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BEGIN:VEVENT
SUMMARY:Welcome and Opening Remarks
DTSTART:20230417T133000Z
DTEND:20230417T140000Z
DTSTAMP:20240524T032200Z
UID:indico-contribution-574@events.perimeterinstitute.ca
DESCRIPTION:Speakers: Elie Wolfe (Perimeter Institute)\n\nhttps://events.p
erimeterinstitute.ca/event/38/contributions/574/
LOCATION:PI/4-405 - Bob Room (Perimeter Institute for Theoretical Physics)
URL:https://events.perimeterinstitute.ca/event/38/contributions/574/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Tutorial 1
DTSTART:20230417T140000Z
DTEND:20230417T150000Z
DTSTAMP:20240524T032200Z
UID:indico-contribution-575@events.perimeterinstitute.ca
DESCRIPTION:Speakers: Robert Spekkens (Perimeter Institute)\n\nhttps://eve
nts.perimeterinstitute.ca/event/38/contributions/575/
LOCATION:PI/4-405 - Bob Room (Perimeter Institute for Theoretical Physics)
URL:https://events.perimeterinstitute.ca/event/38/contributions/575/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Graphical models: fundamentals\, origins\, and beyond
DTSTART:20230417T153000Z
DTEND:20230417T160000Z
DTSTAMP:20240524T032200Z
UID:indico-contribution-576@events.perimeterinstitute.ca
DESCRIPTION:Speakers: Steffen Lauritzen (University of Copenhagen)\n\nThe
lecture will give a brief introduction to graphical models\, their origins
in Physics\, Genetics\, and Econometrics\, their modern usages\, and some
future perspectives.\n\nhttps://events.perimeterinstitute.ca/event/38/con
tributions/576/
LOCATION:PI/4-405 - Bob Room (Perimeter Institute for Theoretical Physics)
URL:https://events.perimeterinstitute.ca/event/38/contributions/576/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Tutorial 2
DTSTART:20230417T180000Z
DTEND:20230417T190000Z
DTSTAMP:20240524T032200Z
UID:indico-contribution-578@events.perimeterinstitute.ca
DESCRIPTION:Speakers: Ilya Shpitser (Johns Hopkins University)\n\nhttps://
events.perimeterinstitute.ca/event/38/contributions/578/
LOCATION:PI/4-405 - Bob Room (Perimeter Institute for Theoretical Physics)
URL:https://events.perimeterinstitute.ca/event/38/contributions/578/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Half-Trek Criterion for Identifiability of Latent Variable Models
DTSTART:20230421T133000Z
DTEND:20230421T140000Z
DTSTAMP:20240524T032200Z
UID:indico-contribution-596@events.perimeterinstitute.ca
DESCRIPTION:Speakers: Mathias Drton (Technical University Munich)\n\n"Line
ar structural equation models relate random variables of interest via a li
near equation system that features stochastic noise. The models are natur
ally represented by directed graphs whose edges indicate non-zero coeffici
ents in the linear equations. In this talk I will report on progress on c
ombinatorial conditions for parameter identifiability in models with laten
t (i.e.\, unobserved) variables. Identifiability holds if the coefficient
s associated with the edges of the graph can be uniquely recovered from th
e covariance matrix they define.\n\nPaper: \nhttps://doi.org/10.1214/22-A
OS2221 or\nhttps://arxiv.org/abs/2201.04457"\n\nhttps://events.perimeterin
stitute.ca/event/38/contributions/596/
LOCATION:PI/4-405 - Bob Room (Perimeter Institute for Theoretical Physics)
URL:https://events.perimeterinstitute.ca/event/38/contributions/596/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Correlations from joint measurements in boxworld and applications
to information processing
DTSTART:20230417T193000Z
DTEND:20230417T200000Z
DTSTAMP:20240524T032200Z
UID:indico-contribution-579@events.perimeterinstitute.ca
DESCRIPTION:Speakers: Mirjam Weilenmann (Institute for Quantum Optics and
Quantum Information)\n\nQuantum measurements have been a central topic of
research in quantum theory for many years. In the context of causal struc
tures and communication over networks\, we are often particularly interest
ed in local measurements of subsystems of a multi-partite system and class
ical processing of their inputs and outcomes. Formally\, this processing c
an often be described by means of maps that are known as wirings. These wi
rings are furthermore interesting for the analysis of generalized probabil
istic theories\, as they are shared by all of them. In this work\, we expl
icitly characterise all possible mulitpartite measurements in the generali
sed probabilistic theory box-world for various numbers of parties n with s
ystems characterised by n_i fiducial measurements (which can be thought of
as inputs here) and n_o outcomes\, for small n\, n_i\, n_o. This include
s all n-party n_i-input\, n_o-outcome wirings. For n > 2\, we further clas
sify these measurements into three classes: wirings\, deterministic non-wi
ring type and non-deterministic non-wiring type measurements. We explore a
dvantages of these different types of measurements over previous protocols
in the context of non-locality distillation and state-distingishability.
