Abstract

In classical causal modelling it is conventional to group together “indistinguishable” scenarios; that is, to use a single graphical model to represent all the different latent-variable structures that generate the same operationally testable predictions. Equivalence rules which hold in the classical setting, however, can break down in the quantum setting. I will discuss my group’s recent work regarding causal scenarios with intermediate latent variables, where different quantum structures can be distinguished in ways that have no classical analogue. I will summarize prior work establishing that replacing classical hidden common causes by quantum systems often broadens the set of correlations admitting causal explanation. I will then highlight that such “causal quantum-ization” fundamentally reorganizes the landscape of which causal structures are operationally distinguishable. To capture these new distinctions, we will leverage tools such as monogamy of nonlocal correlations and semidefinite-programming hierarchies. The talk will summarize arXiv:2412.10238, will introduce (unpublished!) results regarding the (astonishing!) causal utility of quantum secret sharing codes, and will conclude with some (tantalizing!) open questions.

About the speaker

"Elie Wolfe is a Research Scientist at the Perimeter Institute for Theoretical Physics. His research lies at the intersection of quantum foundations, information, and causality.  He studies diverse topics such as causal modelling, quantum networks, and contextuality, all through the unifying theme of distinguishing classical, quantum, and post-quantum operational theories.
Speaker profile photo: attached."