRIPTION:Title: Entanglement entropy and edge modes in topological string theory\nby
Gabriel Wong (Fudan University) as part of Kadanoff seminars\n\n\nAbstrac
t\nThe Ryu Takayanagi formula identifies the area of boundary anchored ext
remal surfaces in AdS with the entanglement entropy of the boundary CFT. H
owever the bulk microstate interpretation of the extremal area remains mys
terious. Progress along this direction requires understanding how to defi
ne entanglement entropy in the bulk closed string theory. As a toy model
for AdS/CFT\, we study the entanglement entropy of closed strings in the
topological A model in the context of Gopakumar Vafa duality. We give a
self consistent factorization of the closed string Hilbert space which lea
ds to string edge modes transforming under a q-deformed surface symmetry
group. Compatibility with this symmetry requires a q-deformed definiti
on of entanglement entropy. Using the topological vertex formalism\, we
define the Hartle Hawking state for the resolved conifold and compute its
q-deformed entropy directly from the closed string reduced density matrix
. We find a match with a target space replica calculation using the propo
sal of Susskind and Uglum. We then apply the Gopakumar Vafa duality to
reproduce the closed string entropy from Chern Simons theory using the un
-deformed definition of entanglement entropy. Finally we relate non loc
al aspects of our factorization map to analogous phenomenon recently found
in JT gravity..\n
LOCATION:https://researchseminars.org/talk/Kadanoff/22/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Matthias Gaberdiel (ETH Zurich)
DTSTART;VALUE=DATE-TIME:20210111T193000Z
DTEND;VALUE=DATE-TIME:20210111T203000Z
DTSTAMP;VALUE=DATE-TIME:20230208T075543Z
UID:Kadanoff/23
DESCRIPTION:Title: An exact AdS/CFT duality\nby Matthias Gaberdiel (ETH Zurich) as part
of Kadanoff seminars\n\n\nAbstract\nString theory on AdS3 x S3 x T4 with
one unit of NS-NS flux is argued to be exactly dual to the symmetric orbif
old of T4 in the large N limit. The string theory background can be descri
bed in terms of a solvable world-sheet theory. This allows one to compute
the complete single-string spacetime spectrum and thereby demonstrate that
it agrees with that of the symmetric orbifold of T4. Furthermore\, the st
ructure of the symmetric orbifold correlators can be reproduced from the w
orld-sheet perspective. I will finally also explain how the world-sheet th
eory can be reconstructed from the symmetric orbifold theory in a Gross-Me
nde like limit.\n
LOCATION:https://researchseminars.org/talk/Kadanoff/23/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Mukund Rangamani (UC Davis)
DTSTART;VALUE=DATE-TIME:20210125T193000Z
DTEND;VALUE=DATE-TIME:20210125T203000Z
DTSTAMP;VALUE=DATE-TIME:20230208T075543Z
UID:Kadanoff/25
DESCRIPTION:Title: Real-time gravitational replicas\nby Mukund Rangamani (UC Davis) as
part of Kadanoff seminars\n\n\nAbstract\nI will discuss real-time path int
egrals in gravitational theories. As applications we will describe the gen
eral structure of replica wormhole saddles and exemplify them with some lo
w dimensional examples. Time permitting\, I will also mention\, some aspe
cts of effective dynamics of open quantum systems with long-term memory.\n
LOCATION:https://researchseminars.org/talk/Kadanoff/25/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Aaron Hui (Cornell)
DTSTART;VALUE=DATE-TIME:20210201T193000Z
DTEND;VALUE=DATE-TIME:20210201T203000Z
DTSTAMP;VALUE=DATE-TIME:20230208T075543Z
UID:Kadanoff/26
DESCRIPTION:Title: Beyond Ohm’s law—Bernoulli effect and streaming in electron hydrodyn
amics\nby Aaron Hui (Cornell) as part of Kadanoff seminars\n\nAbstract
: TBA\n
LOCATION:https://researchseminars.org/talk/Kadanoff/26/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sid Parameswaran (Oxford)
DTSTART;VALUE=DATE-TIME:20210301T193000Z
DTEND;VALUE=DATE-TIME:20210301T203000Z
DTSTAMP;VALUE=DATE-TIME:20230208T075543Z
UID:Kadanoff/27
DESCRIPTION:by Sid Parameswaran (Oxford) as part of Kadanoff seminars\n\nA
bstract: TBA\n