We further find examples of non-locality without entanglement (contrary to
previous claims) and a relation of these measurements to classical proces
s matrices.\n\nhttps://events.perimeterinstitute.ca/event/38/contributions
/579/
LOCATION:PI/4-405 - Bob Room (Perimeter Institute for Theoretical Physics)
URL:https://events.perimeterinstitute.ca/event/38/contributions/579/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Entropic Inequality Constraints from e-separation Relations in Dir
ected Acyclic Graphs with Hidden Variables
DTSTART:20230417T203000Z
DTEND:20230417T210000Z
DTSTAMP:20240524T032200Z
UID:indico-contribution-581@events.perimeterinstitute.ca
DESCRIPTION:Speakers: Beata Zjawin (Gdansk University)\n\nWhen some variab
les in a directed acyclic graph (DAG) are hidden\, a notoriously complicat
ed set of constraints on the distribution of observed variables is implied
. In this talk\, we present inequality constraints implied by graphical cr
iteria in hidden variable DAGs. The constraints can intuitively be underst
ood to follow from the fact that the capacity of variables along a causal
pathway to convey information is restricted by their entropy. For DAGs tha
t exhibit e-separation relations\, we present entropic inequality constrai
nts and we show how they can be used to learn about the true causal model
from an observed data distribution (arXiv:2107.07087).\n\nhttps://events.p
erimeterinstitute.ca/event/38/contributions/581/
LOCATION:PI/4-405 - Bob Room (Perimeter Institute for Theoretical Physics)
URL:https://events.perimeterinstitute.ca/event/38/contributions/581/
END:VEVENT
BEGIN:VEVENT
SUMMARY:A quantum tale of causes and effects
DTSTART:20230419T180000Z
DTEND:20230419T190000Z
DTSTAMP:20240524T032200Z
UID:indico-contribution-589@events.perimeterinstitute.ca
DESCRIPTION:Speakers: Rafael Chaves (Federal University of Rio Grande do
Norte)\n\nExplaining the natural world through cause-and-effect relations
is the fundamental principle of science. Although a classical theory of ca
usality has been recently introduced\, enabling us to model causation acro
ss diverse research fields\, it is crucial to examine which aspects of it
require modification or abandonment to also comprehend causality in the qu
antum world. To address this question\, we will investigate paradigmatic s
cenarios\, including the double slit\, Bell's theorem and generalizations
to quantum networks\, also exploring recent experimental advancements.\n\n
https://events.perimeterinstitute.ca/event/38/contributions/589/
LOCATION:PI/1-100 - Theatre (Perimeter Institute for Theoretical Physics)
URL:https://events.perimeterinstitute.ca/event/38/contributions/589/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Observational Equivalences Between Causal Structures with Latent V
ariables
DTSTART:20230417T200000Z
DTEND:20230417T203000Z
DTSTAMP:20240524T032200Z
UID:indico-contribution-580@events.perimeterinstitute.ca
DESCRIPTION:Speakers: Marina Maciel Ansanelli (Perimeter Institute)\n\n"I
f one only performs experiments involving passive observations\, in genera
l there are multiple causal structures that can explain the same set of di
stributions over the observed variables. In this case\, we say that these
causal structures are observationally equivalent. In this work\, we explor
e all the known techniques for proving observational equivalence or inequi
valence\, as well as some original ones. \nEven if the existing rules are
not enough to achieve the full classification of the causal structures wit
h four observed variables\, our results get close to such classification a
nd show that admitting inequality constraints is a generic feature among s
tructures with four observed variables."\n\nhttps://events.perimeterinstit
ute.ca/event/38/contributions/580/
LOCATION:PI/4-405 - Bob Room (Perimeter Institute for Theoretical Physics)
URL:https://events.perimeterinstitute.ca/event/38/contributions/580/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Communication Genuine Multipartite Nonlocality as a benchmark for
large nonclassicality
DTSTART:20230418T133000Z
DTEND:20230418T140000Z
DTSTAMP:20240524T032200Z
UID:indico-contribution-582@events.perimeterinstitute.ca
DESCRIPTION:Speakers: Marc-Olivier Renou (Institute of Photonic Sciences)
\n\n"Quantum computing requires the ability to manipulate large nonclassic
al quantum systems. As we are far from any useful quantum computing advant
age\, certifying this ability is an important benchmark to assess progress
