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Persistent oscillations of the order parameter and interaction quench phase diagram for a confined Bardeen-Cooper-Schrieffer Fermi gas

Titelangaben

Hannibal, S. ; Kettmann, P. ; Croitoru, Mikhail D. ; Axt, Vollrath Martin ; Kuhn, T.:
Persistent oscillations of the order parameter and interaction quench phase diagram for a confined Bardeen-Cooper-Schrieffer Fermi gas.
In: Physical Review A. Bd. 98 (November 2018) Heft 5 . - Eintrag 053605.
ISSN 0556-2791
DOI: https://doi.org/10.1103/PhysRevA.98.053605

Abstract

We present a numerical study of the interaction quench dynamics in a superfluid ultracold Fermi gas confined in a three-dimensional cigar-shaped harmonic trap. In the present paper, we investigate the amplitude mode of the superfluid order parameter after interaction quenches, which start deep in the BCS phase and end in the BCS-BEC-crossover regime. To this end, we exploit the Bogoliubov–de Gennes formalism, which takes the confinement potential explicitly into account and provides a microscopic fully coherent description of the system. We find an anharmonic nonlinear oscillation of the modulus of the superfluid order parameter, i.e., of the Higgs mode. This oscillation persists for large times with only a small amplitude modulation being visible. We connect the frequency and the mean value of this oscillation with the breaking of Cooper pairs in the superfluid phase. Additionally, we demonstrate that the occurrence of this persistent oscillation is connected to the onset of chaotic dynamics in our model. Finally, we calculate an interaction quench phase diagram of the Higgs mode for quenches on the BCS side of the BCS-BEC crossover and discuss its properties as a function of the aspect ratio of the cigar-shaped trap.

Weitere Angaben

Publikationsform: Artikel in einer Zeitschrift
Begutachteter Beitrag: Ja
Keywords: Higgs mode; ultracold confined Fermi gas; BCS regime; quench dynamics; nonlinear order parameter oscillations; chaotic dynamics; BCS-BEC crossover, Bogoliubov–de Gennes formalism; microscopic time-dependent density-matrix approach
Fachklassifikationen: condensed matter physics (theoretical)
Institutionen der Universität: Fakultäten > Fakultät für Mathematik, Physik und Informatik > Physikalisches Institut
Fakultäten > Fakultät für Mathematik, Physik und Informatik > Physikalisches Institut > Lehrstuhl Theoretische Physik III > Lehrstuhl Theoretische Physik III - Univ.-Prof. Dr. Martin Axt
Fakultäten
Fakultäten > Fakultät für Mathematik, Physik und Informatik
Fakultäten > Fakultät für Mathematik, Physik und Informatik > Physikalisches Institut > Lehrstuhl Theoretische Physik III
Titel an der UBT entstanden: Ja
Themengebiete aus DDC: 500 Naturwissenschaften und Mathematik > 530 Physik
Eingestellt am: 14 Nov 2018 07:35
Letzte Änderung: 14 Nov 2018 07:35
URI: https://eref.uni-bayreuth.de/id/eprint/46317