Computer simulations of quantum phase slippage in superfluid 3He

Abstract

Quantum-dynamic processes of phase slippage in3He are demonstrated to be associated with superfluid vortex nucleation, thus confirming Anderson's scenario for phase slippage through vortex generation and motion in superfluids. We also encounter more complex phase-slip processes, involving phase-slip centers (PSC), phase-slip lines (PSL), and various combinations thereof (PSC + PSL, PSC + PSC, etc.) for the coupled multi-component order-parameter amplitudes. The total order parameter does not vanish - phase slippage in superfluid 3He is inherently a nonlocal process in space-time. Time-dependent Ginzburg-Landau (TDGL) theory is used to compute the current-phase relation for superfluid 3He flow driven by a chemical-potential difference; this serves to provide results that are useful to the experimentalists for an interpretation of their data. Our simulations reveal a tendency for avalanches of vortices to appear simultaneously in long channels, during the period of a single Josephson oscillation. We also simulate dynamics of vortex interactions, such as vortex recombination and an intrinsic “vortex mill”, in which a vortex bifurcates into two vortices of the same circulation plus one of the opposite circulation.