Trap anharmonicity and sloshing mode of a Fermi gas

Pantel, Pierre-Alexandre; Davesne, D.; Chiacchiera, Silvia; Urban, Michael

doi:10.1103/physreva.86.023635

Cited by 19 publications

(38 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is therefore not obvious how one can generalize them to finite temperature. As it will be shown in a separate article [16], it is possible to recover the results of the present work in the T → 0 limit of the finite-temperature formalism if one includes the shift of the quasiparticle energies self-consistently into the Green's functions G 0 that build the ladder diagrams and the self-energy.…”

Section: Discussion Conclusion Outlookmentioning

confidence: 66%

“…In the T → 0 limit this implies that the ladders are calculated in a system whose Fermi momenta are different from the final ones. As it will be shown in a separate article [16], a finite-temperature formalism that includes the shift of the s.p. energies selfconsistently does not present the pathological behavior of the NSR scheme and reduces to the pp-RPA in the T → 0 limit.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Occupation numbers in strongly polarized Fermi gases and the Luttinger theorem

Urban

Schuck

2014

Phys. Rev. A

Self Cite

View full text Add to dashboard Cite

We study a two-component Fermi gas that is so strongly polarized that it remains normal fluid at zero temperature. We calculate the occupation numbers within the particle-particle random-phase approximation, which is similar to the Nozières-Schmitt-Rink approach. We show that the Luttinger theorem is fulfilled in this approach. We also study the change of the chemical potentials which allows us to extract, in the limit of extreme polarization, the polaron energy. [3]. In this theory, only equal densities of the two species forming the pairs (which we will denote by spin indices σ =↑, ↓) were considered. Nowadays, the crossover can be realized in experiments with ultracold trapped atoms whose scattering length a can be tuned with the help of a Feshbach resonance [4]. In these experiments, it is also possible to study systems with different densities of the two species, n ↑ = n ↓ [5]. In this way, one tries to discover, e.g., phases with exotic pairing, like the Fulde-Ferrel-Larkin-Ovchinnikov (FFLO) phase [6,7]. Also the extremely polarized case, where only a single particle of spin ↓ is put into a Fermi sea of spin ↑, bears interesting physics: when passing though the Feshbach resonance from the attractive (a < 0) to the repulsive (a > 0) side, one expects that the ground state transforms from a Fermi sea plus a fermionic quasiparticle, the so-called polaron, into a Fermi sea plus a bosonic molecule [8]. To our knowledge, there is so far no unique many-body theory that can describe the imbalanced Fermi gas in the cross-over and that reproduces in the limit of extreme polarization the polaronic and the molecular ground state, depending on the value of the scattering length a.As mentioned before, the original NSR theory was formulated in order to describe the BEC-BCS crossover in a two-component (σ =↑, ↓) Fermi gas with equal populations. Within this approach, the critical temperature T c as a function of the chemical potential µ is obtained from the Thouless criterion, i.e., it is the temperature where the in-medium T matrix develops a pole,where ω and k are, respectively, the total energy (measured from 2µ) and momentum of the pair, and Γ is ob- tained by summing ladder diagrams, see Fig. 1. As a function of µ, the critical temperature obtained in this way is exactly the same as within BCS theory. The difference between BCS and NSR comes from the inclusion of pair correlations into the relationship n(µ) between the number density and the chemical potential. This is done by including diagrams of the type shown in Fig. 2(a) into the thermodynamic potential Ω(µ, T ) and then computing the density from n = −∂Ω/∂µ. This is equivalent to calculating the density from [9]where ω n = nπT is a fermionic (n odd) Matsubara frequency and G is the single-particle (s.p.) Green's function with at most one self-energy insertion,

show abstract

Section: Discussion Conclusion Outlookmentioning

confidence: 66%

mentioning

confidence: 99%

Occupation numbers in strongly polarized Fermi gases and the Luttinger theorem

Urban

Schuck

2014

Phys. Rev. A

Self Cite

View full text Add to dashboard Cite

show abstract

“…In both cases self-similar solutions in power-law forms are found during the onset of the condensation, which exhibited turbulent type cascades. Also for cold atom systems the BEC formation has been studied [27,28] in a non-relativistic regime. In Refs.…”

Section: Introductionmentioning

confidence: 99%

Kinetic description of Bose-Einstein condensation with test particle simulations

Zhou

Zhuang

et al. 2017

Phys. Rev. D

View full text Add to dashboard Cite

We present a kinetic description of Bose-Einstein condensation for particle systems being out of thermal equilibrium, which may happen for gluons produced in the early stage of ultra-relativistic heavy-ion collisions. The dynamics of bosons towards equilibrium is described by a Boltzmann equation including Bose factors. To solve the Boltzmann equation with the presence of a Bose-Einstein condensate we make further developments of the kinetic transport model BAMPS (Boltzmann Approach of MultiParton Scatterings). In this work we demonstrate the correct numerical implementations by comparing the final numerical results to the expected solutions at thermal equilibrium for systems with and without the presence of Bose-Einstein condensate. In addition, the onset of the condensation in an over-populated gluon system is studied in more details. We find that both expected power-law scalings denoted by the particle and energy cascade are observed in the calculated gluon distribution function at infrared and intermediate momentum regions, respectively. Also, the time evolution of the hard scale exhibits a power-law scaling in a time window, which indicates that the distribution function is approximately self-similar during that time.

show abstract

“…In this article, we extend the method developed in [16] in order to simulate realistic systems (trap geometry and particle number). At the same time, we include in-medium effects into the calculation, namely the "mean-field" potential [15,24] and the in-medium crosssection [2,15,25,26], obtained within a T matrix theory.…”

Section: Introductionmentioning

confidence: 99%

Numerical solution of the Boltzmann equation for trapped Fermi gases with in-medium effects

2015

Self Cite

View full text Add to dashboard Cite

Using the test-particle method, we solve numerically the Boltzmann equation for an ultra-cold gas of trapped fermions with realistic particle number and trap geometry in the normal phase. We include a mean-field potential and in-medium modifications of the cross-section obtained within a T matrix formalism. After some tests showing the reliability of our procedure, we apply the method to realistic cases of practical interest, namely the anisotropic expansion of the cloud and the radial quadrupole mode oscillation. Our results are in good agreement with experimental data. Although the in-medium effects significantly increase the collision rate, we find that they have only a moderate effect on the anisotropic expansion and on frequency and damping rate of the quadrupole mode.

show abstract

Trap anharmonicity and sloshing mode of a Fermi gas

Cited by 19 publications

References 27 publications

Occupation numbers in strongly polarized Fermi gases and the Luttinger theorem

Occupation numbers in strongly polarized Fermi gases and the Luttinger theorem

Kinetic description of Bose-Einstein condensation with test particle simulations

Numerical solution of the Boltzmann equation for trapped Fermi gases with in-medium effects

Contact Info

Product

Resources

About