toward this goal. This can be done using the nonlocal nature of quantum c
orrelations\, which allows to certify a non-trusted experimental apparatus
from its input/output behaviour in a device independent way. It first req
uires to introduce the concept of Genuine Multipartite Nonlocality (GMNL)
of size n\, which designate systems which nonlocality cannot be understood
an obtained from many states composed of n − 1 (or less) constituents.\
n\nThe first historical definition of GMNL\, proposed by Svetlichny\, is i
ll-defined when used to assess the large nonclassical nature of quantum sy
stems\, as it predicts that maximal GMNL states can be obtain from biparti
te sources only. A more appropriate re-definition of that concept\, called
LOSR-GMNL\, was proposed recently [arXiv:2105.09381]. However\, it is not
satisfactory in all experimental situations\, as it cannot (by design) ca
pture potential communications between the systems which could occur in so
me realistic experimental systems (e.g.\, many-body systems) – which Sve
tlichny definition captures in a naïve way.\n\nIn this talk\, I will prop
ose a new alternative re-definition solving this issue\, called Communicat
ion-Genuine Multipartite Nonlocality of length t (C-GMNL). It is based on
a model inspired from synchronous distributed computing\, that involves t
communications steps along a graph.\n\nI will show that (i) the GHZ state
is maximally nonlocal according to this C-GMNL definition\, (ii) the clust
er state is trivial in this C-GMNL definition but that (iii) the cluster s
tate is maximally difficult in the LOSR-GMNL definition. Hence\, some comp
licated LOSR-GMNL states become trivial when a small amount of communicati
on is allowed.\n\nBased on a joint work in preparation with Xavier Coiteux
-Roy\, Owidiusz Makuta\, Fionnuala Curran\, Remigiusz Augusiak."\n\nhttps:
//events.perimeterinstitute.ca/event/38/contributions/582/
LOCATION:PI/4-405 - Bob Room (Perimeter Institute for Theoretical Physics)
URL:https://events.perimeterinstitute.ca/event/38/contributions/582/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Separation of quantum\, spatial quantum and approximate quantum co
rrelations
DTSTART:20230418T140000Z
DTEND:20230418T143000Z
DTSTAMP:20240524T032200Z
UID:indico-contribution-583@events.perimeterinstitute.ca
DESCRIPTION:Speakers: Salman Beigi (Institute for Research in Fundamental
Sciences)\n\nQuantum nonlocal correlations are generated by implementation
of local quantum measurements on spatially separated quantum subsystems.
Depending on the underlying mathematical model and the dimension of the un
derlying Hilbert spaces\, various notions of sets of quantum correlations
can be defined. This talk is devoted to the separations of some of these s
ets via simple ideas in quantum information theory\, namely self-testing a
nd entanglement embezzlement.\n\nhttps://events.perimeterinstitute.ca/even
t/38/contributions/583/
LOCATION:PI/4-405 - Bob Room (Perimeter Institute for Theoretical Physics)
URL:https://events.perimeterinstitute.ca/event/38/contributions/583/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Causal Scenarios: the Interesting\, the Boring and the Elusive
DTSTART:20230418T150000Z
DTEND:20230418T153000Z
DTSTAMP:20240524T032200Z
UID:indico-contribution-584@events.perimeterinstitute.ca
DESCRIPTION:Speakers: Matthew Pusey (University of York)\n\nI will sketch
the current state of play with classifying causal scenarios (aka DAGs wit
h latent variables). Some are interesting: the classical correlations are
constrained by non-trivial inequalities such as Bell’s. Some are boring:
the classical correlations are constrained only by observable conditional
independencies. Some we still don’t know. Along the way I will mention
joint work with Joe Henson\, Ray Lal\, Shashaank Khanna\, Marina Ansanelli
and Elie Wolfe\, and disjoint work by Robin Evans.\n\nhttps://events.peri
meterinstitute.ca/event/38/contributions/584/
LOCATION:PI/4-405 - Bob Room (Perimeter Institute for Theoretical Physics)
URL:https://events.perimeterinstitute.ca/event/38/contributions/584/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Causal Discovery via Common Entropy
DTSTART:20230418T180000Z
DTEND:20230418T183000Z
DTSTAMP:20240524T032200Z
UID:indico-contribution-585@events.perimeterinstitute.ca
DESCRIPTION:Speakers: Murat Kocaoglu (Purdue University)\n\nDistinguishing
causation from correlation from observational data requires assumptions.
