Flux bottlenecks in the mass superflux in solid helium

Ye. Vekhov, R. B. Hallock
2015 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Superfluid 4 He atoms are injected (withdrawn) asymmetrically into (from) a chamber filled with solid 4 He.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
more » ... 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[3] the community began to question the supersolid interpretation from several perspectives[4]. 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 [5] . 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 [6] [7] [8] [9] [10] [11] [12] . 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[13] through the solid, a so-called Luttinger-like behavior [14, 15] .
doi:10.1103/physrevb.91.180506 fatcat:mcp2ydimw5amnpw6lacy2v5by4