Quench dynamics of an ultracold Fermi gas in the BCS regime : Spectral properties and confinement-induced breakdown of the Higgs mode

Titelangaben

Hannibal, S. ; Kettmann, P. ; Croitoru, Mikhail D. ; Vagov, Alexei ; Axt, Vollrath M. ; Kuhn, Tilmann:
Quench dynamics of an ultracold Fermi gas in the BCS regime : Spectral properties and confinement-induced breakdown of the Higgs mode.
In: Physical Review A. Bd. 91 (2015) Heft 4 . - Art.Nr. 043630, 11 S..
ISSN 0556-2791
DOI: https://doi.org/10.1103/PhysRevA.91.043630

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Abstract

The Higgs amplitude mode of the order parameter of an ultracold confined Fermi gas in the BCS regime after a quench of the coupling constant is analyzed theoretically. A characteristic feature is a damped oscillation which at a certain transition time changes into a rather irregular dynamics. We compare the numerical solution of the full set of nonlinear equations of motion for the normal and anomalous Bogoliubov quasiparticle excitations with a linearized approximation. In doing so the transition time as well as the difference between resonant systems, i.e., systems where the Fermi energy is close to a sub-band minimum, and off-resonant systems can be well understood and traced back to the system and geometry parameters.