LOCATION:https://researchseminars.org/talk/Kadanoff/27/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Yunfeng Jiang (CERN)
DTSTART;VALUE=DATE-TIME:20210208T193000Z
DTEND;VALUE=DATE-TIME:20210208T203000Z
DTSTAMP;VALUE=DATE-TIME:20230208T075543Z
UID:Kadanoff/28
DESCRIPTION:Title: Dynamical hard rods and TTbar deformation\nby Yunfeng Jiang (CERN) a
s part of Kadanoff seminars\n\n\nAbstract\nIn this talk\, I will show that
TTbar and a family of more general solvable bilinear deformations have th
e effect of deforming point particles into hard rods with finite size. Thi
s can be seen most easily for non-relativistic systems where the number of
excitations is conserved. I will discuss this picture from two different
perspectives. In the first part\, I will discuss TTbar deformation of a co
ncrete model\, which is the 1d Bose gas. In the second part\, I will provi
de a 2d gravity interpretation for the TTbar deformation of generic non-re
lativistic QFTs in the framework of Newton-Cartan geometry. Finally\, I wi
ll discuss the physical implications of the hard rod picture.\n
LOCATION:https://researchseminars.org/talk/Kadanoff/28/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Cheng Chin (U Chicago)
DTSTART;VALUE=DATE-TIME:20210215T193000Z
DTEND;VALUE=DATE-TIME:20210215T203000Z
DTSTAMP;VALUE=DATE-TIME:20230208T075543Z
UID:Kadanoff/29
DESCRIPTION:Title: Super-resolution microscopy of cold atoms in optical lattices\nby Ch
eng Chin (U Chicago) as part of Kadanoff seminars\n\n\nAbstract\nSuper-res
olution microscopy has revolutionized the fields of chemistry and biology
by resolving features at the molecular level. With cold atoms\, such a sch
eme can be applied to the length scale of atomic wavefunction and to perfo
rm quantum control. Here we report super-resolution imaging based on nonli
near response of optical pumping. With this technique the atomic density d
istribution can be imaged with a half-width-at-half-maximum resolution of
16(2) nm and a localization precision below 0.5 nm. The short optical pump
ing pulse of 1.4 us enables us to resolve fast atomic motion in the lattic
e. A surprising application of our scheme is the emergence of moiré patte
rns on the atomic cloud\, which we show to be immensely magnified images o
f the atomic cloud.\n
LOCATION:https://researchseminars.org/talk/Kadanoff/29/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Marcel Franz (University of British Columbia)
DTSTART;VALUE=DATE-TIME:20210222T193000Z
DTEND;VALUE=DATE-TIME:20210222T203000Z
DTSTAMP;VALUE=DATE-TIME:20230208T075543Z
UID:Kadanoff/30
DESCRIPTION:Title: High-temperature topological superconductivity in twisted double layer c
opper oxide\nby Marcel Franz (University of British Columbia) as part
of Kadanoff seminars\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/Kadanoff/30/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Nathan Benjamin (Princeton)
DTSTART;VALUE=DATE-TIME:20210308T193000Z
DTEND;VALUE=DATE-TIME:20210308T203000Z
DTSTAMP;VALUE=DATE-TIME:20230208T075543Z
UID:Kadanoff/31
DESCRIPTION:Title: Narain to Narnia\nby Nathan Benjamin (Princeton) as part of Kadanoff
seminars\n\n\nAbstract\nWe generalize the recent holographic corresponden
ce between an ensemble average of free bosons in two dimensions\, and a Ch
ern-Simons-like theory of gravity in three dimensions\, by Afkhami-Jeddi e
t al and Maloney and Witten. We find that the correspondence also works fo
r toroidal orbifolds\, but we run into difficulties generalizing to K3 and
Calabi-Yau sigma models. For the case of toroidal orbifolds\, we extend t
he holographic correspondence to averages of correlation functions of twis
t operators by using properties of rational tangles in three-dimensional b
alls and their covering spaces. Based on work to appear with C. Keller\, H
. Ooguri\, and I. Zadeh.\n
LOCATION:https://researchseminars.org/talk/Kadanoff/31/
END:VEVENT
BEGIN:VEVENT
SUMMARY:William Witczak-Krempa (University of Montreal)
DTSTART;VALUE=DATE-TIME:20210322T183000Z
DTEND;VALUE=DATE-TIME:20210322T193000Z
DTSTAMP;VALUE=DATE-TIME:20230208T075543Z
UID:Kadanoff/32
DESCRIPTION:Title: Cornering the universal shape of fluctuations and entanglement\nby W