We consider the setting where the unobserved confounder between two observ
ed variables is simple in an information-theoretic sense\, captured by its
entropy. When the observed dependence is not due to causation\, there exi
sts a small-entropy variable that can make the observed variables conditio
nally independent. The smallest such entropy is known as common entropy in
information theory. We extend this notion to Renyi common entropy by mini
mizing the Renyi entropy of the latent variable. We establish identifiabil
ity results with Renyi-0 common entropy\, and a special case of (binary) R
enyi-1 common entropy. To efficiently compute common entropy\, we propose
an iterative algorithm that can be used to discover the trade-off between
the entropy of the latent variable and the conditional mutual information
of the observed variables. We show that our algorithm can be used to disti
nguish causation from correlation in such simple two-variable systems. Add
itionally\, we show that common entropy can be used to improve constraint-
based methods such as the PC algorithm in the small-sample regime\, where
such methods are known to struggle. We propose modifying these constraint-
based methods to assess if a separating set found by these algorithms is v
alid using common entropy. We finally evaluate our algorithms on synthetic
and real data to establish their performance.\n\nhttps://events.perimeter
institute.ca/event/38/contributions/585/
LOCATION:PI/4-405 - Bob Room (Perimeter Institute for Theoretical Physics)
URL:https://events.perimeterinstitute.ca/event/38/contributions/585/
END:VEVENT
BEGIN:VEVENT
SUMMARY:A Hierarchy of Multi-Party Nonlocal Effects
DTSTART:20230419T133000Z
DTEND:20230419T140000Z
DTSTAMP:20240524T032200Z
UID:indico-contribution-587@events.perimeterinstitute.ca
DESCRIPTION:Speakers: Peter Bierhorst (University of New Orleans)\n\nAccor
ding to recent new definitions\, a multi-party behavior is genuinely multi
partite nonlocal (GMNL) if it cannot be modeled by measurements on an unde
rlying network of bipartite-only nonlocal resources\, possibly supplemente
d with local (classical) resources shared by all parties. Three experiment
al results published in 2022 provide initial evidence\, subject to postsel
ection-related assumptions\, for the existence of behaviors meeting these
definitions of GMNL. The new definitions of GMNL differ on whether to allo
w entangled measurements upon\, and/or superquantum behaviors among\, the
underlying bipartite resources when classifying behaviors asonly bipart
ite nonlocal. I will discuss the interrelationships of these choices in th
ree-party quantum networks\, and present a behavior in the simplest nontri
vial multi-partite measurement scenario (3 parties\, 2 measurement setting
s\, and 2 outcomes) that (A) cannot be simulated in a bipartite network pr
ohibiting both entangled measurements and superquantum resources\, (B) can
be simulated with bipartite-only quantum states allowing for an entangled
quantum measurement (indicating an approach to device independent certifi
cation of entangled measurements with fewer settings than in previous prot
ocols)\, and surprisingly (C) can be simulated with bipartite-only superqu
antum states (Popescu-Rohrlich boxes) while maintaining a prohibition on e
ntangled measurements. It turns out that other behaviors previously studie
d as device-independent witnesses of entangled measurements can also be si
mulated in the manner of (C)\, posing a challenge to a theory-independent
understanding of entangled measurements as an observable phenomenon distin
ct from bipartite nonlocality.\n\nhttps://events.perimeterinstitute.ca/eve
nt/38/contributions/587/
LOCATION:PI/4-405 - Bob Room (Perimeter Institute for Theoretical Physics)
URL:https://events.perimeterinstitute.ca/event/38/contributions/587/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Bounding counterfactual distributions in discrete structural causa
l models
DTSTART:20230419T193000Z
DTEND:20230419T200000Z
DTSTAMP:20240524T032200Z
UID:indico-contribution-590@events.perimeterinstitute.ca
DESCRIPTION:Speakers: Jin Tian (Iowa State University)\n\nWe investigate t
he problem of bounding counterfactual queries from an arbitrary collection
of observational and experimental distributions and qualitative knowledge
about the underlying data-generating model represented in the form of a c
ausal diagram. We show that all counterfactual distributions in an arbitra
ry structural causal model (SCM) with finite discrete endogenous variables
could be generated by a family of SCMs with the same causal diagram where
unobserved (exogenous) variables are discrete with a finite domain. Utili
zing this family of SCMs\, we translate the problem of bounding counterfac
tuals into that of polynomial programming whose solution provides optimal
bounds for the counterfactual query.\n\nhttps://events.perimeterinstitute.
