Finite temperature effects in two-mode bosonic Josephson junctions

TL;DR

This paper investigates how finite temperature influences coherence and number fluctuations in a bosonic Josephson junction, revealing that under certain interactions, thermal effects can enhance coherence contrary to expectations.

Contribution

It provides a detailed analysis of temperature effects on coherence and fluctuations in a two-mode bosonic Josephson junction using the Bose-Hubbard model.

Findings

Thermal effects can increase coherence visibility.

Temperature can reduce on-site number fluctuations.

Counterintuitive effects depend on interaction strength.

Abstract

We analyze the effects of the temperature on a bosonic Josephson junction realized with ultracold and dilute atoms in a double-well potential. Starting from the eigenstates of the two-site Bose-Hubbard Hamiltonian, we calculate the coherence visibility and the fluctuation of the on-site occupation number and study them as functions of the temperature. We show that, contrary to naive expectations, when the boson-boson interaction is suitably chosen thermal effects can increase the coherence visibility and reduce the on-site number fluctuation.