illiam Witczak-Krempa (University of Montreal) as part of Kadanoff seminar
s\n\n\nAbstract\nUnderstanding the fluctuations of observables is one of t
he main goals in physics. We investigate such fluctuations when a subregio
n of the full system can be observed\, focusing on geometries with corners
. We report that the dependence on the opening angle is super-universal: u
p to a numerical prefactor\, this function does not depend on anything\, p
rovided the system under study is uniform\, isotropic\, and correlations d
o not decay too slowly. The prefactor contains important physical informat
ion: we show in particular that it gives access to the long-wavelength lim
it of the structure factor. We illustrate our findings with several exampl
es: classical fluids\, fractional quantum Hall (FQH) states\, scale invari
ant quantum critical theories\, and metals. Finally\, we discuss connectio
ns with the entanglement entropy\, including new results for Laughlin FQH
states. Ref: arXiv:2102.06223\n
LOCATION:https://researchseminars.org/talk/Kadanoff/32/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Andrea Guerrieri (ICTP-SAIFR\, Sao Paulo)
DTSTART;VALUE=DATE-TIME:20210329T183000Z
DTEND;VALUE=DATE-TIME:20210329T193000Z
DTSTAMP;VALUE=DATE-TIME:20230208T075543Z
UID:Kadanoff/33
DESCRIPTION:by Andrea Guerrieri (ICTP-SAIFR\, Sao Paulo) as part of Kadano
ff seminars\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/Kadanoff/33/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Herman Verlinde (Princeton)
DTSTART;VALUE=DATE-TIME:20210405T183000Z
DTEND;VALUE=DATE-TIME:20210405T193000Z
DTSTAMP;VALUE=DATE-TIME:20230208T075543Z
UID:Kadanoff/34
DESCRIPTION:Title: Towards a string dual of SYK\nby Herman Verlinde (Princeton) as part
of Kadanoff seminars\n\n\nAbstract\nIn this talk I'll present a proposal
for a string realization of the SYK model as the world-line theory of Q FZ
ZT branes in (p\,1) minimal string theory. Starting from the two-matrix mo
del description of the minimal string\, I show that the FZZT brane partiti
on function takes the form of a matrix version of the SYK model. I'll then
describe how time emerges upon taking the continuum limit. I'll briefly c
omment on possible implications of our result for the string dual interpre
tation of the SYK model and for the role of ensemble averaging in low dime
nsional holography.\n
LOCATION:https://researchseminars.org/talk/Kadanoff/34/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ilya Esterlis (Harvard)
DTSTART;VALUE=DATE-TIME:20210412T183000Z
DTEND;VALUE=DATE-TIME:20210412T193000Z
DTSTAMP;VALUE=DATE-TIME:20230208T075543Z
UID:Kadanoff/35
DESCRIPTION:Title: Large N theory of critical Fermi surfaces\nby Ilya Esterlis (Harvard
) as part of Kadanoff seminars\n\n\nAbstract\nI will discuss recent work o
n a large-N theory of critical Fermi surfaces in two dimensions. The theor
y applies directly to the onset of Ising order in a Fermi liquid\, and is
easily generalized to other forms of order. By employing random couplings
in flavor-space while retaining spatial translation invariance\, we find t
he large-N saddle point equations are the same as those appearing in other
contexts\; e.g.\, Eliashberg-like theories\, and our approach therefore p
rovides a systematic framework for assessing and going beyond such theorie
s. I will also discuss the the large-N phase diagram of the system away fr
om criticality\, and show that the ordered side is characterized by a regi
me of unusually strong thermal fluctuations. Time permitting\, I will also
review the behavior of various fermion bilinear operators\, which can be
used to diagnose the instabilities of the critical Fermi surface.\n
LOCATION:https://researchseminars.org/talk/Kadanoff/35/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Hank Lamm (Fermilab)
DTSTART;VALUE=DATE-TIME:20210419T183000Z
DTEND;VALUE=DATE-TIME:20210419T193000Z
DTSTAMP;VALUE=DATE-TIME:20230208T075543Z
UID:Kadanoff/36
DESCRIPTION:Title: Quantum Simulations for High Energy Physics\nby Hank Lamm (Fermilab)
as part of Kadanoff seminars\n\n\nAbstract\nThe advent of quantum computa
