Collapse and revival of the monopole mode of a degenerate Bose gas in an isotropic harmonic trap

Abstract

We study the monopole (breathing) mode of a finite temperature Bose-Einstein condensate in an isotropic harmonic trap recently developed by Lobser et al. [Nat. Phys. 11, 1009(2015]. We observe a nonexponential collapse of the amplitude of the condensate oscillation followed by a partial revival. This behavior is identified as being due to beating between two eigenmodes of the system, corresponding to in-phase and out-of-phase oscillations of the condensed and noncondensed fractions of the gas. We perform finite temperature simulations of the system dynamics using the Zaremba-Nikuni-Griffin methodology [J. Low Temp. Phys. 116, 277 (1999)], and find good agreement with the data, thus confirming the two mode description.

Static and dynamic properties of shell-shaped condensates

“…Thus, the work presented here provides a deeper understanding of physical mechanisms that result in signatures of the topological change in the shape of the BEC. Collective modes were the first phenomenon to be studied after the successful production of BECs and are well understood in the filled sphere case [43][44][45][46][47][48][49][50][51][52][53][54][55][56]; by taking the sphere as one limit in our family of BEC shapes, we show that the collective mode frequencies in the filled sphere and thin shell limits reflect the 3D and 2D limiting behaviors of the hollowing system. We additionally use an in situ numerical simulation of an experimental probe of collective modes to show that predicted hydrodynamic features in the spectra would in fact be relevant in experimental settings.…”

Collective many-body bounce in the breathing-mode oscillations of a Tonks-Girardeau gas

“…Collective dynamics can therefore serve as an important probe of the underlying interactions and is at the heart of a variety of nonequilibrium phenomena in many-body physics, including the archetypical examples of superfluidity and superconductivity. Among physical systems of current theoretical and experimental interest for understanding nonequilibrium many-body dynamics are ultracold quantum gases [1-10], which offer a versatile platform for realizing minimally complex but highly controllable models of many-body theory.In quantum gases, the simplest manifestations of collective dynamics relate to the frequencies of monopole (breathingmode) and multipole oscillations in harmonic trapping potentials [5,[11][12][13][14][15][16][17][18][19][20][21]. These frequencies, depending on trap configurations, can vary significantly from those of ideal (noninteracting) gases.…”

“…In quantum gases, the simplest manifestations of collective dynamics relate to the frequencies of monopole (breathingmode) and multipole oscillations in harmonic trapping potentials [5,[11][12][13][14][15][16][17][18][19][20][21]. These frequencies, depending on trap configurations, can vary significantly from those of ideal (noninteracting) gases.…”

A semiclassical field theory that is freed of the ultraviolet catastrophe

“…As a demonstration, we apply the regularized model to the famous case of the m = 0 collective mode [1], which has resisted all prior attempts at an effective field description for two decades [36,45,46]. Its correct description has become the standard litmus test for finite temperature field theories of the Bose gas.…”