Titlebar

Export bibliographic data
Literature by the same author
plus on the publication server
plus at Google Scholar

 

Pure Goldstone mode in the quench dynamics of a confined ultracold Fermi gas in the BCS-BEC crossover regime

Title data

Kettmann, P. ; Hannibal, S. ; Croitoru, Mikhail D. ; Axt, Vollrath M. ; Kuhn, Tilmann:
Pure Goldstone mode in the quench dynamics of a confined ultracold Fermi gas in the BCS-BEC crossover regime.
In: Physical Review A. Vol. 96 (2017) Issue 3 . - Art.Nr. 033618, 14 S..
ISSN 0556-2791
DOI: https://doi.org/10.1103/PhysRevA.96.033618

Abstract in another language

We present a numerical study of the dynamic response of a confined superfluid Fermi gas to a rapid change of the scattering length (i.e., an interaction quench). Based on a fully microscopic time-dependent density-matrix approach within the full Bogoliubov–de Gennes formalism that includes a 3D harmonic confinement we simulate and identify the emergence of a Goldstone mode of the BCS gap in a cigar-shaped 6Li gas. By analyzing this Goldstone mode over a wide range of parameters, we show that its excitation spectrum is gapless and that its main frequency is not fixed by the trapping potential but that it is determined by the details of the quench. Thus we report the emergence of a pure Goldstone mode of the BCS gap that—in contrast to situations in many previous studies—maintains its gapless excitation spectrum predicted by the Goldstone theorem. Furthermore, we observe that the size-dependent superfluid resonances resulting from the atypical BCS-BEC crossover have a direct impact on this Goldstone mode. Finally, we find that the interaction quench-induced Goldstone mode leads to a low-frequency in-phase oscillation of the single-particle occupations with complete inversion of the lowest-lying single-particle states which could provide a convenient experimental access to the pure gapless Goldstone mode.

Further data

Item Type: Article in a journal
Refereed: Yes
Keywords: Goldstone mode; ultracold confined Fermi gas; BCS regime; quench dynamics; BCS-BEC crossover; Bogoliubov–de Gennes formalism; microscopic time-dependent density-matrix approach
Institutions of the University: Faculties > Faculty of Mathematics, Physics und Computer Science > Department of Physics
Faculties > Faculty of Mathematics, Physics und Computer Science > Department of Physics > Chair Theoretical Physics III > Chair Theoretical Physics III - Univ.-Prof. Dr. Martin Axt
Faculties
Faculties > Faculty of Mathematics, Physics und Computer Science
Faculties > Faculty of Mathematics, Physics und Computer Science > Department of Physics > Chair Theoretical Physics III
Result of work at the UBT: Yes
DDC Subjects: 500 Science > 530 Physics
Date Deposited: 06 Nov 2017 13:04
Last Modified: 06 Nov 2017 13:04
URI: https://eref.uni-bayreuth.de/id/eprint/40304