Coherence and Josephson oscillations between two tunnel-coupled one-dimensional atomic quasicondensates at finite temperature

TL;DR

This paper investigates how finite temperature affects coherence and Josephson oscillations in tunnel-coupled one-dimensional atomic quasicondensates, revealing thermal fluctuations can suppress these oscillations.

Contribution

It extends the theoretical understanding by calculating the relative-phase correlation function beyond the harmonic approximation at finite temperatures.

Findings

Thermal fluctuations reduce Josephson oscillation frequency.

Small tunnel coupling can lead to the disappearance of Josephson oscillations.

The study provides a more accurate description of coherence in atomic quasicondensates at finite temperature.

Abstract

We revisit the theory of tunnel-coupled atomic quasicondensates in double-well elongated traps at finite temperatures. Using the functional-integral approach, we calculate the relative-phase correlation function beyond the harmonic limit of small fluctuations of the relative phase and its conjugate relative-density variable. We show that the thermal fluctuations of the relative phase between the two quasicondensates decrease the frequency of Josephson oscillations and even wash out these oscillations for small values of the tunnel coupling.