tion presents the opportunity to solve questions in high energy physics wh
ich are inaccessible to classical computation such as real-time evolution
and the equation of state at finite density. In order to take advantage of
this new resource\, a number of theoretical and computational hurdles wil
l need to be addressed. In this talk\, I will discuss the state of the ar
t research being performed in HEP and outstanding questions that require o
ur attention going forward\, focusing on digitization of lattice gauge the
ories and extracting physical results that demonstrate practical quantum a
dvantage.\n
LOCATION:https://researchseminars.org/talk/Kadanoff/36/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Anatoly Dymarsky (University of Kentucky)
DTSTART;VALUE=DATE-TIME:20210426T183000Z
DTEND;VALUE=DATE-TIME:20210426T193000Z
DTSTAMP;VALUE=DATE-TIME:20230208T075543Z
UID:Kadanoff/37
DESCRIPTION:Title: Quantum codes\, conformal field theory\, and holography\nby Anatoly
Dymarsky (University of Kentucky) as part of Kadanoff seminars\n\n\nAbstra
ct\nClassical error correcting codes are related to special lattices\, whi
ch give rise to chiral CFTs. Recently this story was generalized to non-ch
iral theories. In this case quantum codes give rise to Narain lattices and
a special family of Narain theories which we dub code CFTs. Some of these
code theories maximize the spectral gap\, making connection with the conf
ormal bootstrap program. From the holographic point of view\, code CFTs fo
rm an ensemble which provides a simplified model for the recently introduc
ed duality between ensembles of boundary theories and quantum gravity in t
he bulk. In this talk I will first describe the mapping between quantum co
des and Narain theories\, and then discuss examples of optimal CFTs which
maximize the spectral gap. In the second part of the talk I will discuss t
he ensemble of code theories and several lessons they presumably teach us
about the ensemble of all Narain theories and its holographic description.
\n
LOCATION:https://researchseminars.org/talk/Kadanoff/37/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Shu-Heng Shao (IAS)
DTSTART;VALUE=DATE-TIME:20210503T183000Z
DTEND;VALUE=DATE-TIME:20210503T193000Z
DTSTAMP;VALUE=DATE-TIME:20230208T075543Z
UID:Kadanoff/38
DESCRIPTION:Title: Obstructions to Gapped Boundaries from Three-Manifold Invariants\nby
Shu-Heng Shao (IAS) as part of Kadanoff seminars\n\n\nAbstract\nWe derive
new obstructions to a 2+1d bosonic TQFT (such as the Chern-Simons theory)
admitting a gapped boundary. Each such obstruction is labeled by a closed
three-manifold\, and it arises as the phase of the Reshetikhin–Turaev i
nvariant. Using these new obstructions and earlier results on this subject
\, we prove the following. \n(1) An abelian bosonic TQFT admits a gapped b
oundary iff a finite list of certain "higher central charges" vanish. \n(2
) No power of the Fibonacci anyon (a.k.a. the (G2)_1 Chern-Simons theory)
admits a gapped boundary. \nThis talk will be based on work in progress wi
th J. Kaidi\, Z. Komargodski\, K. Ohmori\, S. Seifnashri.\n
LOCATION:https://researchseminars.org/talk/Kadanoff/38/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Mark Mezei (Stony Brook)
DTSTART;VALUE=DATE-TIME:20210510T183000Z
DTEND;VALUE=DATE-TIME:20210510T193000Z
DTSTAMP;VALUE=DATE-TIME:20230208T075543Z
UID:Kadanoff/39
DESCRIPTION:Title: Effective field theories for quantum chaos\nby Mark Mezei (Stony Bro
ok) as part of Kadanoff seminars\n\n\nAbstract\nQuantum chaotic dynamics i
s associated to diverse physical phenomena and signatures. In this talk\,
we describe progress in building effective theories for three of these: th
e growth of operators\, the pole skipping phenomenon\, and thermalization
through the lens of entanglement entropy. We uncover their interplay by sh
owing that the butterfly velocity plays an important role in all three man
ifestations of chaos. The discussion is informed by results from AdS/CFT a
nd from models of SYK type.\n
LOCATION:https://researchseminars.org/talk/Kadanoff/39/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ethan Dyer and Guy Gur-Ari (Google)
