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VERSION:2.0
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BEGIN:VEVENT
SUMMARY:Tensor networks for critical systems
DTSTART;VALUE=DATE-TIME:20201116T140000Z
DTEND;VALUE=DATE-TIME:20201116T145000Z
DTSTAMP;VALUE=DATE-TIME:20210612T202506Z
UID:indico-contribution-2-2@events.perimeterinstitute.ca
DESCRIPTION:Speakers: Frank Verstraete (University of Vienna & University
of Ghent)\nIn this talk I will give an overview of tensor network approach
es to critical systems. I will discuss entanglement scaling laws\, show ho
w PEPS can simulate systems with Fermi surfaces\, and present some results
for simulating systems in the continuum.\n\nhttps://events.perimeterinsti
tute.ca/event/2/contributions/2/
LOCATION:Perimeter Institute
URL:https://events.perimeterinstitute.ca/event/2/contributions/2/
END:VEVENT
BEGIN:VEVENT
SUMMARY:An overview of Wavelets and MERA
DTSTART;VALUE=DATE-TIME:20201120T180000Z
DTEND;VALUE=DATE-TIME:20201120T185000Z
DTSTAMP;VALUE=DATE-TIME:20210612T202506Z
UID:indico-contribution-2-19@events.perimeterinstitute.ca
DESCRIPTION:Speakers: Glen Evenbly (University of Sherbrooke)\nThe use of
wavelet-based constructions has led to significant progress in the analyti
c understanding of holographic tensor networks\, such as the multi-scale e
ntanglement renormalization ansatz (MERA). In this talk I will give an ove
rview of the (past and more recently established) connections between wave
lets and MERA\, and the discuss the important results that have followed.
I will also discuss work currently underway that exploits the wavelet-MERA
connection in order to produce new families of wavelets that are optimal
for certain tasks\, such as image compression.\n\nhttps://events.perimeter
institute.ca/event/2/contributions/19/
LOCATION:Perimeter Institute
URL:https://events.perimeterinstitute.ca/event/2/contributions/19/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Unconstrained tree tensor simulations for high-dimensional quantum
many-body simulations
DTSTART;VALUE=DATE-TIME:20201120T140000Z
DTEND;VALUE=DATE-TIME:20201120T145000Z
DTSTAMP;VALUE=DATE-TIME:20210612T202506Z
UID:indico-contribution-2-18@events.perimeterinstitute.ca
DESCRIPTION:Speakers: Simone Montangero (Padova University)\nWe present so
me recent results on the development of efficient unconstrained tree tenso
r networks algorithms and their application to high-dimensional many-body
quantum systems. In particular\, we present our results on topological two
-dimensional systems\, two-dimensional Rydberg atom systems\, and two- an
d three-dimensional lattice gauge theories in presence of fermonic matter.
Finally\, we present their application to the study of open many-body qua
ntum systems and in particular to the computation of the entanglement of
formation in critical many-body quantum systems\, resulting in the general
ization of the Calabrese-Cardy formula to open systems.\n\nhttps://events
.perimeterinstitute.ca/event/2/contributions/18/
LOCATION:Perimeter Institute
URL:https://events.perimeterinstitute.ca/event/2/contributions/18/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Dimensional Expressivity Analysis for Quantum Circuits
DTSTART;VALUE=DATE-TIME:20201118T180000Z
DTEND;VALUE=DATE-TIME:20201118T185000Z
DTSTAMP;VALUE=DATE-TIME:20210612T202506Z
UID:indico-contribution-2-10@events.perimeterinstitute.ca
DESCRIPTION:Speakers: Tobias Hartung (Deutsches Elektronen-Synchrotron)\n"
Besides tensor networks\, quantum computations (QC) as well use a Hamilton
ian formulation to solve physical problems. Although QC are presently very
limited\, since only small number of qubits are available\, they have the
principal advantage that they straightforwardly scale to higher dimension
s. A standard tool in the QC approach are Variational Quantum Simulations
(VQS) which form a class of hybrid quantum-classical algorithms for solvin
g optimization problems. For example\, the objective may be to find the gr
ound state of a Hamiltonian by minimizing the energy. As such\, VQS use pa
rametric quantum circuit designs to generate a family of quantum states (e
.g.\, states obeying physical symmetries) and efficiently evaluate a cost
function for the given set of variational parameters (e.g.\, energy of the
current quantum state) on a quantum device. The optimization is then perf
ormed using a classical feedback loop based on the measurement outcomes of
the quantum device.\n\nIn the case of energy minimization\, the optimal p
arameter set therefore encodes the ground state corresponding to the given
