2010/02/12 by Oleksandr Syshchenko James Day John Beamish, Beamish, Oleksandr Syshchenko James Day John
Physics and Astronomy · #FOS: Physical sciences #Other Condensed Matter (cond-mat.other) #cond-mat.other
paper · pdf · doi:10.48550/arxiv.1002.2608
arxiv created 2010/04/13 · arxiv updated 2010/04/15
Torsional oscillator experiments on solid 4He show frequency changes which suggest mass decoupling, but the onset is broad and is accompanied by a dissipation peak. We have measured the elastic shear modulus over a broad frequency range, from 0.5 Hz to 8 kHz, and observe similar behavior - stiffening and a dissipation peak. These features are associated with a dynamical crossover in a thermally activated relaxation process in a disordered system rather than a true phase transition. If there is a transition in the DC response, e.g. to a supersolid state, it must occur below 55 mK.