Quenching small quantum gases: Genesis of the orthogonality catastrophe

TL;DR

This paper investigates the dynamical behavior of a small quantum gas system with an impurity, revealing signatures of Anderson's orthogonality catastrophe through numerical analysis of quenched interactions.

Contribution

It provides the first detailed numerical study of orthogonality catastrophe effects in a minimal two-boson system with an impurity under sudden interaction changes.

Findings

Evidence of orthogonality catastrophe in small quantum systems

Behavior of densities and entanglement shows orthogonality effects

Spectral functions indicate many-body orthogonality phenomena

Abstract

We study the dynamics of two strongly interacting bosons with an additional impurity atom trapped in a harmonic potential. Using exact numerical diagonalization we are able to fully explore the dynamical evolution when the interaction between the two distinct species is suddenly switched on (quenched). We examine the behavior of the densities, the entanglement, the Loschmidt echo and the spectral function for a large range of inter-species interactions and find that even in such small systems evidence of Anderson's orthogonality catastrophe can be witnessed.