Augustin Vanrietvelde - Causal decompositions of 1D quantum cellular automata, with a detour through a theory of quantum partitions

Wed, 15 May 2024 00:00:00 +0000

Causal decompositions of 1D quantum cellular automata, with a detour through a theory of quantum partitions

This seminar, given by Augustin Vanrietvelde, will happend on 15 May 2024, at 9:0. It will take place in Room Not specified.

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Abstract

The investigation of quantum theory’s causal structure has recently seen a surge in interest from the quantum foundations community, due to its ability to encapsulate the theory’s non-classical aspects. In that context, the conjecture of causal decompositions postulates an equivalence between a unitary channel’s causal structure (which of its inputs can affect which of its outputs) and its compositional structure (whether it can be written as the composition of smaller unitary operations along a certain graph). Because it would provide a one-to-one connection between an operational property and a mathematical structure, this conjecture would provide considerable leverage to better understand the nature of causal influences in the quantum realm. However, it has so far only been proven in a handful of cases. In this talk, I will herald major progress on that front, showing that all 1D Quantum Cellular Automata (which one can think of as discretised models of 1+1D Minkowksi spacetimes) are causally decomposable. I will also show how the statement and proof of this result make use of fundamental structures in the theory, namely C*-algebras, and how they led along the way to the development of a theory of quantum partitions with foundational interest of its own. (This is ongoing work with Pablo Arrighi and Octave Mestoudjian.)

Augustin Vanrietvelde | LIP6 - QI Team

Augustin Vanrietvelde - Causal decompositions of 1D quantum cellular automata, with a detour through a theory of quantum partitions

Causal decompositions of 1D quantum cellular automata, with a detour through a theory of quantum partitions

Abstract