ca/event/38/contributions/590/
LOCATION:PI/4-405 - Bob Room (Perimeter Institute for Theoretical Physics)
URL:https://events.perimeterinstitute.ca/event/38/contributions/590/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Quantum entropic causal inference
DTSTART:20230419T200000Z
DTEND:20230419T203000Z
DTSTAMP:20240524T032200Z
UID:indico-contribution-591@events.perimeterinstitute.ca
DESCRIPTION:Speakers: Vaneet Aggarwal (Purdue University)\, Zubin Jacob (P
urdue University)\n\nThe class of problems in causal inference which seeks
to isolate causal correlations solely from observational data even withou
t interventions has come to the forefront of machine learning\, neuroscien
ce and social sciences. As new large scale quantum systems go online\, it
opens interesting questions of whether a quantum framework exists on isola
ting causal correlations without any interventions on a quantum system. We
put forth a theoretical framework for merging quantum information science
and causal inference by exploiting entropic principles. At the root of ou
r approach is the proposition that the true causal direction minimizes the
entropy of exogenous variables in a non-local hidden variable theory. The
proposed framework uses a quantum causal structural equation model to bui
ld the connection between two fields: entropic causal inference and the qu
antum marginal problem. First\, inspired by the definition of geometric qu
antum discord\, we fill the gap between classical and quantum conditional
density matrices to define quantum causal models. Subsequently\, using a g
reedy approach\, we develop a scalable algorithm for quantum entropic caus
al inference unifying classical and quantum causality in a principled way.
We apply our proposed algorithm to an experimentally relevant scenario of
identifying the subsystem impacted by noise starting from an entangled st
ate. This successful inference on a synthetic quantum dataset can have pra
ctical applications in identifying originators of malicious activity on fu
ture multi-node quantum networks as well as quantum error correction. As q
uantum datasets and systems grow in complexity\, our framework can play a
foundational role in bringing observational causal inference from the clas
sical to the quantum domain.\n\nhttps://events.perimeterinstitute.ca/event
/38/contributions/591/
LOCATION:PI/4-405 - Bob Room (Perimeter Institute for Theoretical Physics)
URL:https://events.perimeterinstitute.ca/event/38/contributions/591/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Towards standard imsets for maximal ancestral graphs
DTSTART:20230417T160000Z
DTEND:20230417T163000Z
DTSTAMP:20240524T032200Z
UID:indico-contribution-577@events.perimeterinstitute.ca
DESCRIPTION:Speakers: Robin Evans (University of Oxford)\n\n"Imsets\, int
roduced by Studený (see Studený\, 2005 for details)\, are an algebraic m
ethod for representing conditional independence models. They have many att
ractive properties when applied to such models\, and they are particularly
nice when applied to directed acyclic graph (DAG) models. In particular\,
the standard imset for a DAG is in one-to-one correspondence with the ind
ependence model it induces\, and hence is a label for its Markov equivalen
ce class. We present a proposed extension to standard imsets for maximal a
ncestral graph (MAG) models\, which have directed and bidirected edges\, u
sing the parameterizing set representation of Hu and Evans (2020). By cons
truction\, our imset also represents the Markov equivalence class of the M
AG. \n\nWe show that for many such graphs our proposed imset defines the m
odel\, though there is a subclass of graphs for which the representation d
oes not. We prove that it does work for MAGs that include models with no a
djacent bidirected edges\, as well as for a large class of purely bidirect
ed models. If there is time\, we will also discuss applications of imsets
to structure learning in MAGs. \n\nThis is joint work with Zhongyi Hu (Oxf
