2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/27871We study a Josephson junction ladder in a magnetic field in the absence of charging effects via a transfer matrix formalism. The eigenvalues of the transfer matrix are found numerically, giving a determination of the different phases of the ladder. The spatial periodicity of the ground state exhibits a devil's staircase as a function of the magnetic flux filling factor f. If the transverse Josephson coupling is varied a continuous superconducting-normal transition in the transverse direction is observed, analogous to the breakdown of the KAM trajectories in dynamical systems. We also examine how these properties may be affected by a current injected along the ladder.22 pages, 10 eps figures, REVTEX, better version of Fig. 9 (3 Mb) available from colin@thphys.ox.ac.ukStatistical MechanicsSuperconductivitytext