Nonequilibrium effects in the thermal switching of underdamped Josephson junctions

Abstract

We study the thermal escape problem in the low damping limit. We find that finiteness of the barrier is crucial for explaining the thermal activation results. In this regime, low barrier nonequilibrium corrections to the usual theories become necessary. We propose a simple theoretical extension accounting for these nonequilibrium processes which agrees numerical results. We apply our theory to the understanding of switching current curves in underdamped Josephson junctions.

Unzipping of DNA under the influence of external fields

“…However, in these ranges of the force, expression 6 is unphysical. One expects to have reliable results for barriers E/k B T > 3 [31].…”

Thermal activation at moderate-to-high and high damping: Finite barrier effects and force spectroscopy

“…The figure also shows the theoretical results studied in Ref. 5 and here. We see that the combination of the Drozdov-Hayashi 6 result for moderate-to-low damping values and our extension of the mean first passage time result for moderate-to-high ones, give a fairly good approximation to the numerically computed result for all damping of the system.…”

Stochastic first passage time accelerated with CUDA

“…The quantum behavior of JJ makes them a good candidate for the realization of a quantum bit; however, the quantum regime is only observed after the ordinary thermal activated regime has been tamed [33]. Thus, it is of interest to have precise numerical simulations of the thermal regime, simulations that are deeply connected with the theoretical predictions (and corrections) of Kramers' formula in the underdamped regime [3].…”

“…Kramers' rate theory [2,3]). From the experimental point of view, in Josephson Junctions (JJ) superconducting devices [4] the measurement of the threshold for the escapes is the only possibility (or the simplest way) to gain information on the internal dynamics of systems as quantum devices [5,6], threshold detectors [7][8][9] and arrays of JJ [10,11] of great interest for high frequency, up to the THz region, local oscillators [12].…”