Nucleation and phase separation in superfluid3He-4He solutions

Nucleation at quantized vortices and the heterogeneous phase separation in supersaturated superfluid 3He-4He liquid mixtures

“…To estimate the latter, it is necessary to know the effective density ρ eff (7) which proves to be approximately equal to ρ eff ≈ 2.2ρ s at the phase separation line and lies within the range 0.23 -0.40 g/cm 3 . The highest possible crossover temperature T q, max can be estimated either from (9) at p = 1 or from (10) at p = 0.5. This results in relatively small temperatures T T q, max 2.3 mK necessary for a possible observation of quantum nucleation.…”

“…The variation rate in the 3 He concentration is usually about 10 −4 % per second. The state of the liquid mixture is recorded by two methods [6][7][8][9][10]. The acoustic method is based on the sound velocity variation in the course of phase separation of liquid mixture and the capacitive one is based on the measurement of dielectric permittivity.…”

Critical macroscopic quantum effects in quantum nucleation

“…It was found that the measured value of ∆x 3,cr is almost independent of temperature below a temperature of the order of 10 mK and then increases with temperature. A sharp change at the crossover temperature was observed [16,17]. The experimental data of the critical deviation ∆x 3,cr of 3 He concentration distribute randomly into a band region with sharp edges having the value ∼ 0.0025 at the upper edge and ∼ 0.0017 at the lower edge in ref.…”

“…The nucleation of the pure 3 He phase from a supersaturated 3 He-4 He mixture of dilute gas was first discussed as a tunneling process in a capillarity model of Lifshitz [15] and coworkers. The first experimental study of the phase separation from supersaturated 3 He-4 He liquid mixtures was made by Satoh and coworkers [16] and subsequently by Chagovets et al [17]. The temperature dependence of the "critical" deviation of 3 He concentration ∆x 3,cr , which denotes the difference of the 3 He concentrations before and after the nucleation, was measured in experiments.…”

“…A much higher value of ∆x 3,cr is reported in ref. [17]. Although various efforts have been made, an explanation for the band structure has not been put forward so far [18].…”