Thermal and Magnetic Properties of Dilute Solutions of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow><mml:mi mathvariant="normal">He</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msup></mml:mrow></mml:math>in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow><mml:mi mathvariant="normal">He</mml:mi></mml:mrow><mml:mrow><mml:mn>4</mml:mn></mml:mrow></mml:msup></mml:mrow></mml:math>a

Anderson, A. C.; Edwards, D. O.; Roach, W. R.; Sarwinski, R. E.; Wheatley, J. C.

doi:10.1103/physrevlett.17.367

Cited by 170 publications

(28 citation statements)

References 10 publications

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“…The predicted temperature dependence of Landau's Fermi liquid parameters, namely, the diffusion coefficient (D ∼ T −2 ), the thermal conductivity (κ ∼ T −1 ) and the viscosity (η ∼ T −2 ) at T T F , was confirmed by Anderson et al [41], Abel et al [42] and König and Pobell [43].…”

Section: Transport Properties At Very Low Temperaturessupporting

confidence: 56%

Weak³He Pairing in³He-He(II) Mixtures

et al. 2011

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In this paper a theoretical study of a possible phase transition in dilute 3 He-He(II) mixtures is presented using the Galitskii-Migdal-Feynman formalism. The effective scattering length is calculated from the GalitskiiMigdal-Feynman T -matrix, which is essentially the effective scattering amplitude dependent on the medium. It is found that at very low 3 He concentrations the s-wave effective scattering length for 3 He-He(II) varies discontinuously from positive to negative values at some critical concentration. This indicates a crossover from a regime with dimers to another with the Cooper pairs. The binding energy of the weakly-bound dimers 3 He2 is computed. The effective p-wave scattering lengths are calculated and compared to the effective s-wave scattering lengths at low and high concentrations. It is found that p-scattering has an important effect on the instability of these mixtures at concentrations x > 1%. Finally, the transport coefficients are computed and compared to the theoretical predictions of Fu and Pethick and the experimental results of König and Pobell.

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Section: Transport Properties At Very Low Temperaturessupporting

confidence: 56%

Weak³He Pairing in³He-He(II) Mixtures

et al. 2011

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“…It is expected to contribute significantly to the damping of spin currents in doped semiconductors [12]. The random collision events also lead to spin diffusion, the tendency for spin currents to flow such as to even out spatial gradients in the spin density, which has been studied in high-temperature superconductors [13] and in liquid 3 He- 4 He solutions [14,15]. Creating spin currents poses a major challenge in electronic systems where mobile spins are scattered by their environment and by each other.…”

mentioning

confidence: 99%

Universal spin transport in a strongly interacting Fermi gas

Sommer

Roati

et al. 2011

Nature

289

418

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Transport of fermions is central in many fields of physics. Electron transport runs modern technology, defining states of matter such as superconductors and insulators, and electron spin, rather than charge, is being explored as a new carrier of information [1]. Neutrino transport energizes supernova explosions following the collapse of a dying star [2], and hydrodynamic transport of the quark-gluon plasma governed the expansion of the early Universe [3]. However, our understanding of non-equilibrium dynamics in such strongly interacting fermionic matter is still limited. Ultracold gases of fermionic atoms realize a pristine model for such systems and can be studied in real time with the precision of atomic physics [4,5]. It has been established that even above the superfluid transition such gases flow as an almost perfect fluid with very low viscosity [3,6] when interactions are tuned to a scattering resonance. However, here we show that spin currents, as opposed to mass currents, are maximally damped, and that interactions can be strong enough to reverse spin currents, with opposite spin components reflecting off each other. We determine the spin drag coefficient, the spin diffusivity, and the spin susceptibility, as a function of temperature on resonance and show that they obey universal laws at high temperatures. At low temperatures, the spin diffusivity approaches a minimum value set by /m, the quantum limit of diffusion, where is the reduced Planck's constant and m the atomic mass. For repulsive interactions, our measurements appear to exclude a metastable ferromagnetic state [7][8][9].Understanding the transport of spin, as opposed to the transport of charge, is of high interest for the novel field of spintronics [1]. While charge currents are unaffected by electron-electron scattering due to momentum conservation, spin currents will intrinsically damp due to collisions between opposite spin electrons, as their relative momentum is not conserved. This phenomenon is known as spin drag [10,11]. It is expected to contribute significantly to the damping of spin currents in doped semiconductors [12]. The random collision events also lead to spin diffusion, the tendency for spin currents to flow such as to even out spatial gradients in the spin density, which has been studied in high-temperature superconductors [13] and in liquid 3 He-4 He solutions [14,15]. Creating spin currents poses a major challenge in electronic systems where mobile spins are scattered by their environment and by each other. However, in ultracold atoms we have the freedom to first prepare an essentially non-interacting spin mixture, separate atoms spatially via magnetic field gradients, and only then induce strong interactions. Past observations of spin currents in ultracold Fermi gases [16,17] were made in the weaklyinteracting regime. Here we access the regime near a Feshbach resonance [5], where interactions are as strong as allowed by quantum mechanics (the unitarity limit). We measure spin transport properties, the spin drag coeffici...

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“…The most appealing one is certainly the Bardeen-Cooper-Schrieffer (BCS) type superfluidity, since the presence of bosonfermion interaction in the mixture is expected to induce an effective attraction between fermions by exchanging density fluctuations of the bosonic background [5,6], analogously to that of superfluid 3 He and 4 He in lowtemperature physics [7,8]. With this respect, the recently reported quantum degenerate mixtures of 40 K (fermion) and 87 Rb (boson) by the LENS group would be particularly interesting due to the large boson-fermion attraction, which has been directly manifested by the collapse of the degenerate fermions above a critical number of particles [4], or alternatively, by the observation that the Bose-Einstein condensate (BEC) coexisting with the Fermi gas inverts its aspect ratio more rapidly than a pure condensate during the ballistic expansion [3].…”

Section: Introductionmentioning

confidence: 99%

Expansion of a quantum degenerate boson-fermion mixture

Liu

Modugno

2003

Phys. Rev. A

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We study the expansion of an ultracold boson-fermion mixture released from an elongated magnetic trap, in the context of a recent experiment at LENS (G. Roati et al., Phys. Rev. Lett. 89, 150403 (2002)). We discuss in some details the role of the boson-fermion interaction on the evolution of the radial-to-axial aspect ratio of the condensate, and show that it depends crucially on the relative dynamics of the condensate and degenerate Fermi gas in the radial direction, which is characterized by the ratio between the trapping frequency for fermions and for bosons. Our numerical simulations are in reasonable agreement with the experiment.

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Thermal and Magnetic Properties of Dilute Solutions ofHe3inHe4a

Cited by 170 publications

References 10 publications

Weak³He Pairing in³He-He(II) Mixtures

Weak³He Pairing in³He-He(II) Mixtures

Universal spin transport in a strongly interacting Fermi gas

Expansion of a quantum degenerate boson-fermion mixture

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Thermal and Magnetic Properties of Dilute Solutions ofHe3inHe4a

Cited by 170 publications

References 10 publications

Weak3He Pairing in3He-He(II) Mixtures

Weak3He Pairing in3He-He(II) Mixtures

Universal spin transport in a strongly interacting Fermi gas

Expansion of a quantum degenerate boson-fermion mixture

Contact Info

Product

Resources

About

Weak³He Pairing in³He-He(II) Mixtures

Weak³He Pairing in³He-He(II) Mixtures