Flux bottlenecks in the mass superflux in solid helium
Physical Review B
Superfluid 4 He atoms are injected (withdrawn) asymmetrically into (from) a chamber filled with solid 4 He. Two in situ capacitance pressure gauges are located at the ends of the solid helium sample at different distances from where the superfluid meets the solid 4 He. The pressure change kinetics are slower at the more distant gauge. This demonstrates the presence of a mass flux bottleneck inside the solid helium sample. The temperature dependence of the maximum flux reveals a crossover and
... a crossover and this is discussed in the context of phase slips on quasi-1-D pathways. PACS numbers: 67.80.-s, 67.80.B-, 67.80.Bd, 71.10.Pm The Physics community was greatly stimulated by the possibility of supersolidity suggested by the torsional oscillator experiments of Kim and Chan[1, 2]; many groups reported corroborating evidence. But, with the realization that previously unexpected shear modulus behavior was present in the solid the community began to question the supersolid interpretation from several perspectives. More recent work has shown that these mechanical effects clearly were dominant and it is now believed that there is little, if any, evidence for a supersolid available from torsional oscillator experiments  . In conceptually different work, studies of the flux of 4 He that passes through a sample cell filled with solid helium have been carried out        . These experiments revealed the dependence of the flux rate on the solid helium temperature, the applied chemical potential difference, ∆µ, and the 3 He impurity concentration. They also revealed a dramatic reduction of the flux at a 3 He concentrationdependent temperature, T d , a universal temperature dependence above T d and no flux above T h ≈ 630 mK, etc. Some of the UMass data [10, 11] were interpreted to be consistent with one-dimensional conductivity through the solid, a so-called Luttinger-like behavior [14, 15] .