Hamiltonian provided that the parametric quantum circuit is able to encod
e the ground state. Hence\, the design of parametric quantum circuits is s
ubject to two competing drivers. On one hand\, the set of states\, that ca
n be generated by the parametric quantum circuit\, has to be large enough
to contain the ground state. On the other hand\, the circuit should contai
n as few quantum gates as possible to minimize noise from the quantum devi
ce. In other words\, when designing a parametric quantum circuit we want t
o ensure that there are no redundant parameters.\n\nIn this talk\, I will
consider the parametric quantum circuit as a map from parameter space to t
he state space of the quantum device. Using this point of view\, the set o
f generated states forms a manifold. If the quantum circuit is free from r
edundant parameters\, then the number of parameters is precisely the dimen
sion of the manifold of states. This leads us to the notion of dimensional
expressivity analysis. I will discuss means of analyzing a given parametr
ic design in order to remove redundant parameters as well as any unwanted
symmetries (e.g.\, a gate whose only effect is a change in global phase).
Time permitting\, I may discuss the manifold of physical states as well si
nce this will allow us to decide whether or not a parametric quantum circu
it can express all physical states (thereby ensuring that the ground state
can be expressed as well)."\n\nhttps://events.perimeterinstitute.ca/event
/2/contributions/10/
LOCATION:Perimeter Institute
URL:https://events.perimeterinstitute.ca/event/2/contributions/10/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Fun with replicas and holographic tensor networks
DTSTART;VALUE=DATE-TIME:20201117T140000Z
DTEND;VALUE=DATE-TIME:20201117T145000Z
DTSTAMP;VALUE=DATE-TIME:20210612T202506Z
UID:indico-contribution-2-6@events.perimeterinstitute.ca
DESCRIPTION:Speakers: Michael Walter (University of Amsterdam)\nhttps://ev
ents.perimeterinstitute.ca/event/2/contributions/6/
LOCATION:Perimeter Institute
URL:https://events.perimeterinstitute.ca/event/2/contributions/6/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Extracting universal data of critical quantum spin chains from per
iodic uniform matrix product states
DTSTART;VALUE=DATE-TIME:20201119T190000Z
DTEND;VALUE=DATE-TIME:20201119T195000Z
DTSTAMP;VALUE=DATE-TIME:20210612T202506Z
UID:indico-contribution-2-16@events.perimeterinstitute.ca
DESCRIPTION:Speakers: Yijian Zou (X\, the Moonshot Factory)\nWe explain ho
w periodic uniform matrix product states (puMPS) can be used to extract un
iversal data of critical quantum spin chains. We show that puMPS and puMPS
Bloch states accurately capture the ground state and low-energy excited s
tates of critical quantum spin chains up to several hundreds of spins. Thi
s enables us to extract (i) scaling dimensions\, conformal spins of scalin
g operators\, (ii) spectral renormalization group flows between CFTs\, (ii
i) lattice realizations of scaling operators\, and operator product expans
ion coefficients\, (iv) emergent symmetries such as superconformal symmetr
y\, and (v) universal tripartite entanglement of the ground state\, includ
ing entanglement of purification and reflected entropy. We give examples h
ow each of these is achieved and discuss potential applications to open pr
oblems.\n\nIn collaboration with Ash Milsted\, Mike Zaletel\, Guifre Vidal
\n\nhttps://events.perimeterinstitute.ca/event/2/contributions/16/
LOCATION:Perimeter Institute
URL:https://events.perimeterinstitute.ca/event/2/contributions/16/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Path-integral Optimization and AdS/CFT
DTSTART;VALUE=DATE-TIME:20201120T130000Z
DTEND;VALUE=DATE-TIME:20201120T135000Z
DTSTAMP;VALUE=DATE-TIME:20210612T202506Z
UID:indico-contribution-2-17@events.perimeterinstitute.ca
DESCRIPTION:Speakers: Tadashi Takayanagi (Yukawa Institute for Theoretica
l Physics)\nIn this talk we will start with a review of path-integraloptim
ization\, which provides a useful description of non-unitary tensor networ
ks for Euclidean path-integrals in CFTs. We will explain an emergence of A
dS geometry in this method and an interpretation as a computational comple
xity. Next we will give its application to analytical calculations of enta
nglement of purification\, which was quite recently reproduced by numerica
l calculations. Finally\, we would like to present a derivation of a path-
integral optimization method directly from the AdS/CFT.\n\nhttps://events.
