Spatial Dependence of Entropy in Trapped Ultracold Bose Gases

TL;DR

This paper uncovers a new self-organized phase in trapped ultracold Bose gases, characterized by non-local entropy signals indicating entanglement between distant superfluid regions, and suggests experimental methods to observe this phenomenon.

Contribution

It introduces a novel self-organized state in the Bose-Hubbard model with trap compression and analyzes entropy behaviors in this regime.

Findings

Identification of a self-organized phase with non-local entropy signals

Demonstration that a linear potential enhances observation of this phase

Analysis of quantum and thermal entropies showing different behaviors

Abstract

We find a new physical regime in the trapped Bose-Hubbard Hamiltonian using time-evolving block decimation. Between Mott-insulating and superfluid phases, the latter induced by trap compression, a spatially self-organized state appears in which non-local entropy signals entanglement between spatially distant superfluid shells. We suggest a linear rather than harmonic potential as an ideal way to observe such a self-organized system. We also explore both quantum information and thermal entropies in the superfluid regime, finding that while the former follows the density closely the latter can be strongly manipulated with the mean field.