5,835 research outputs found
Nanopattern-stimulated superconductor-insulator transition in thin TiN films
We present the results of the comparative study of the influence of disorder
on transport properties in continuous and nanoperforated TiN films. We show
that nanopatterning turns a thin TiN film into an array of superconducting weak
links and stimulates both, the disorder- and magnetic field-driven
superconductor-to-insulator transitions, pushing them to lower degree of
disorder. We find that nanopatterning enhances the role of the two-dimensional
Coulomb interaction in the system transforming the originally insulating film
into a more pronounced insulator. We observe magnetoresistance oscillations
reflecting collective behaviour of the multiconnected nanopatterned
superconducting film in the wide range of temperatures and uncover the physical
mechanism of these oscillations as phase slips in superconducting weak link
network.Comment: 6 pages, 4 figure
M-Theory of Matrix Models
Small M-theories unify various models of a given family in the same way as
the M-theory unifies a variety of superstring models. We consider this idea in
application to the family of eigenvalue matrix models: their M-theory unifies
various branches of Hermitean matrix model (including Dijkgraaf-Vafa partition
functions) with Kontsevich tau-function. Moreover, the corresponding duality
relations look like direct analogues of instanton and meron decompositions,
familiar from Yang-Mills theory.Comment: 12 pages, contribution to the Proceedings of the Workshop "Classical
and Quantum Integrable Systems", Protvino, Russia, January, 200
Resolvents and Seiberg-Witten representation for Gaussian beta-ensemble
The exact free energy of matrix model always obeys the Seiberg-Witten (SW)
equations on a complex curve defined by singularities of the quasiclassical
resolvent. The role of SW differential is played by the exact one-point
resolvent. We show that these properties are preserved in generalization of
matrix models to beta-ensembles. However, since the integrability and
Harer-Zagier topological recursion are still unavailable for beta-ensembles, we
need to rely upon the ordinary AMM/EO recursion to evaluate the first terms of
the genus expansion. Consideration in this paper is restricted to the Gaussian
model.Comment: 15 page
Nonlocal stabilization of nonlinear beams in a self-focusing atomic vapor
We show that ballistic transport of optically excited atoms in an atomic
vapor provides a nonlocal nonlinearity which stabilizes the propagation of
vortex beams and higher order modes in the presence of a self-focusing
nonlinearity. Numerical experiments demonstrate stable propagation of lowest
and higher order vortices over a hundred diffraction lengths, before
dissipation leads to decay of these structures.Comment: 3 figure
- …