4,399 research outputs found
Giant dispersion of critical currents in superconductor with fractal clusters of a normal phase
The influence of fractal clusters of a normal phase on the dynamics of a
magnetic flux trapped in a percolative superconductor is considered. The
critical current distribution and the current-voltage characteristics of
fractal superconducting structures in the resistive state are obtained for an
arbitrary fractal dimension of the cluster boundaries. The range of fractal
dimensions, where the dispersion of critical currents becomes infinite, is
found. It is revealed that the fractality of clusters depresses of the electric
field caused by the magnetic flux motion thus increasing the critical current
value. It is expected that the maximum current-carrying capability of a
superconductor can be achieved in the region of giant dispersion of critical
currents.Comment: 7 pages with 3 figure
Coherent Tunneling and Instantons in Presence of Classical Chaos
We consider the instanton approach to the problem of chaos assisted tunneling
in the context of existing analytical and numerical results obtained in this
field. We provide the estimation for the range of validity of this method and
briefly discuss possible applications of chaos assisted tunneling for quantum
computations
Deterministic Chaos in Quantum Field Theory
We discuss the necessity and demonstrate the validity of introduction the
notion of deterministic chaos in quantum field theory. Brief review of the
existing approaches to this problem is given. We compare proposed chaos
criterion for quantum fields with existing ones. Its consequences in particle
physics are also discussed
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