Equilibration and locality

TL;DR

This paper explores how the evolution to equilibrium relates to strong-locality in quantum mechanics, revealing differences between distinguishable and indistinguishable particles using a novel Markov-chain framework.

Contribution

It introduces a new Markov-chain framework to analyze strong-locality and equilibrium, highlighting differences between particle types and conditions for locality preservation.

Findings

Only distinguishable particles can evolve to equilibrium without breaking microstate symmetry.

Models can obey or violate strong-locality for both particle types.

Results may shed light on rapid equilibration in high-energy nuclear collisions.

Abstract

Experiments motivated by predictions of quantum mechanics indicate non-trivial correlations between spacelike-separated measurements. The phenomenon is referred to as a violation of strong-locality and, after Einstein, called ghostly action at a distance. An intriguing and previously unasked question is how the evolution of an assembly of particles to equilibrium-state relates to strong-locality. More specifically, whether, with this respect, indistinguishable particles differ from distinguishable ones. To address the question, we introduce a Markov-chain based framework over a finite set of microstates. For the first time, we formulate conditions needed to obey the particle transport- and strong-locality for indistinguishable particles. Models which obey transport-locality and lead to equilibrium-state are considered. We show that it is possible to construct models obeying and violating strong-locality both for indistinguishable particles and for distinguishable ones. However, we find that only for distinguishable particles strongly-local evolution to equilibrium is possible without breaking the microstate-symmetry. This is the strongest symmetry one can impose and leads to the shortest equilibration time. We hope that the results presented here may provide a new perspective on a violation of strong-locality, and the developed framework will help in future studies. Specifically they may help to interpret results on high-energy nuclear collisions indicating a fast equilibration of indistinguishable particles.