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Quantum tunneling of semifluxons

E. Goldobin·K. Vogel·O. Crasser·R. Walser·W. P. Schleich·D. Koelle·R. Kleiner
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Abstract

We consider a system of two semifluxons of opposite polarity in a 0-pi-0 long Josephson junction, which classically can be in one of two degenerate states: up-down or down-up. When the distance $a$ between the 0-pi boundaries (semifluxon's centers) is a bit larger than the crossover distance $a_c$, the system can switch from one state to the other due to thermal fluctuations or quantum tunneling. We map this problem to the dynamics of a single particle in a double well potential and estimate parameters for which quantum effects emerge. We also determine the classical-to-quantum crossover temperature as well as the tunneling rate (energy level splitting) between the states up-down and down-up.

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E. Goldobin, K. Vogel, O. Crasser, R. Walser, W. P. Schleich, D. Koelle, R. Kleiner. 2005-04-20. Quantum tunneling of semifluxons. https://doi.org/10.1103/physrevb.72.054527

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