Particle-hole origin of thermal beating in dipole-compression modes of a 1D Bose gas

Abstract

Using generalized hydrodynamics, we study the thermal behavior of dipole-compression collective oscillations in a harmonically trapped one-dimensional (1D) Bose gas across the crossover from weak to strong repulsive contact interactions. A key scale controlling this behavior is the temperature of the hole-induced anomaly, associated with the thermal population of hole excitations. In contrast to classical hydrodynamics, which predicts a single oscillation mode, we find a beating signal composed of two frequencies. As the temperature increases, both frequencies evolve from the low-temperature phononic hydrodynamic regime toward the collisionless limit around the anomaly temperature, without saturating at the values expected in the high-temperature collisional hydrodynamic regime. The lower frequency originates from hole excitations and is associated to low-energy oscillations, while the higher frequency emerges from particle excitations and corresponds to the dipole-compression mode. The thermal evolution of the relative excitation strengths of the two frequencies reflects the changing population imbalance between particle and hole spectral states across the anomaly. Our results reveal direct connections between excitations, thermodynamics, correlations, dynamics, and interparticle collisions, and may prove relevant to other atomic, nuclear, solid-state, electronic, and spin systems exhibiting similar anomalies or thermal second-order phase transitions.

Main Text: 5 pages, 2 figures, 1 table; Appendices: 3 pages, 2 figures, 1 table; Supplemental Material: 2 pages

References in corpus (18)

• Many-Body Physics with Ultracold Gases
• Thermalization and its mechanism for generic isolated quantum systems
• Non-equilibrium coherence dynamics in one-dimensional Bose gases
• Generalized hydrodynamics in strongly interacting 1D Bose gases
• Collective Modes in a Unitary Fermi Gas across the Superfluid Phase Transition
• Thermal instability, evaporation and thermodynamics of one-dimensional liquids in weakly-interacting Bose-Bose mixtures
• Luttinger liquid behavior of one-dimensional 3He
• Hydrodynamic VS collisionless dynamics of a 1D harmonically trapped Bose gas
• Probing the Degree of Coherence through the Full 1D to 3D crossover
• Analytic thermodynamic properties of the Lieb-Liniger gas
• Correlation properties of a one-dimensional repulsive Bose gas at finite temperature
• Thermometry of one-dimensional Bose gases with neural networks
• Benchmarks of Generalized Hydrodynamics for 1D Bose Gases
• Frequency beating and damping of breathing oscillations of a harmonically trapped one-dimensional quasicondensate
• Thermal fading of the $1/k^4$-tail of the momentum distribution induced by the hole anomaly
• The Theory of Generalised Hydrodynamics for the One-dimensional Bose Gas
• Collective excitations of a Bose-condensed gas: Fate of second sound in the crossover regime between hydrodynamic and collisionless regimes
• Dipole-Mode Spectrum and Hydrodynamic Crossover in a Resonantly Interacting Two-Species Fermion Mixture