Frequency beating and damping of breathing oscillations of a harmonically trapped one-dimensional quasicondensate

Abstract

We study the breathing (monopole) oscillations and their damping in a harmonically trapped one-dimensional (1D) Bose gas in the quasicondensate regime using a finite-temperature classical field approach. By characterising the oscillations via the dynamics of the density profile's rms width over long time, we find that the rms width displays beating of two distinct frequencies. This means that 1D Bose gas oscillates not at a single breathing mode frequency, as found in previous studies, but as a superposition of two distinct breathing modes, one oscillating at frequency close to $\simeq \sqrt{3}\omega$ and the other at $\simeq 2\omega$, where $\omega$ is the trap frequency. The breathing mode at $\sim \sqrt{3}\omega$ dominates the beating at lower temperatures, deep in the quasicondensate regime, and can be attributed to the oscillations of the bulk of the density distribution comprised of particles populating low-energy, highly-occupied states. The breathing mode at $\simeq 2\omega$, on the other hand, dominates the beating at higher temperatures, close to the nearly ideal, degenerate Bose gas regime, and is attributed to the oscillations of the tails of the density distribution comprised of thermal particles in higher energy states. The two breathing modes have distinct damping rates, with the damping rate of the bulk component being approximately four times larger than that of the tails component.

16 pages, 12 figures

References in corpus (15)

• Thermalization and its mechanism for generic isolated quantum systems
• Experimental Observation of a Generalized Gibbs Ensemble
• Breakdown of thermalization in finite one-dimensional systems
• Dynamics and statistical mechanics of ultra-cold Bose gases using c-field techniques
• Bosonizing one-dimensional cold atomic gases
• Extension of Bogoliubov theory to quasi-condensates
• XMDS2: Fast, scalable simulation of coupled stochastic partial differential equations
• Breakdown of integrability in a quasi-one-dimensional ultracold bosonic gas
• Spatial nonlocal pair correlations in a repulsive 1D Bose gas
• Relaxation of a high-energy quasiparticle in a one-dimensional Bose gas
• Two-body momentum correlations in a weakly interacting one-dimensional Bose gas
• Numerical method for evolving the Projected Gross-Pitaevskii equation
• Hydrodynamic VS collisionless dynamics of a 1D harmonically trapped Bose gas
• Collapse and revival of the monopole mode of a degenerate Bose gas in an isotropic harmonic trap
• Dynamics of thermalization of two tunnel-coupled one-dimensional quasicondensates

Cited by in corpus (8)

• A finite-time quantum Otto engine with tunnel coupled one-dimensional Bose gases
• Loss induced collective mode in one-dimensional Bose gases
• Benchmarks of Generalized Hydrodynamics for 1D Bose Gases
• Maxwell relation between entropy and atom-atom pair correlation
• Out-of-equilibrium quantum thermochemical engine with one-dimensional Bose gas
• Fate of the "vacuum point'' and of grey solitons in dispersive quantum shock waves in a one-dimensional Bose gas
• Particle-hole origin of thermal beating in dipole-compression modes of a 1D Bose gas
• Controlled acoustic-driven vortex transport in coupled superfluid rings