6 research outputs found
Spontaneous breakdown of the time reversal symmetry
The role of the environment initial conditions in the breaking of the time
reversal symmetry of effective theories and in generating the soft
irreversibility is studied by the help of Closed Time Path formalism. The
initial conditions break the time reversal symmetry of the solution of the
equation of motion in a trivial manner. When open systems are considered then
the initial conditions of the environment must be included in the effective
dynamics. This is achieved by means of a generalized -prescription
where the non-uniform convergence of the limit leaves behind a
spontaneous breakdown of the time reversal symmetry.Comment: Final version, to appear in Symmetr
Reversibility, coarse graining and the chaoticity principle
We describe a way of interpreting the chaotic principle of (ref. [GC1]) more
extensively than it was meant in the original works. Mathematically the
analysis is based on the dynamical notions of Axiom A and Axiom B and on the
notion of Axiom C, that we introduce arguing that it is suggested by the
results of an experiment (ref. [BGG]) on chaotic motions. Physically we
interpret a breakdown of the Anosov property of a time reversible attractor
(replaced, as a control parameter changes, by an Axiom A property) as a
spontaneous breakdown of the time reversal symmetry: the relation between time
reversal and the symmetry that remains after the breakdown is analogous to the
breakdown of -invariance while still holds.Comment: 15 pages, plain TeX, no figure
Properties of dirty two-bands superconductors with repulsive interband interaction: normal modes, length scales, vortices and magnetic response
Disorder in two-band superconductors with repulsive interband interaction
induces a frustrated competition between the phase-locking preferences of the
various potential and kinetic terms. This frustrated interaction can result in
the formation of an superconducting state, that breaks the time-reversal
symmetry. In this paper we study the normal modes and their associated
coherence lengths in such materials. We especially focus on the consequences of
the soft modes stemming from the frustration and time-reversal-symmetry
breakdown. We find that two-bands superconductors with such impurity-induced
frustrated interactions display a rich spectrum of physical properties that are
absent in their clean counterparts. It features a mixing of Leggett's and
Anderson-Higgs modes, and a soft mode with diverging coherence length at the
impurity-induced second order phase transition from states to
the state. Such a soft mode generically results in long-range attractive
intervortex forces that can trigger the formation of vortex clusters. We find
that, if such clusters are formed, their size and internal flux density have a
characteristic temperature dependence that could be probed in
muon-spin-rotation experiments. We also comment on the appearance of
spontaneous magnetic fields due to spatially varying impurities.Comment: Added discussion of spontaneous magnetic fields due to spatially
varying impurities; Replaced with a version in print in Phys. Rev. B; 17
pages, 8 figure