perimeterinstitute.ca/event/2/contributions/17/
LOCATION:Perimeter Institute
URL:https://events.perimeterinstitute.ca/event/2/contributions/17/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Quantum Cellular Automata\, Tensor Networks\, and Area Laws
DTSTART;VALUE=DATE-TIME:20201117T130000Z
DTEND;VALUE=DATE-TIME:20201117T135000Z
DTSTAMP;VALUE=DATE-TIME:20210612T202506Z
UID:indico-contribution-2-5@events.perimeterinstitute.ca
DESCRIPTION:Speakers: Ignacio Cirac (Max Planck Institute of Quantum Optic
s)\nQuantum Cellular Automata are unitary maps that preserve locality and
respect causality. I will show that in one spatial dimension they correspo
nd to matrix product unitary operators\, and that one can classify them in
the presence of symmetries\, giving rise to phenomenon analogous to symme
try protection. I will then show that in higher dimensions\, they correspo
nd to other tensor networks that fulfill an extra condition and whose bond
dimension does not grow with the system size. As a result\, they satisfy
an area law for the entanglement entropy they can create. I will also defi
ne other classes of non-unitary maps\, the so-called quantum channels\, th
at either respect causality or preserve locality and show that\, whereas t
he latter obey an area law for the amount of quantum correlations they can
create\, as measured by the quantum mutual information\, the former may v
iolate it. Additionally\, neither of them can be expressed as tensor netwo
rks with a bond dimension that is independent of the system size.\n\nhttps
://events.perimeterinstitute.ca/event/2/contributions/5/
LOCATION:Perimeter Institute
URL:https://events.perimeterinstitute.ca/event/2/contributions/5/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Thirring model from tensor networks - phase structure and real-tim
e dynamics
DTSTART;VALUE=DATE-TIME:20201119T140000Z
DTEND;VALUE=DATE-TIME:20201119T145000Z
DTSTAMP;VALUE=DATE-TIME:20210612T202506Z
UID:indico-contribution-2-14@events.perimeterinstitute.ca
DESCRIPTION:Speakers: Krzysztof Cichy (Adam Mickiewicz University)\nIn th
is talk\, we report on our studies of the Thirring model using MPS techniq
ues. The Thirring model is a quantum field theory describing self-interact
ions of the Dirac field in 1+1 dimensions. It evinces a non-trivial zero-t
emperature phase structure in the mass-interaction plane\, with gapless (c
ritical) and gapped (massive) phases separated by a Berezinskii-Kosterlitz
-Thousless-type transition. To investigate this phase structure\, we exami
ned the entanglement entropy\, the fermion bilinear condensate and two typ
es of correlation functions. We also show our preliminary results of the r
eal-time dynamics of the Thirring model\, using variational uniform MPS an
d time-dependent variational principle.\nCo-Authors:\nMari Carmen Banuls\,
Max-Planck Institute of Quantum Optics\nHao-Ti Hung\, National Taiwan
University\nYing-Jer Kao\, National Taiwan University\nC.-J. David Lin\,
National Chiao-Tung University\nYu-Ping Lin\, University of Colorado at Bo
ulder\nAmit Singh\, National Chiao-Tung University\nDavid T. L. Tan\, Nati
onal Chiao-Tung University\n\nhttps://events.perimeterinstitute.ca/event/2
/contributions/14/
LOCATION:Perimeter Institute
URL:https://events.perimeterinstitute.ca/event/2/contributions/14/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Tensor network description of 3D Quantum Gravity and Diffeomorphi
sm Symmetry
DTSTART;VALUE=DATE-TIME:20201118T140000Z
DTEND;VALUE=DATE-TIME:20201118T145000Z
DTSTAMP;VALUE=DATE-TIME:20210612T202506Z
UID:indico-contribution-2-36@events.perimeterinstitute.ca
DESCRIPTION:Speakers: Bianca Dittrich (Perimeter Institute)\nIn contrast t
o the 4D case\, there are well understood theories of quantum gravity f
or the 3D case. Indeed\, 3D general relativity constitutes a topological