ord).\n\nReferences \n\nZ. Hu and R.J. Evans\, Faster algorithms for Marko
v equivalence\, In Proceedings for the 36th Conference on Uncertainty in A
rtificial Intelligence (UAI-2020)\, 2020. \n\nM. Studený\, Probabilistic
Conditional Independence Structures\, Springer-Verlag\, 2005."\n\nhttps://
events.perimeterinstitute.ca/event/38/contributions/577/
LOCATION:PI/4-405 - Bob Room (Perimeter Institute for Theoretical Physics)
URL:https://events.perimeterinstitute.ca/event/38/contributions/577/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Panel Discussion
DTSTART:20230421T180000Z
DTEND:20230421T190000Z
DTSTAMP:20240524T032200Z
UID:indico-contribution-598@events.perimeterinstitute.ca
DESCRIPTION:Speakers: Sonia Markes (University of Toronto)\n\nhttps://even
ts.perimeterinstitute.ca/event/38/contributions/598/
LOCATION:PI/4-405 - Bob Room (Perimeter Institute for Theoretical Physics)
URL:https://events.perimeterinstitute.ca/event/38/contributions/598/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Some applications of Causal Inference in the real world
DTSTART:20230421T140000Z
DTEND:20230421T143000Z
DTSTAMP:20240524T032200Z
UID:indico-contribution-597@events.perimeterinstitute.ca
DESCRIPTION:Speakers: Ciaran Gilligan-Lee (Spotify and University College
London)\n\nCausal reasoning is vital for effective reasoning in many domai
ns\, from healthcare to economics. In medical diagnosis\, for example\, a
doctor aims to explain a patient’s symptoms by determining the diseases
causing them. This is because causal relations\, unlike correlations\, all
ow one to reason about the consequences of possible treatments and to answ
er counterfactual queries. In this talk I will present two recent causal i
nference projects done with my collaborators deriving new algorithms to so
lve problems that arise when applying causal inference in the real world.\
n\nhttps://events.perimeterinstitute.ca/event/38/contributions/597/
LOCATION:PI/4-405 - Bob Room (Perimeter Institute for Theoretical Physics)
URL:https://events.perimeterinstitute.ca/event/38/contributions/597/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Conditional Independence - Revisited
DTSTART:20230419T140000Z
DTEND:20230419T143000Z
DTSTAMP:20240524T032200Z
UID:indico-contribution-588@events.perimeterinstitute.ca
DESCRIPTION:Speakers: Patrick Forre (Universiteit van Amsterdam)\n\n"Many
relationships in causality\, statistics or probability theory can be expre
ssed as conditional independence relations between the occurring random va
riables. Since the invention of the notion of conditional independence one
aim was to be able to also express such relationship between random and n
on-random variables\, like the parameters of a stochastic model\, the inpu
t variables of a probabilistic program or intervention variables in a caus
al model. Over time several different versions of such extended conditiona
l independence notion have been proposed\, each coming with their own adva
ntages and disadvantages\, oftentimes limited to certain subclasses of ran
dom variables like discrete variables or ones with densities.\nIn this tal
k we present another such notion of conditional independence\, which can e
asily be expressed in measure-theoretic generality and even in categorical
probability. We will study its expressivity\, present its (convenient) pr
operties\, and relate it to other notions of conditional independence."\n\
nhttps://events.perimeterinstitute.ca/event/38/contributions/588/
LOCATION:PI/4-405 - Bob Room (Perimeter Institute for Theoretical Physics)
URL:https://events.perimeterinstitute.ca/event/38/contributions/588/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Is causal optimization polynomial optimization?
DTSTART:20230420T133000Z
DTEND:20230420T140000Z
DTSTAMP:20240524T032200Z
UID:indico-contribution-593@events.perimeterinstitute.ca
DESCRIPTION:Speakers: David Gross (University of Cologne)\n\n"Is there a
complete semi-definite programming hierarchy for quantum causal problems?
