Collective excitations of a trapped Fermi gas at finite temperature

Korolyuk, Anna; Kinnunen, Jami J.; Törmä, Païvi

doi:10.1103/physreva.89.013602

Cited by 7 publications

(8 citation statements)

References 37 publications

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“…This has been theoretically considered in the ultracold Fermi gas context in refs. [147,148,149,150,151] for trapped gases. The Leggett mode is a collective mode associated with pairing fluctuations of multiple bands, and a harmonic trap analogue of such mode was found in [148].…”

Section: Figure 17mentioning

confidence: 99%

The Fulde–Ferrell–Larkin–Ovchinnikov state for ultracold fermions in lattice and harmonic potentials: a review

et al. 2018

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We review the concepts and the present state of theoretical studies of spin-imbalanced superfluidity, in particular the elusive Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state, in the context of ultracold quantum gases. The comprehensive presentation of the theoretical basis for the FFLO state that we provide is useful also for research on the interplay between magnetism and superconductivity in other physical systems. We focus on settings that have been predicted to be favourable for the FFLO state, such as optical lattices in various dimensions and spin-orbit coupled systems. These are also the most likely systems for near-future experimental observation of the FFLO state. Theoretical bounds, such as Bloch's and Luttinger's theorems, and experimentally important limitations, such as finite-size effects and trapping potentials, are considered. In addition, we provide a comprehensive review of the various ideas presented for the observation of the FFLO state. We conclude our review with an analysis of the open questions related to the FFLO state, such as its stability, superfluid density, collective modes and extending the FFLO superfluid concept to new types of lattice systems.

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Section: Figure 17mentioning

confidence: 99%

The Fulde–Ferrell–Larkin–Ovchinnikov state for ultracold fermions in lattice and harmonic potentials: a review

et al. 2018

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“…24 for the spin current, eq. 26 for the current of the nematic tensor, the divergence of the momentum flux is presented in the Euler equation (28), its quantum part is proportional to the square of the Planck constant). Same structures can be approximately used for the normal fluid as the equations of state for the corresponding functions.…”

Section: Transition To the Two-fluid Hydrodynamicsmentioning

confidence: 99%

“…It includes the density waves [19], [20], [21] solitons [22], [23], [24], vortices [25], turbulence, shock waves [26], [27]. Collective excitations are considered in Fermi gas either [28]. These phenomena demonstrate more complex behavior in the spinor BECs in comparison with spin-0 BECs [4].…”

Section: Introductionmentioning

confidence: 99%

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Quantum hydrodynamics of the spinor Bose-Einstein condensate at non-zero temperatures

Andreev,

Mosaki,

Trukhanova

2021

Preprint

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Finite temperature hydrodynamic model is derived for the spin-1 ultracold bosons by the manyparticle quantum hydrodynamic method. It is presented as the two fluid model of the BEC and normal fluid. The linear and quadratic Zeeman effects are included. Scalar and spin-spin like shortrange interactions are considered in the first order by the interaction radius. It is also represented as the set of two nonlinear Pauli equations. The spectrum of the bulk collective excitations is considered for the ferromagnetic phase in the small temperature limit. The spin wave is not affected by the presence of the small temperature in the described minimal coupling model, where the thermal part of the spin-current of the normal fluid is neglected. The two sound waves are affected by the spin evolution in the same way as the change of spectrum of the single sound wave in BEC, where speed of sound is proportional to g1 + g2 with gi are the interaction constants.

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“…For small amplitude collective motions, such as breathing vibrations, QRPA (or linear response theory) can match the real-time dynamical results and is more efficient. Several QRPA calculations have been performed for Fermi gases, and interesting insights have been achieved in such as multipole collective modes [7,13], the Higgs modes [14], Goldstone modes [15,16], pairing breaking modes [16,17] and finite-size effects [18]. In addition, the transition currents in QRPA can directly reveal the dynamic mechanisms of collective modes [19].…”

Section: Introductionmentioning

confidence: 99%

Small-amplitude collective modes of a finite-size unitary Fermi gas in deformed traps

et al. 2019

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We have investigated collective breathing modes of a unitary Fermi gas in deformed harmonic traps. The ground state is studied by the Superfluid Local Density Approximation (SLDA) and small-amplitude collective modes are studied by the iterative Quasiparticle Random Phase Approximation (QRPA). The results illustrate the evolutions of collective modes of a small system in traps from spherical to elongated or pancake deformations. For small spherical systems, the influences of different SLDA parameters are significant, and, in particular, a large pairing strength can shift up the oscillation frequency of collective mode. The transition currents from QRPA show that the compressional flow patterns are nontrivial and dependent on the deformation. Finally, the finite size effects are demonstrated to be reasonable when progressing towards larger systems. Our studies indicate that experiments on small and medium systems are valuable for understanding effective interactions in systems with varying sizes and trap deformations.

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Collective excitations of a trapped Fermi gas at finite temperature

Cited by 7 publications

References 37 publications

The Fulde–Ferrell–Larkin–Ovchinnikov state for ultracold fermions in lattice and harmonic potentials: a review

The Fulde–Ferrell–Larkin–Ovchinnikov state for ultracold fermions in lattice and harmonic potentials: a review

Quantum hydrodynamics of the spinor Bose-Einstein condensate at non-zero temperatures

Small-amplitude collective modes of a finite-size unitary Fermi gas in deformed traps

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