QFS2016 Book of Abstracts

Abstracts

T3 “Pure” superfluid 3 He, an introduction. George Pickett Lancaster University, UK

At millikelvin temperatures the Fermionic 3 He atoms in liquid couple to form Cooper pairs to create superfluid 3 He. The Cooper pair has an angular moment of ~ , in which the two component atoms orbit each other as a loosely-connected dimer. Since the angular momentum is odd, to preserve parity, the spin must also be odd, i.e. also ~ . This gives the Cooper pairs a very rich structure allowing the existence of several phases with very different properties and provides a number of handles for probing the condensate especially by NMR and quasiparticle “optics”. An interesting regime is the very low temperature region, where the condensate is essentially “pure” giving rise to a number of interesting properties and with a wavefunction whose symmetry provides an interesting simulation of the metric of the universe, allowing “tabletop” cosmological experiments.

T4 The Supersolid Story Moses Chan Penn State University, USA

Torsional oscillator (TO) measurements of solid 4 He carried out twelve years ago found an abrupt drop in the resonant period (∆P) below 0.2K, suggesting superfluid onset in the solid. However, subsequent studies indicate the ∆P is due to the stiffening of the solid. New TO studies free of stiffening effect placed an upper limit of superfluidity in solid of 5 × 10 − 6 . Interestingly this is not the last word in supersolidity. By means of a clever design, Hallock found evidence of superfluid-like mass flow through solid 4 He sandwiched between two superfluid reservoirs. Recent experiments at UMass, Alberta and Penn State on the nature of this mass flow will be discussed

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