Observation of Magnetic Flux Generated Spontaneously During a Rapid Quench of Superconducting Films

Abstract

We report observations of spontaneous formation of magnetic flux lines during a rapid quench of YBa(2)Cu(3)O(7-delta) films through T(c). This effect is predicted according to the Kibble-Zurek mechanism of creation of topological defects of the order parameter during a symmetry-breaking phase transition. Our previous experiment, at a quench rate of 20 K/s, gave null results. In the present experiment, the quench rate was increased to >10(8) K/s. The amount of spontaneous flux increases weakly with the cooling rate.

Effects of multiplicative noise in relativistic phase transitions

“…In condensed matter physics several experiments have been performed to check (2). Although the results are mixed the overall conclusion is positive [4,5,6,7,8].…”

“…We see our work here as a complementary study to the substantial analysis [11,12] that has been undertaken for the simpler and often less believable equation (5), to which it reduces for small η 2 and correspondingly weak noise. Finally, although we shall not pursue this here, we should not see (8) entirely in the context of QFT. There has been a considerable effort in condensed matter to examine multiplicative noise in systems with simple ηφ dissipation, but with ξφ multiplicative noise (η 2 = ξ 2 = 0) [27,28].…”

“…From the retarded nature of the Ks a more realistic, albeit still idealised, equation than (5) for the real relativistic scalar field φ is (8) where ξ 1 , ξ 2 are thermal noise.…”

Super-horizon cosmic string correlations

“…For example, the two-particle irreducible effective action formalism [34], which is a promising tool for perturbative non-equilibrium processes, fails to incorporate topological defects [35]. Interestingly, it is possible to test these effects experimentally in condensed matter systems which as superfluids and superconductors [36,37,38,39,40,41,42,43,44], which are, of course, fully quantum mechanical. So far, the emphasis has been on determining the number of strings, and the tests of spatial correlations have so far been limited to short-distance effects [15,45,46].…”

Design of magneto-optical system for imaging of magnetic flux created during a conductor–superconductor phase transition

“…To overcome this problem, one should use a physical system with strong pinning forces, which can prevent migration and mutual annihilation of the topological defects after the transition. Previous experiments on superconducting thin films detected a net flux consistent with the Kibble-Zurek prediction (Maniv et al 2003). There are as yet no measurements of the total vortex density or of the correlation function.…”