Supersolid 4He under DC rotation: Energy dissipation for slow and fast temperature sweeps

In this report, we describe torsional oscillator (TO) measurements under DC rotation of a 49 bar 4He-sample, at Vac = 0.2 mm/s. We investigated the behavior of the energy dissipation (~ ΔQ-1) as well as the supersolid fraction for different rotation velocities (0 < Ω < 1.256 rad/s) and Vac = 0.06, 0.2 mm/s in the temperature range of from 47 mK to 150 mK, using fast (~3h) and slow (~ 55h) temperature sweeps. Variation of Ω did not influence the supersolid fraction. The performed analyzes have shown a linear increase of the ΔQ-1 vs. Ω for high Vac = 0.2 mm/s (for fast and slow temperature sweeps). In the case of Vac = 0.06 mm/s, no change of the energy dissipation was observed up to Ω = 0.628 rad/s for the low temperature limit. These results suggest a possible explanation for the energy dissipation in supersolid 4He and its proportionality to the number of low dimensional vortices influenced by torsional oscillations. The 3D-vortex lines created by DC rotation can dissipate their energy by interaction with low dimensional vortices. Their dynamics under rotation are characterized by long relaxation times.