field theory (of BF or equivalently Chern-Simons type) and can be quanti
zed as such. The resulting quantum theory of gravity offers many interest
ing lessons for the 4D case. \n\nIn this talk I will discuss the quantum t
heory which results from quantizing 3D gravity as a topological field theo
ry. This will also allow a derivation of a holographic boundary theory\, t
ogether with a geometric interpretation of the boundary observables. \n\nT
he resulting structures can be interpreted in terms of tensor networks\, w
hich provide states of the boundary theory. \nI will explain how a choice
of network structure and bond dimensions constitutes a complete gauge fixi
ng of the diffeomorphism symmetry in the gravitational bulk system. The t
heory provides a consistent set of rules for changing the gauge fixing and
with it the tensor network structure. This provides an example of how dif
feomorphism symmetry can be realized in a tensor network based framework.\
n\nI will close with some remarks on the 4D case and the challenges we fac
e there.\n\nhttps://events.perimeterinstitute.ca/event/2/contributions/36/
LOCATION:Perimeter Institute
URL:https://events.perimeterinstitute.ca/event/2/contributions/36/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Custom Fermionic Codes for Quantum Simulation
DTSTART;VALUE=DATE-TIME:20201117T181500Z
DTEND;VALUE=DATE-TIME:20201117T183000Z
DTSTAMP;VALUE=DATE-TIME:20210612T202506Z
UID:indico-contribution-2-38@events.perimeterinstitute.ca
DESCRIPTION:Speakers: Riley Chien (Dartmouth College)\nhttps://events.peri
meterinstitute.ca/event/2/contributions/38/
LOCATION:Perimeter Institute
URL:https://events.perimeterinstitute.ca/event/2/contributions/38/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Quantum Extremal Islands Made Easy: Complexity on the brane
DTSTART;VALUE=DATE-TIME:20201117T183000Z
DTEND;VALUE=DATE-TIME:20201117T184500Z
DTSTAMP;VALUE=DATE-TIME:20210612T202506Z
UID:indico-contribution-2-39@events.perimeterinstitute.ca
DESCRIPTION:Speakers: Shan-Ming Ruan (Perimeter Institute)\nWe examine hol
ographic complexity in the doubly holographic model to study quantum extre
mal islands. We focus on the holographic complexity=volume (CV) proposal f
or boundary subregions in the island phase. Exploiting the Fefferman-Graha
m expansion of the metric and other geometric quantities near the brane\,
we derive the leading contributions to the complexity and interpret these
in terms of the generalized volume of the island derived from the higher c
urvature action for the brane gravity. Motivated by these results\, we pro
pose a generalization of the CV proposal for higher curvature theories of
gravity. Further\, we provide two consistency checks of our proposal by st
udying Gauss-Bonnet gravity and f(R) gravity in the bulk.\n\nhttps://event
s.perimeterinstitute.ca/event/2/contributions/39/
LOCATION:Perimeter Institute
URL:https://events.perimeterinstitute.ca/event/2/contributions/39/
END:VEVENT
BEGIN:VEVENT
SUMMARY:A measurement-based variational quantum eigensolver
DTSTART;VALUE=DATE-TIME:20201119T180000Z
DTEND;VALUE=DATE-TIME:20201119T185000Z
DTSTAMP;VALUE=DATE-TIME:20210612T202506Z
UID:indico-contribution-2-15@events.perimeterinstitute.ca
DESCRIPTION:Speakers: Luca Dellantonio (University of Waterloo)\nIn this t
alk I will speak about the meeting point of two models that have raised in
terest in the community in the last years. From one side\, we looked at me
asurement-based quantum computing (MBQC)\, which is an alternative to circ
uit-based quantum computing. Instead of modifying a state via gates\, MBQC
achieves the same result by measuring auxiliary qubits in a graph. From t
he other side\, we considered variational quantum eigensolvers (VQEs)\, th
at are one of the most successful tools for exploiting quantum computers i
n the NISQ era. In our work\, we present two measurement-based VQE schemes