We divide the question into two parts. First: Can quantum causal problems
be expressed as polynomial optimization problems (this talk). Second: Can
this class of polynomial optimizations be solved by means of SDPs (Laurens
' talk). The optimizations we consider here are ""polynomial"" in two ways
. They are over the unknown observable algebra of the hidden systems\, whi
ch are specified by non-commutative polynomials in a set of generators. Bu
t they also involve independence constraints\, which are commutative polyn
omials in the state. A hierarchy\nof such polynomial tests is complete if
one can construct a quantum model for any observed distribution that passe
s all of them. We've recently had some success in finding such constructio
ns\, but also ran into problems in the general case [1\, 2]. I give a high
-level presentation of the state of the play.\n\n[1] https://arxiv.org/abs
/2110.14659\n[2] https://arxiv.org/abs/2212.11299"\n\nhttps://events.perim
eterinstitute.ca/event/38/contributions/593/
LOCATION:PI/4-405 - Bob Room (Perimeter Institute for Theoretical Physics)
URL:https://events.perimeterinstitute.ca/event/38/contributions/593/
END:VEVENT
BEGIN:VEVENT
SUMMARY:SDP approaches for quantum polynomial optimization
DTSTART:20230420T140000Z
DTEND:20230420T143000Z
DTSTAMP:20240524T032200Z
UID:indico-contribution-594@events.perimeterinstitute.ca
DESCRIPTION:Speakers: Laurens Ligthart (University of Cologne)\n\n"Many re
levant tasks in Quantum Information processing can be expressed as polynom
ial optimization problems over states and operators. In the earlier talk b
y David\, we saw that this is also the case for certain (quantum) causal c
ompatibility and causal optimization problems.\nThis talk will focus on se
veral closely related semidefinite programming (SDP) hierarchies that have
recently been shown to be complete for such polynomial optimization probl
ems [arxiv:2110.14659\, 2212.11299\, 2301.12513]. We give a high-level ove
rview of the techniques and mathematics that are needed for proving such s
tatements. In particular\, we will see a version of a Quantum De Finetti t
heorem\, as well as a sketch of a constructive proof of convergence for th
e SDP hierarchies. Afterwards\, these results are linked back to the causa
l compatibility problem to conclude that such SDP hierarchies are complete
for a certain type of causal structures known as tree networks."\n\nhttps
://events.perimeterinstitute.ca/event/38/contributions/594/
LOCATION:PI/4-405 - Bob Room (Perimeter Institute for Theoretical Physics)
URL:https://events.perimeterinstitute.ca/event/38/contributions/594/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Causal-model approach to extended contextuality
DTSTART:20230420T183000Z
DTEND:20230420T190000Z
DTSTAMP:20240524T032200Z
UID:indico-contribution-600@events.perimeterinstitute.ca
DESCRIPTION:Speakers: Matt Jones (University of Colorado)\n\nThere has bee
n recent interest in extending the concept of contextuality to cases of di
sturbance or inconsistent connectedness. This talk will describe an approa
ch using probabilistic causal models\, which generalize the hidden-variabl
es models of Bell and Kochen & Specker\, following recent work by Cavalcan
ti. I first prove an equivalence between three conditions on an arbitrary
measurement system: (1) existence of a model minimizing all causal influen
ces of context upon measurement outcomes\, (2) prohibition of a form of "h
idden" causal influence\, and (3) noncontextuality as defined in the Conte
xtuality-by-Default (CbD) theory of Dzhafarov and Kujala. The no-hidden-in
fluence principle thus confers a physical interpretation to CbD-contextual
ity\, paralleling Bell's local causality and Kochen & Specker's classical
embeddability. I then extend this analysis to other causal graph topologie
s\, showing that different graphs yield different notions of contextuality
\, but only the one corresponding to CbD agrees with traditional contextua
lity when restricted to non-disturbing systems.\n\nhttps://events.perimete
rinstitute.ca/event/38/contributions/600/
LOCATION:PI/4-405 - Bob Room (Perimeter Institute for Theoretical Physics)
URL:https://events.perimeterinstitute.ca/event/38/contributions/600/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Certifying long-range quantum correlations through routed Bell exp
eriments
DTSTART:20230420T180000Z
DTEND:20230420T183000Z
DTSTAMP:20240524T032200Z
UID:indico-contribution-595@events.perimeterinstitute.ca
DESCRIPTION:Speakers: Stefano Pironio (Université Libre de Bruxelles)\n\
nIn a recent paper\, Chaturvedi et al considered the interesting idea of r
