Thermal conductivity of superfluid 3He in aerogel

Abstract

We report theoretical calculations of the thermal conductivity of superfluid 3 He impregnated into high-porosity aerogel and compare these results with available experimental data.

Impurity Effects of Aerogel in Superfluid3He

“…The non-zero spectral weight at the Fermi energy is attributed to overlapping bound states. This behavior is a direct indication of gapless superfluidity and has been observed and predicted for the thermal conductivity, 56,74) magnetic susceptibility, 57,61) and attenuation of sound. contrast to what has been found by most groups to be characteristic of the B-phase.…”

“…17, showing that there is a weak anomaly at the transition temperature. Behavior in the normal fluid and in the superfluid phases has been analyzed by Sharma and Sauls 56) from which ¼ 205 nm was determined, somewhat larger than the trend from other experiments. It is possible that the thermal boundary resistance between the aerogel and pure 3 He superfluids might play a significant role.…”

“…Theoretical interpretation of experiments are mostly based on this model or its variations. 30,39,[50][51][52][53][54][55][56][57] The modified -parameters, a i for the case of superfluid 3 He in aerogel can be expressed as, …”

“…Calculations have been performed by Sharma and Sauls 56) and Mineev and Krotkov 57) for which a representative example of data is shown in Fig. 18 from Barker et al 61) A value of ¼ 140 nm fits the data best and the distinction between HISM and IISM is not discernible.…”

Microscopic theory of sound propagation in the superfluidHe3–aerogel system

“…[1][2][3] When the aerogel is immersed in liquid 3 He, it provides a random distribution of short-range potentials. Since an early observation 1 of superfluidity of 3 He in aerogel, a number of theoretical works to understand the impurity effect of aerogel in liquid 3 He have been reported concerning the transition temperature, 3-6 the superfluid density, 3-6 spin susceptibility, 7,8 phase diagram, 9,10 thermal conductivity, 11 acoustics, 4,12-15 and possible order-parameter symmetry. 16 Here we report a theoretical study on the acoustics of the superfluid 3 He-aerogel system.…”