Signatures of indistinguishability in bosonic many-body dynamics

TL;DR

This paper introduces a measure of bosonic indistinguishability that influences many-body dynamics and interference, revealing how it affects observable variances and interaction effects in multimode systems.

Contribution

It defines a new measure of bosonic indistinguishability and links it to observable dynamics in both non-interacting and interacting regimes.

Findings

Indistinguishability measure relates to variance of single-particle observables.

Interactions induce hierarchy of interference processes.

Indistinguishability affects expectation values even with interactions.

Abstract

The dynamics of bosons in generic multimode systems, such as Bose-Hubbard models, is not only determined by interactions among the particles, but also by their mutual indistinguishability manifested in many-particle interference. We introduce a measure of indistinguishability for Fock states of bosons whose mutual distinguishability is controlled by an internal degree of freedom. We demonstrate how this measure emerges both in the non-interacting and interacting evolution of observables. In particular, we find an unambiguous relationship between our measure and the variance of single-particle observables in the non-interacting limit. A non-vanishing interaction leads to a hierarchy of interaction-induced interference processes, such that even the expectation value of single-particle observables is influenced by the degree of indistinguishability.