outed Bell experiments. These are Bell experiments where Bob can measure h
is quantum particles at two distinct locations\, one close to the source a
nd another far away. This can be accomplished in the lab by using a switch
that directs Bob's quantum particle either to the nearby measurement devi
ce or to the distant one\, depending on a classical input chosen by Bob. C
haturvedi et al argue that there exists in such experiments a tradeoff bet
ween short-range and long-range correlations and that high-quality CHSH te
sts close to the source (which are achievable with current technology) low
er the requirements for witnessing nonlocality faraway from the source\, a
nd in particular increase their tolerance to particle losses. We criticall
y review their results and present a simple counterexample to it. We then
introduce a class of hybrid quantum-classical models\, which we refer to a
s "short-range quantum models". These models suitably capture the tradeoff
between short-range and long-range correlations in routed Bell experiment
s. Using our definition\, we explore new nonlocal tests in which high-qual
ity short-range correlations lead to weakened conditions for long-range te
sts. Although we do find improvements\, they are significantly smaller tha
n those claimed by CVP.\n\nhttps://events.perimeterinstitute.ca/event/38/c
ontributions/595/
LOCATION:PI/4-405 - Bob Room (Perimeter Institute for Theoretical Physics)
URL:https://events.perimeterinstitute.ca/event/38/contributions/595/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Latent variable justifies the stronger instrumental variable bound
s
DTSTART:20230419T203000Z
DTEND:20230419T210000Z
DTSTAMP:20240524T032200Z
UID:indico-contribution-592@events.perimeterinstitute.ca
DESCRIPTION:Speakers: Richard Guo (University of Cambridge)\n\nFor binary
instrumental variable models\, there seems to be a long-standing gap betw
een two sets of bounds on the average treatment effect: the stronger Balke
–Pearl ("sharp") bounds versus the weaker Robins–Manski ("natural") bo
unds. In the literature\, the Balke–Pearl bounds are typically derived u
nder stronger assumptions\, i.e.\, either individual exclusion or joint ex
ogeneity\, which are untestable cross-world statements\, while the natural
bounds only require testable assumptions. In this talk\, I show that the
stronger bounds are justified by the existence of a latent confounder. In
fact\, the Balke–Pearl bounds are sharp under latent confounding and sto
chastic exclusion. The "secret sauce" that closes this gap is a set of CHS
H-type inequalities that generalize Bell's (1964) inequality.\n\nhttps://e
vents.perimeterinstitute.ca/event/38/contributions/592/
LOCATION:PI/4-405 - Bob Room (Perimeter Institute for Theoretical Physics)
URL:https://events.perimeterinstitute.ca/event/38/contributions/592/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Quantum causal inference in the presence of hidden common causes:
An entropic approach
DTSTART:20230418T183000Z
DTEND:20230418T190000Z
DTSTAMP:20240524T032200Z
UID:indico-contribution-601@events.perimeterinstitute.ca
DESCRIPTION:Speakers: Mohammad Ali Javidian (Appalachian State University)
\n\nQuantum causality is an emerging field of study which has the potentia
l to greatly advance our understanding of quantum systems. In this paper\,
we put forth a theoretical framework for merging quantum information scie
nce and causal inference by exploiting entropic principles. For this purpo
se\, we leverage the tradeoff between the entropy of hidden cause and the
conditional mutual information of observed variables to develop a scalable
algorithmic approach for inferring causality in the presence of latent co
nfounders (common causes) in quantum systems. As an application\, we consi
der a system of three entangled qubits and transmit the second and third q
ubits over separate noisy quantum channels. In this model\, we validate th
at the first qubit is a latent confounder and the common cause of the seco
nd and third qubits. In contrast\, when two entangled qubits are prepared
and one of them is sent over a noisy channel\, there is no common confound
er. We also demonstrate that the proposed approach outperforms the results
of classical causal inference for the Tubingen database when the variable
s are classical by exploiting quantum dependence between variables through
density matrices rather than joint probability distributions.\n\nhttps://
events.perimeterinstitute.ca/event/38/contributions/601/
LOCATION:PI/4-405 - Bob Room (Perimeter Institute for Theoretical Physics)
URL:https://events.perimeterinstitute.ca/event/38/contributions/601/
END:VEVENT
END:VCALENDAR