Excitation Spectrum and Superfluid Gap of an Ultracold Fermi Gas

Biss, Hauke; Sobirey, Lennart; Luick, Niclas; Bohlen, Markus; Kinnunen, Jami J.; Bruun, Georg M.; Lompe, Thomas; Moritz, Henning

doi:10.1103/physrevlett.128.100401

Cited by 43 publications

(14 citation statements)

References 56 publications

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“…In 2022 Braidotti, et al measured Penrose Superradiance in a photon superfluid [89]. Biss, et al used ultracold Fermi gases with tunable interactions realized the BEC-BCS crossover from a Bose-Einstein condensate (BEC) of molecules to a Bardeen-Cooper-Schrieffer (BCS) superfluid of weakly bound Cooper pairs, and measured the full momentum-resolved low-energy excitation spectrum of strongly interacting ultracold Fermi gases, and calculation better agreement with data [90]. Yu, et al found the exact propagating topological solitons in the easy-plane phase of ferromagnetic spin-1 Bose-Einstein condensates, manifesting themselves as kinks in the transverse magnetization.…”

Section: Superfluidity and Becmentioning

confidence: 96%

Research of Theory on High Temperature Superconductivity, Super Fluidity and BEC

Yi-Fang¹

2022

PSBJ

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First, some progress of high-temperature superconductivity is discussed. Then we research its theory, including the extensive quantum theory, soliton solution, bag model and so on. Third, superfluidity and Bose-Einstein condensation (BEC), etc., are searched, such as the double solution of soliton-chaos in nonlinear equations. Finally, we predict existences of the hightemperature superfluidity and BEC, etc., and discuss some problems.

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Section: Superfluidity and Becmentioning

confidence: 96%

Research of Theory on High Temperature Superconductivity, Super Fluidity and BEC

Yi-Fang¹

2022

PSBJ

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“…We note that, in the normal state the first sound density response at different wavenumbers has been recently investigated by the NCSU group [80,81]. The sound velocity and damping rate of zero sound in the collisionless regime have been studied by several experimental groups [82,83] and have been theoretically addressed [84,85].…”

Section: B From the Collisionless To Hydrodynamic Regimementioning

confidence: 98%

Second sound with ultracold atoms: A brief historical account

Hu,

Yao,

Liu

2022

Preprint

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We briefly review the research on second sound in ultracold atomic physics, with emphasis on strongly interacting unitary Fermi gases with infinitely large s-wave scattering length. Second sound is a smoking-gun feature of superfluidity in any quantum superfluids. The observation and characterization of second sound in ultracold quantum gases has been a long-standing challenge, and in recent years there are rapid developments due to the experimental realization of a uniform box-trap potential. The purpose of this review is to present a brief historical account of the key research activities on second sound over the past two decades. We summarize the initial theoretical works that reveal the characteristics of second sound in a unitary Fermi gas, and introduce its first observation in a highly elongated harmonic trap. We then discuss the most recent measurement on second sound attenuation in a uniform setup, which may open a new era to understand quantum transport near quantum criticality in the strongly interacting regime. The observation of second sound in homogeneous weakly interacting Bose condensates in both two and three dimensions are also briefly introduced.

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“…The hopping gives rise to a single particle band of width W , and characterized by a semi-circular density of states. This model has been studied in thermal equilibrium [57] in the context of the BCS to BEC superfluidity crossover [58][59][60][61], while its dynamics has received attention recently [62][63][64][65][66][67][68] and revealed a variety of dynamical phase transitions. Here we focus on an open quantum system setting in which the evolution of the system density matrix ρ(t) is described by a Lindblad master equation [69], ( = 1),…”

Section: Introduction -mentioning

confidence: 99%

Dissipative Dynamics of a Fermionic Superfluid with Two-Body Losses

Mazza,

Schirò

2022

Preprint

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We study the dissipative dynamics of a fermionic superfluid in presence of two-body losses. We use a variational approach for the Lindblad dynamics and obtain dynamical equations for Anderson's pseudo-spins where dissipation enters as a complex pairing interaction as well as effective, densitydependent, single particle losses which break the conservation of the pseudo-spin norm. We show that this latter has key consequences on the dynamical behavior of the system. In the case of a sudden switching of the two-body losses we show that the superfluid order parameter decays much faster than then particle density at short times and eventually slows-down, setting into a power-law decay at longer time scales driven by the depletion of the system. We then consider a quench of pairing interaction, leading to coherent oscillations in the unitary case, followed by the switching of the dissipation. We show that losses wash away the dynamical BCS synchronization by introducing not only damping but also a renormalization of the frequency of coherent oscillations, which depends strongly from the rate of two-body losses.

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Excitation Spectrum and Superfluid Gap of an Ultracold Fermi Gas

Cited by 43 publications

References 56 publications

Research of Theory on High Temperature Superconductivity, Super Fluidity and BEC

Research of Theory on High Temperature Superconductivity, Super Fluidity and BEC

Second sound with ultracold atoms: A brief historical account

Dissipative Dynamics of a Fermionic Superfluid with Two-Body Losses

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