Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Lecture notes in physics

BCS-BEC Crossover and the Spectrum of Collective Excitations in s-Wave and p-Wave Resonance Superfluids

M. Yu. Kagan

Published Jan 1, 2013• 1 citation
Publisher
DOI
10.1007/978-94-007-6961-8_7

Related papers

Collective Excitations in Superfluid Fermi Gases in the BCS-BEC Crossover

Guoxiang Huang

Understanding complex systems•Jan 1, 2013•0 citations

Collective Excitations of Trapped Superfluid Fermi Gases in a BCS-BEC Crossover with Arbitrary Atom Numbers

Chengtao Wang, Changru Ma, Yong-li Ma

Journal of Low Temperature Physics•Dec 23, 2008•5 citations

Excitations in the BCS–BEC crossover regime of a superfluid Fermi gas with a Feshbach resonance

Yoji Ohashi

Physica C Superconductivity•Apr 19, 2006•0 citations

Specific features of the BCS-BEC crossover and thermodynamics in the 2D resonant Fermi gas with p-wave pairing

M. Yu. Kagan, S. L. Ogarkov

The 2D resonant Fermi gas with p -wave pairing is considered n the BCS-BEC regime. For the 2D analog of the superfluid A1 phase, the Leggett equations [1] for superfluid gap Δ and chemical potential μ are analytically solved at T = 0 and the spectrum of the collective excitations (acoustic waves) is analyzed in the BCS regime (μ > 0), where the triplet Cooper pairs emerge; in the BEC regime (μ < 0), where the triplet local pairs (molecules) emerge; and in the transition region, where μ → 0. At low temperatures, the contribution of the superfluid Fermi quasiparticles of the resonant gas to heat capacity C v and the density of normal component ρ n is also calculated. At μ = 0, the fermionic contribution to ρ n and C v are represented as power functions of temperature (ρ n ∼ T 3 and C v ∼ T 2 ). However, similar power contributions to these quantities are related to phonons (bosonic acoustic oscillations). The possibility of the experimental observation of the nontrivial topological term with the charge Q = 1 in the BCS regime of the 2D A1 phase is briefly discussed.

Laser Physics•Apr 1, 2008•7 citations

BCS – BEC crossover, collective excitations, and hydrodynamics of superfluid quantum liquids and gases

M. Yu. Kagan, Andrei V. Turlapov

Abstract A Fermi gas described within the Bardeen–Cooper–Schrieffer (BCS) theory can be converted into a Bose–Einstein condensate (BEC) of composite molecules (dimers) by adiabatically tuning the interaction. The sequence of states that emerge in the process of such a conversion is referred to as the BCS–BEC crossover. We here review the theoretical and experimental results obtained for the BCS–BEC crossover in three- and quasi-two-dimensional quantum gases in the limiting geometry of traps and on optical lattices. We discuss nontrivial phenomena in the hydrodynamics of superfluid quantum gases and fluids, including the collective excitation spectrum in the BCS–BEC crossover, the hydrodynamics of rotating Bose condensates containing a large number of quantized vortices, and the intriguing problem of the chiral anomaly in the hydrodynamics of superfluid Fermi systems with an anisotropic p-wave pairing. We also analyze spin-imbalanced quantum gases and the potential to realize the triplet p-wave pairing via the Kohn–Luttinger mechanism in those gases. Recent results on two-dimensional Fermi-gas preparation and the observation of fluctuation phenomena related to the Berezinskii–Kosterlitz–Thouless transition in those gases are also reviewed. We briefly discuss the recent experimental discovery of the BCS–BEC crossover and anomalous superconductivity in bilayer graphene and the role of graphene, other Dirac semimetals (for example, bismuth), and 2D optical lattices as potential reference systems that exhibit all of the effects reviewed here.

Physics-Uspekhi•Nov 4, 2018•37 citations

Self consistent theories of superfluid density and collective modes in BCS-BEC

Rufus Boyack, Brandon Anderson, Chien‐Te Wu +1 more

Bulletin of the American Physical Society•Mar 17, 2016•0 citations
The 2D resonant Fermi gas with p -wave pairing is considered n the BCS-BEC regime. For the 2D analog of the superfluid A1 phase, the Leggett equations [1] for superfluid gap Δ and chemical potential μ are analytically solved at T = 0 and the spectrum of the collective excitations (acoustic waves) is analyzed in the BCS regime (μ > 0), where the triplet Cooper pairs emerge; in the BEC regime (μ < 0), where the triplet local pairs (molecules) emerge; and in the transition region, where μ → 0. At low temperatures, the contribution of the superfluid Fermi quasiparticles of the resonant gas to heat capacity C v and the density of normal component ρ n is also calculated. At μ = 0, the fermionic contribution to ρ n and C v are represented as power functions of temperature (ρ n ∼ T 3 and C v ∼ T 2 ). However, similar power contributions to these quantities are related to phonons (bosonic acoustic oscillations). The possibility of the experimental observation of the nontrivial topological term with the charge Q = 1 in the BCS regime of the 2D A1 phase is briefly discussed.
Abstract A Fermi gas described within the Bardeen–Cooper–Schrieffer (BCS) theory can be converted into a Bose–Einstein condensate (BEC) of composite molecules (dimers) by adiabatically tuning the interaction. The sequence of states that emerge in the process of such a conversion is referred to as the BCS–BEC crossover. We here review the theoretical and experimental results obtained for the BCS–BEC crossover in three- and quasi-two-dimensional quantum gases in the limiting geometry of traps and on optical lattices. We discuss nontrivial phenomena in the hydrodynamics of superfluid quantum gases and fluids, including the collective excitation spectrum in the BCS–BEC crossover, the hydrodynamics of rotating Bose condensates containing a large number of quantized vortices, and the intriguing problem of the chiral anomaly in the hydrodynamics of superfluid Fermi systems with an anisotropic p-wave pairing. We also analyze spin-imbalanced quantum gases and the potential to realize the triplet p-wave pairing via the Kohn–Luttinger mechanism in those gases. Recent results on two-dimensional Fermi-gas preparation and the observation of fluctuation phenomena related to the Berezinskii–Kosterlitz–Thouless transition in those gases are also reviewed. We briefly discuss the recent experimental discovery of the BCS–BEC crossover and anomalous superconductivity in bilayer graphene and the role of graphene, other Dirac semimetals (for example, bismuth), and 2D optical lattices as potential reference systems that exhibit all of the effects reviewed here.