Victoria Wright (Quantinuum): Quantum field theory can be more contextual than non-relativistic quantum theory

Abstract: Quantum theory allows for correlations between spacelike separated experiments that go beyond the set of local realist correlations of classical physics. This phenomenon is often called Bell non-locality. However, since the resolution of Tsirelson’s conjecture we know that the set of quantum commuting correlations—that is identified by the mathematical framework of algebraic quantum field theory (AQFT)—is strictly larger than the (closure of the) set of quantum spatial correlations—that are allowed in non-relativistic quantum theory (NRQT). An experiment observing correlations beyond the quantum spatial set would greatly impact our understanding of nature. Currently, these correlations are difficult to identify, and it is not known whether any have a physical realisation. Both the theoretical and technological challenges to deciding these problems are great. In this talk I will consider the sets of correlations identified by the AQFT and NRQT formalisms for a different type of experiment: prepare-and-measure experiments known as (generalised) contextuality scenarios. One may initially expect that the relative simplicity of a prepare-and-measure experiment would not allow us to probe the distinction between AQFT and NRQT. Nonetheless, using the non-local case and a result about steering in C*-algebras, I will demonstrate that the set of potential AQFT correlations for contextuality scenarios is strictly larger than that of NRQFT. The simplicity of contextuality scenarios comes at the cost of requiring more assumptions about the experiment. However, this simplified setting may provide a more feasible testing ground for probing the difference in the predictions of AQFTs and NRQT both theoretically and experimentally.

Victoria Wright is a Senior Research Scientist in Theoretical Quantum Cryptography at Quantinuum.

Schedule

15:30-16:00 tea/coffee and pastries (LAK G.01)

16:00-17:30 seminar and Q&A (LAK 2.02)

17:30 onwards pub visit and dinner (depending on speaker’s availability)

This event will take place in person on LSE’s campus. However, those unable to attend in person will have the option of taking part online.

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