. The first introduces a new approach for constructing variational familie
s. The second provides a translation of circuit-based to measurement-based
schemes. Both schemes offer problem-specific advantages in terms of the r
equired resources and coherence times. We apply them\, respectively\, to t
he Schwinger model and the two-dimensional Z(2) lattice gauge theory.\n\nh
ttps://events.perimeterinstitute.ca/event/2/contributions/15/
LOCATION:Perimeter Institute
URL:https://events.perimeterinstitute.ca/event/2/contributions/15/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Tensor networks for LGT: beyond 1D
DTSTART;VALUE=DATE-TIME:20201116T130000Z
DTEND;VALUE=DATE-TIME:20201116T135000Z
DTSTAMP;VALUE=DATE-TIME:20210612T202506Z
UID:indico-contribution-2-4@events.perimeterinstitute.ca
DESCRIPTION:Speakers: Mari-Carmen Banuls (Max Planck Institute of Quantum
Optics)\nThe suitability of tensor network ansatzes for the description of
physically relevant states in one dimensional lattice gauge theories (LGT
) has been demonstrated in the last years by a large amount of systematic
studies\, including abelian and non-abelian LGTs\, and including scenarios
where traditional Monte Carlo approaches fail due to a sign problem. Whil
e this establishes a solid motivation to extend the program to higher dime
nsions\, a similar systematic study in two dimensions using PEPS requires
dealing with specific considerations. Besides a larger computational costs
associated to the higher spatial dimension\, the presence of plaquette te
rms in LGTs hinders the efficiency of the most up-to-date PEPS algorithms.
With a newly developed update strategy\, nevertheless\, such terms can be
treated by the most efficient techniques. We have used this method to per
form the first ab initio iPEPS study of a LGT in 2+1 dimensions: a Z3 inva
riant model\, for which we have determined the phase diagram.\n\nhttps://e
vents.perimeterinstitute.ca/event/2/contributions/4/
LOCATION:Perimeter Institute
URL:https://events.perimeterinstitute.ca/event/2/contributions/4/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Towards a realistic holographic tensor network: From p-adic CFT to
(minimal) CFT2
DTSTART;VALUE=DATE-TIME:20201118T130000Z
DTEND;VALUE=DATE-TIME:20201118T135000Z
DTSTAMP;VALUE=DATE-TIME:20210612T202506Z
UID:indico-contribution-2-9@events.perimeterinstitute.ca
DESCRIPTION:Speakers: Ling-Yan Hung (Fudan University )\n"The success of t
he Ryu-Takayanagi formula suggests a profound connection between the AdS/C
FT correspondence and tensor networks.\nThere are since many works on cons
tructing examples\, although it is very difficult to make them explicit an
d quantitative. We will discuss some new progress in the toy example of p
-adic CFT where its tensor network dual was previously constructed explici
tly [ arXiv:1703.05445 \, arXiv:1812.06059\, arXiv:1902.01411]\, and how
some analogue of Einstein equation on the graph emerges as we consider RG
flow of these CFTs. \nThese progresses inspire us to find a way to constr
uct explicit holographic tensor networks of more realistic CFTs based on t
heir connection with topological models with one higher dimension\, at lea
st in CFT2. We will present some preliminary results and works in progress
."\n\nhttps://events.perimeterinstitute.ca/event/2/contributions/9/
LOCATION:Perimeter Institute
URL:https://events.perimeterinstitute.ca/event/2/contributions/9/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Query complexity and cutoffs in AdS3/CFT2
DTSTART;VALUE=DATE-TIME:20201119T130000Z
DTEND;VALUE=DATE-TIME:20201119T135000Z
DTSTAMP;VALUE=DATE-TIME:20210612T202506Z
UID:indico-contribution-2-13@events.perimeterinstitute.ca
DESCRIPTION:Speakers: Bartek Czech (Tsinghua University)\nA quantum state
is a map from operators to real numbers that are their expectation values.
