Erratum: Extended Thomas-Fermi density functional for the unitary Fermi gas [Phys. Rev. A<b>78</b>, 053626 (2008)]

We compute the thermal conductivity and sound attenuation length of a dilute atomic Fermi gas in the framework of kinetic theory. Above the critical temperature for superfluidity, T c , the quasi-particles are fermions, whereas below T c , the dominant excitations are phonons. We calculate the thermal conductivity in both cases. We find that at unitarity the thermal conductivity κ in the normal phase scales as κ ∝ T 3/2 .In the superfluid phase we find κ ∝ T 2 . At high temperature the Prandtl number, the ratio of the momentum and thermal diffusion constants, is 2/3. The ratio increases as the temperature is lowered.As a consequence we expect sound attenuation in the normal phase just above T c to be dominated by shear viscosity. We comment on the possibility of extracting the shear viscosity of the dilute Fermi gas at unitarity using measurements of the sound absorption length.

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“…They find c 1 ≃ − √ 2/(30π 2 ξ 3/2 ) and c 2 ≃ 0, corresponding to γ = 1/(30mµ). Other estimates of γ can be found in [28][29][30].…”

Section: Elementary Excitationsmentioning

confidence: 99%

Thermal conductivity and sound attenuation in dilute atomic Fermi gases

2010

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“…By using a Madelung transformation, equations (1) and (2) can equivalently be written in the form of a time-dependent nonlinear Schrödinger equation (NLSE) [14] involving the complex order parameter Ψ(r, t) = n(r, t) e iθ(r,t) :…”

Section: Methods and Calculationsmentioning

confidence: 99%

“…The above equations describe accurately various static and dynamical properties of the UFG. The term multiplied by λ is found to be crucial to accurately describe surface effects, in particular in systems with a small number of atoms, where the Thomas-Fermi (local density) approximation fails [14]. We have shown that when fast dynamical processes occur and/or when shock waves come into play such term is necessary also in the large N limit [18], where results in quantitative agreement with experiments of real-time collision of strongly interacting Fermi gas clouds at unitarity [19] can be obtained [18].…”

Section: Introductionmentioning

confidence: 99%

“…Papenbrock and Bhattacharyya [13] have instead proposed a Kohn-Sham density functional with an effective mass to take into account nonlocality effects. Here we adopt instead the extended Thomas-Fermi functional of the UFG that we have proposed few years ago [14] and which has been used recently to successfully address a number of properties of such system [14][15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

“…Our extended Thomas-Fermi (ETF) density functional approach for the UFG [14,15] is based on the following extended hydrodynamics equations:…”

Section: Introductionmentioning

confidence: 99%

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Critical velocity, vortex shedding, and drag in a unitary Fermi superfluid

2013

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We study the real-time motion of a microscopic object in a cold Fermi gas at unitary conditions by using an extended Thomas-Fermi density functional approach. We find that spontaneous creation of singly quantized vortex-antivortex pairs occurs as a critical velocity is exceeded, which leads to a drag between the moving object and the Fermi gas. The resulting force is linear in the velocity for subsonic motion and becomes quadratic for supersonic motion.

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Surface effects in the unitary Fermi gas

2010

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We study the extended Thomas-Fermi (ETF) density functional of the superfluid unitary Fermi gas. This functional includes a gradient term which is essential to describe accurately the surface effects of the system, in particular with a small number of atoms, where the Thomas-Fermi (local density) approximation fails. We find that our ETF functional gives density profiles which are in good agreement with recent Monte Carlo results and also with a more sophisticated superfluid density functional based on Bogoliubov-de Gennes equations. In addition, by using extended hydrodynamics equations of superfluids, we calculate the frequencies of collective surface oscillations of the unitary Fermi gas, showing that quadrupole and octupole modes strongly depend on the number of trapped atoms. Density profile n(r) of the unitary Fermi gas with 20 atoms under harmonic confinement. Comparison among different theoretical predictions: our extended Thomas-Fermi (ETF) density functional, superfluid local density approximation (SLDA) density functional, and fixed-node diffusion Monte Carlo (FNDMC) calculatio

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Erratum: Extended Thomas-Fermi density functional for the unitary Fermi gas [Phys. Rev. A78, 053626 (2008)]

Cited by 44 publications

References 1 publication

Thermal conductivity and sound attenuation in dilute atomic Fermi gases

Thermal conductivity and sound attenuation in dilute atomic Fermi gases

Critical velocity, vortex shedding, and drag in a unitary Fermi superfluid

Surface effects in the unitary Fermi gas

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