2011/07/21 by S. T. Chui, Chui, S. T.
Physics and Astronomy · #Cold Atom Physics and Bose-Einstein Condensates #FOS: Physical sciences #Other Condensed Matter (cond-mat.other) #Physics of Superconductivity and Magnetism #Quantum Physics (quant-ph) #Quantum, superfluid, helium dynamics #cond-mat.other #quant-ph
paper · pdf · doi:10.48550/arxiv.1107.4298
arxiv created 2011/07/21 · openalex publication_date 2011/07/21 · arxiv updated 2011/07/22 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We apply our recently developed model of a Bose condensate of quantum kink wave in solid He4 to understand recent torsional oscillator experimental results of the citical velocities and the effect of the steady and oscillating rotations at around 0.1 degree K. When the D.C. rotation is present we find a decrease of the Q factor given by Q-1 ∝ fsf× ΩD/ωTO where fsf is the superfluid fraction; ΩD, the D. C. angular rotation velocity, ωTO, the torsional oscillator oscillating frequency. We estimate the AC critical velocity ΩAcrit as that required to generate a kink wave of wavevector 2π/Ld where Ld is the distance between nodes of the dislocation network. We generalize this to include a steady rotation and find a D. C. critical velocity ΩDcrit ∝ (ΩAcrit)1/2. Estimates for both the steady and the oscillating critical velocities are in order of magnitude agreement with experimental results. We have also examined an alternative mechanism of kink tunnelling through a node in the dislocation networm and find that there is also a dependence on the torsional oscillator frequency: ΩDcrit=[ΩAcrit ωTO2π]1/2. The DC critical velocity ΩDcrit is ten times higher than the experimental value.