Evaluating this map always entails using some algorithm\, for example con
tracting a tensor network. I propose a novel way of quantifying the comple
xity of a quantum state in terms of "query complexity": the number of time
s an efficient algorithm for computing correlation functions in the given
state calls a certain subroutine. I construct such an algorithm for a gene
ral "state at a cutoff" in 1+1-dimensional field theory. The algorithm sca
ns cutoff-sized intervals for operators whose expectation values will be c
omputed. It can be written as a Matrix Product State\, with individual mat
rices performing translations in the space of (cutoff-sized) intervals and
reading off consecutive operator inputs. If we take the queried subroutin
e to be a translation in the space of intervals\, query complexity counts
"how many" intervals the algorithm visits--a notion of distance in the spa
ce of intervals. A unique distance function is consistent with the requisi
te notion of translations\; therefore the query complexity of a state at a
cutoff is unambiguously defined. In holographic theories\, the query comp
lexity evaluates to the integral of the Ricci scalar on a spatial slice en
closed by the bulk cutoff\, which in pure AdS3 agrees with the volume prop
osal but otherwise departs from it.\n\nhttps://events.perimeterinstitute.c
a/event/2/contributions/13/
LOCATION:Perimeter Institute
URL:https://events.perimeterinstitute.ca/event/2/contributions/13/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ancilla qubit wavefunctions for the pseudogap metal phase of the c
uprates
DTSTART;VALUE=DATE-TIME:20201116T190000Z
DTEND;VALUE=DATE-TIME:20201116T195000Z
DTSTAMP;VALUE=DATE-TIME:20210612T202506Z
UID:indico-contribution-2-1@events.perimeterinstitute.ca
DESCRIPTION:Speakers: Subir Sachdev (Harvard University)\nThere is now sig
nificant experimental evidence that the physics of the underdoped cuprates
is controlled by a metallic state with a Fermi surface whose volume does
not equal the Luttinger value. However\, there has been no proposed wavefu
nction for such a state for electrons in a single band. I will describe a
wavefunction which involves tracing over 2 layers of ancilla qubits. The p
roposal also leads to a gauge theory for the transition to the conventiona
l Fermi liquid state found at large doping.\n\nhttps://events.perimeterins
titute.ca/event/2/contributions/1/
LOCATION:Perimeter Institute
URL:https://events.perimeterinstitute.ca/event/2/contributions/1/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Tensor network models of AdS/qCFT
DTSTART;VALUE=DATE-TIME:20201116T180000Z
DTEND;VALUE=DATE-TIME:20201116T185000Z
DTSTAMP;VALUE=DATE-TIME:20210612T202506Z
UID:indico-contribution-2-3@events.perimeterinstitute.ca
DESCRIPTION:Speakers: Jens Eisert (Free University of Berlin)\n"AdS/CFT en
dows gravity in anti-de Sitter (AdS) spacetime with a dual description in
certain conformal field theories (CFTs) with matching symmetries. Tensor n
etworks on regular discretizations of AdS space provide natural toy models
of AdS/CFT\, but break the continuous bulk symmetries. In this talk\, we
discuss several aspects of such toy models based on tensor networks. We sh
ow that this produces a quasiregular conformal field theory (qCFT) on the
boundary and rigorously compute its symmetries\, entanglement properties\,
and central charge bounds\, applicable to a wide range of existing models
. An explicit AdS/qCFT model with exact fractional central charges is give
n by holographic quantum error correcting codes based on Majorana dimers.
