Measurement of total phase fluctuation in cold-atomic quantum simulators

TL;DR

This paper introduces a method to measure total phase fluctuations in cold-atomic quantum simulators by reconstructing local currents, validated numerically and applied to experimental data, revealing insights into long-time dynamics.

Contribution

The paper presents a novel technique to extract total phase fluctuations from local current measurements, enhancing analysis of quantum many-body dynamics in cold-atom systems.

Findings

Successfully validated the method numerically.

Applied to experimental data from 1D Bose gases.

Revealed the hidden sector of the sum mode of the phase.

Abstract

Studying the dynamics of quantum many-body systems is often constrained by the limitations in probing relevant observables, especially in continuous systems. A powerful method to gain information about such systems is the reconstruction of local currents from the continuity equation. We show that this approach can be used to extract the total phase fluctuation of adjacent Bose gases. We validate our technique numerically and demonstrate its effectiveness by analyzing data from selected experiments simulating 1D quantum field theories through the phase difference of two parallel 1D Bose gases. This analysis reveals the previously hidden sector of the sum mode of the phase, which is important for studying long-time thermalization and out-of-equilibrium dynamics of the system. Our method is general and can be applied to other cold atom systems with spatial phase gradients, thereby expanding the scope and capabilities of cold-atomic quantum simulators.