DTSTART;VALUE=DATE-TIME:20210517T193000Z
DTEND;VALUE=DATE-TIME:20210517T203000Z
DTSTAMP;VALUE=DATE-TIME:20230208T075543Z
UID:Kadanoff/40
DESCRIPTION:Title: The role of scale in deep neural networks\nby Ethan Dyer and Guy Gur
-Ari (Google) as part of Kadanoff seminars\n\n\nAbstract\nModern deep lear
ning has made remarkable progress across a wide variety of domains. A key
ingredient to this success has been increasingly big models trained on inc
reasingly large datasets. I will discuss theoretical and empirical work at
tempting to understand how performance improves with scale and distinguish
ing problems which can be solved by scale alone from those where new ideas
are needed.\n
LOCATION:https://researchseminars.org/talk/Kadanoff/40/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Zhenbin Yang (Stanford)
DTSTART;VALUE=DATE-TIME:20210524T183000Z
DTEND;VALUE=DATE-TIME:20210524T193000Z
DTSTAMP;VALUE=DATE-TIME:20230208T075543Z
UID:Kadanoff/41
DESCRIPTION:Title: Wormholes and Unitarity of Black Hole Evolution Process\nby Zhenbin
Yang (Stanford) as part of Kadanoff seminars\n\n\nAbstract\nI will discuss
a working progress on understanding small effects associated to unitarity
of black hole evolution process using wormhole geometries. Based on colla
boration with Douglas Stanford and Shunyu Yao.\n
LOCATION:https://researchseminars.org/talk/Kadanoff/41/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sandipan Kundu (Johns Hopkins University)
DTSTART;VALUE=DATE-TIME:20210531T183000Z
DTEND;VALUE=DATE-TIME:20210531T193000Z
DTSTAMP;VALUE=DATE-TIME:20230208T075543Z
UID:Kadanoff/42
DESCRIPTION:Title: Swampland Conditions from CFT\nby Sandipan Kundu (Johns Hopkins Univ
ersity) as part of Kadanoff seminars\n\n\nAbstract\nThere are effective fi
eld theories that cannot be embedded in any UV complete theory. I will dis
cuss precise bounds on the IR coupling constants of higher derivative inte
ractions from UV consistency. In particular\, I will explain how to system
atically derive constraints on higher derivative coupling of scalar effect
ive field theories\, with and without dynamical gravity\, in anti-de Sitte
r spacetime with large radius by only requiring that the dual CFT obeys th
e well-established conformal bootstrap axioms. Hence\, this set-up avoids
many of the loopholes of flat space S-matrix based arguments that lead to
similar bounds. As an application\, I will use this framework to impose co
nstraints on the low energy effective action associated with unitary RG fl
ows in 4d with a broken global U(1) symmetry in the UV.\n
LOCATION:https://researchseminars.org/talk/Kadanoff/42/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Matthew Lapa (University of Chicago)
DTSTART;VALUE=DATE-TIME:20210607T183000Z
DTEND;VALUE=DATE-TIME:20210607T193000Z
DTSTAMP;VALUE=DATE-TIME:20230208T075543Z
UID:Kadanoff/43
DESCRIPTION:Title: Momentum occupation number bounds for interacting fermions\nby Matth
ew Lapa (University of Chicago) as part of Kadanoff seminars\n\n\nAbstract
\nI will present rigorous bounds on the momentum occupation numbers in tra
nslation invariant free fermion models perturbed by Hubbard interactions a
nd a non-uniform potential. In particular\, at finite temperature I will p
resent a bound on the deviation of the momentum occupation numbers from th
e non-interacting Fermi-Dirac distribution. Among other things\, this boun
d shows that the momentum distribution is very close to that of a low-temp
erature free Fermi gas in the regime where interaction strength << kT << F
ermi energy. This work is motivated by Luttinger’s theorem and related r
ecent work on the momentum space picture of interacting fermions. While th
ose results are interesting\, their derivations rely on various assumption
s\, and such strong results are unlikely to hold for generic models of int
eracting fermions. In contrast to this situation\, the results that I will
present hold for concrete models and can serve as a useful starting point
for understanding the physics of interacting fermions.\n
LOCATION:https://researchseminars.org/talk/Kadanoff/43/
END:VEVENT
END:VCALENDAR