Producing and imaging quantum turbulence via pair-breaking in superfluid He3−B

Noble, M. T. and Ahlstrom, S. L. and Bradley, D. I. and Guise, E. A. and Haley, R. P. and Kafanov, S. and Pickett, G. R. and Poole, M. and Schanen, R. and Wilcox, T. and Woods, A. J. and Zmeev, D. E. and Tsepelin, V. (2022) Producing and imaging quantum turbulence via pair-breaking in superfluid He3−B. Physical Review B, 105 (17): 174515. ISSN 2469-9950

Abstract

Destroying superfluidity is a fundamental process and in fermionic superfluid such as 3 He − it splits Cooper pairs into thermal excitations, quasiparticles. At the lowest temperatures, a gas of these quasiparticle excitations is tenuous enough for the propagation to be ballistic. We describe here an exploitation of the ballistic quasiparticles as the “photons” to observe the local destruction of superfluid 3 He − by a mechanical resonator. We use a 5 by 5 pixel quasiparticle camera to image an emergence of quasiparticle excitations and a tangle of quantized vortices accompanying the pair-breaking. The detected quantum tangle is asymmetric around the mechanical resonator and is governed by the stability of vortices on the resonator surface. The vortex distribution shows that a conventional production of a quantum tangle via repetitive emission of vortex rings starts on the top surface of the generator and spreads around whole surface at high velocity when escaping vortex rings get retrapped by the moving resonator.