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Superconductor-insulator quantum phase transition in a single Josephson junction

Carlos P. Herrero·Andrei D. Zaikin
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Abstract

The superconductor-to-insulator quantum phase transition in resistively shunted Josephson junctions is investigated by means of path-integral Monte Carlo simulations. This numerical technique allows us to directly access the (previously unexplored) regime of the Josephson-to-charging energy ratios E_J/E_C of order one. Our results unambiguously support an earlier theoretical conjecture, based on renormalization-group calculations, that at T -> 0 the dissipative phase transition occurs at a universal value of the shunt resistance R_S = h/4e^2 for all values E_J/E_C. On the other hand, finite-temperature effects are shown to turn this phase transition into a crossover, which position depends significantly on E_J/E_C, as well as on the dissipation strength and on temperature. The latter effect needs to be taken into account in order to reconcile earlier theoretical predictions with recent experimental results.

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Carlos P. Herrero, Andrei D. Zaikin. 2001-10-01. Superconductor-insulator quantum phase transition in a single Josephson junction. https://doi.org/10.1103/physrevb.65.104516

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