Thermal fluctuations of the Josephson current in a ring of superconducting grains

作     者：D. A. Garanin E. M. Chudnovsky 

作者机构：Physics Department Lehman College and Graduate School The City University of New York 250 Bedford Park Boulevard West Bronx New York 10468-1589 USA 

出 版 物：《Physical Review B》 (Phys. Rev. B)

年 卷 期：2017年第95卷第1期

页      面：014520-014520页

核心收录：

学科分类：07[理学] 0702[理学-物理学] 

基　　金：U.S. Department of Energy, USDOE Office of Science, SC 

主　　题：Josephson effect XY model 1-dimensional systems Tunnel junctions Metropolis algorithm Molecular dynamics 

摘      要：Thermal fluctuations of the Josephson current induced by the magnetic flux through a ring of N superconducting grains are studied. When a half-fluxon is threading the ring, I exhibits incoherent transitions between the two degenerate states due to thermal phase slips. We propose a numerical method to deal with both equilibrium and dynamic properties of Josephson systems. Computed transition rate has the form Γ=A(N)exp[−B(N)/T], where B(N) agrees with the analytical result derived for the energy barrier associated with phase slips. In the nondegenerate case (e.g., at a quarter-fluxon) the equilibrium value of I decreases with T due to harmonic excitations and then gets destroyed by phase slips.