Quantum Nucleation of Phase Slips in 1-d Superfluids

Hans Peter Büchler, V. B. Geshkenbeǐn, G. Blatter

Ippei Danshita, Anatoli Polkovnikov

Ippei Danshita

Munehiro Nishida, Susumu Kurihara

The quantum nucleation of phase slips in neutral superfluids confined in a thin torus is investigated by means of the collective coordinate method. We have devised, with numerical justification, a certain collective coordinate to describe the quantum nucleation process of a phase slip. Considering the quantum fluctuation around the local minimum of the action, we calculate the effective mass of the phase slip. Due to the coherence of the condensate throughout the torus, the effective mass is proportional to the circumference L of the torus, and the decay rate has a strong exponential L-dependence. 03.75.Fi, 05.30.Jp, 64.60.Qb, 67.40.Fd, 67.40.Hf Typeset using REVTEX 1 The circulation of superflow in a macroscopic torus container is quantized. However, it has been pointed out that the quantized circulation can decay via the thermal nucleation of phase slips in the case of very narrow torus, or extremely thin superconducting wires [1–4]. If the temperature is low enough, it is probable that the nucleation due to the macroscopic

José A. Freire, Daniel P. Arovas, Herbert Levine

We use a 1D model of a superfluid based on the Gross-Pitaevskii Lagrangian to illustrate a general numerical method designed to find quantum tunneling rates in extended bosonic systems. Specifically, we study flow past an obstacle and directly solve the imaginary time dynamics to find the ``bounce'' solution connected with the decay of the metastable laminar state via phase slip nucleation. The action for the tunneling configuration goes to zero at the threshold (in superfluid velocity) for classical production of these slips. Applications to other processes are briefly discussed.

Subir Sachdev A, Matthias Vojta C