Observation of mass transport through solid 4He

Comment on "observation of unusual mass transport in solid hcp 4He".

Supersolidity and Superfluidity of Grain Boundaries

We have looked for dc mass transport through solid 4He in a simple experiment with two communicating vessels filled with solid 4He in equilibrium with liquid 4He. Through good quality crystals, we have observed no mass transport, in contradiction with the hypothesis of a Bose–Einstein condensation of vacancies. Through crystals containing grain boundaries, we have found superfluid flow along th...

Universal temperature dependence, flux extinction, and the role of 3He impurities in superfluid mass transport through solid 4He.

The mass flux, F, carried by as-grown solid (4)He in the range 25.6-26.3 bar rises with falling temperature, and at a concentration-dependent temperature, T(d), the flux decreases sharply within a few mK. We study F as a function of (3)He impurity concentration, χ. We find that T(d) is an increasing function of increasing χ. At temperatures above T(d) the flux has a universal temperature depend...

Mass flux and solid growth in solid 4He: 60 mK - 700 mK

Observation of unusual mass transport in solid hcp (4)He.

Solid (4)He has been created off the melting curve by growth at a nearly constant mass via the "blocked capillary" technique and growth from the (4)He superfluid at constant temperature. The experimental apparatus allows injection of (4)He atoms from superfluid directly into the solid. Evidence for the superfluidlike transport of mass through a sample cell filled with hcp solid (4)He off the me...