These models also realize the strong disorder renormalization group\, resu
lting in new connections between critical condensed-matter models\, exact
quantum error correction\, and holography. If time allows\, we will briefl
y review other recent group research on using tensor network models in qua
ntum many-body physics including many-body localization and time crystals
as well as in probabilistic modelling.\n\nBased on arXiv:2004.04173\, Phys
. Rev. A 102\, 042407 (2020)\, Phys. Rev. Research 1\, 033079 (2019)\, Sci
ence Advances 5\, eaaw0092 (2019)."\n\nhttps://events.perimeterinstitute.c
a/event/2/contributions/3/
LOCATION:Perimeter Institute
URL:https://events.perimeterinstitute.ca/event/2/contributions/3/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Noise-robustness and experimental data of wavelet-DMERA preparatio
n for critical Ising ground state
DTSTART;VALUE=DATE-TIME:20201117T184500Z
DTEND;VALUE=DATE-TIME:20201117T190000Z
DTSTAMP;VALUE=DATE-TIME:20210612T202506Z
UID:indico-contribution-2-54@events.perimeterinstitute.ca
DESCRIPTION:Speakers: Troy Sewell (University of Maryland)\nMulti-scale te
nsor networks offer a way to efficiently represent ground states of critic
al systems and may be adapted for state-preparation on a quantum computer.
The tensor network for a single scale specifies a quantum channel whose f
ixed-point is a subregion of the approximate critical ground state. The fi
xed-point of a noisy channel is perturbed linearly in the noise parameter
from the ideal state\, making local observables stable against errors for
these iterative algorithms. We consider the wavelet-designed circuit for
the 1+1D critical Ising ground state as a concrete example to numerically
test the noise robustness against our error models and compare the smalles
t instance case with an implementation on a present-day ion-trap quantum c
omputer.\n\nhttps://events.perimeterinstitute.ca/event/2/contributions/54/
LOCATION:Perimeter Institute
URL:https://events.perimeterinstitute.ca/event/2/contributions/54/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Tensor network methods for quantum chemistry
DTSTART;VALUE=DATE-TIME:20201117T190000Z
DTEND;VALUE=DATE-TIME:20201117T195000Z
DTSTAMP;VALUE=DATE-TIME:20210612T202506Z
UID:indico-contribution-2-11@events.perimeterinstitute.ca
DESCRIPTION:Speakers: Steven White (University of California\, Irvine)\nTh
e search for applications of quantum computers has highlighted the field o
f quantum chemistry\, where one can also apply tensor network methods. The
re are several challenges in getting useful results for molecules compared
to simulating a model Hamiltonian in condensed matter physics. The first
issue is in descretizing continuum space to get a finite Hamiltonian whic
h is amenable to tensor network techniques. Another is the need for high a
ccuracy\, particularly in energies\, to compare with experiments. I will
give an overview of the approaches used in this field\, and then focus on
our work using grid and wavelet-based discretizations coupled with DMRG me
thods.\n\nhttps://events.perimeterinstitute.ca/event/2/contributions/11/
LOCATION:Perimeter Institute
URL:https://events.perimeterinstitute.ca/event/2/contributions/11/
END:VEVENT
BEGIN:VEVENT
SUMMARY:A tensor-network approach to fixed-point models of topological pha
ses
DTSTART;VALUE=DATE-TIME:20201117T180000Z
DTEND;VALUE=DATE-TIME:20201117T181500Z
DTSTAMP;VALUE=DATE-TIME:20210612T202506Z
UID:indico-contribution-2-7@events.perimeterinstitute.ca
DESCRIPTION:Speakers: Andreas Bauer (Free University Berlin)\n"I will intr
oduce a tensor-network based language for classifying topological phases v
ia fixed-point models. The "models" will be tensor networks formalizing a
discrete Euclidean path integral living in a topological space-time\, and
can be obtained from Hamiltonian models by Trotterizing the imaginary time
evolution. Topological fixed-point models are invariant under topology-pr
eserving space-time deformations. Space-time manifolds and homeomorphisms
can be combinatorially represented by graph-like "networks"\, which togeth
er with "moves" form a "liquid". The networks can be interpreted as tensor
networks\, and the moves as equations which determine the fixed-point mod
els. Different combinatorial representations of the same space-times yield
new kinds of fixed-point models. Given the limited time\, I will stick to
very simple examples in 1+1 dimensions for this talk."\n\nhttps://events.
perimeterinstitute.ca/event/2/contributions/7/
LOCATION:Perimeter Institute
URL:https://events.perimeterinstitute.ca/event/2/contributions/7/
END:VEVENT
END:VCALENDAR