Quench-induced collective excitations: From breathing to acoustic modes
Phys. Rev. A 113, 043308 – Published 6 April, 2026
DOI: https://doi.org/10.1103/qbkk-8z8r
Abstract
In trapped Bose-Einstein condensates, interaction quenches, which are abrupt changes of the interaction strength typically implemented via Feshbach tuning, are a practical and widely used protocol to address far-from-equilibrium collective modes. Using both numerical Gross-Pitaevskii and analytical schemes we study these interaction-quench-induced collective modes in a harmonically trapped two-dimensional Bose-Einstein condensate contrasting the behavior found at low and high energies. In the low-lying regime, we characterize realistic circumstances in which there is a breakdown of the expected scale invariance so that the collective excitations follow hydrodynamic theory instead of the predictions given by SO(2,1) conformal symmetry. In the high-energy regime, we focus on important trap effects associated with acoustic oscillations, which have been of interest experimentally. This comprehensive analysis of the collective excitations in trapped two-dimensional Bose-Einstein condensates is experimentally accessible. Through their frequencies and damping, this reflects an important built-in spectroscopy of such many-body states.
