1,215 research outputs found
Josephson Effect in a Coulomb-blockaded SINIS Junction
The problem of Josephson current through Coulomb-blocked nanoscale
superconductor-normal-superconductor structure with tunnel contacts is
reconsidered. Two different contributions to the phase-biased supercurrent are
identified, which are dominant in the limits of weak and strong Coulomb
interaction. Full expression for the free energy valid at arbitrary Coulomb
strength is found. The current derived from this free energy interpolates
between known results for weak and strong Coulomb interaction as phase bias
changes from 0 to pi. In the broad range of Coulomb strength the current-phase
relation is substantially non-sinusoidal and qualitatively different from the
case of semi-ballistic SNS junctions. Coulomb interaction leads to appearance
of a local minimum in the current at some intermediate value of phase
difference applied to the junction.Comment: 5 pages, 2 EPS figures, JETP Letters style file include
Correlations of the local density of states in quasi-one-dimensional wires
We report a calculation of the correlation function of the local density of
states in a disordered quasi-one-dimensional wire in the unitary symmetry class
at a small energy difference. Using an expression from the supersymmetric
sigma-model, we obtain the full dependence of the two-point correlation
function on the distance between the points. In the limit of zero energy
difference, our calculation reproduces the statistics of a single localized
wave function. At logarithmically large distances of the order of the Mott
scale, we obtain a reentrant behavior similar to that in strictly
one-dimensional chains.Comment: Published version. Minor technical and notational improvements. 16
pages, 1 figur
Bistable and dynamic states of parametrically excited ultrasound in a fluid-filled cavity
In this paper we have considered the problem of parametric sound generation
in an acoustic resonator flled with a fluid, taking explicitely into account
the influence of the nonlinearly generated second harmonic. A simple model is
presented, and its stationary solutions obtained. The main feature of these
solutions is the appearance of bistable states of the fundamental field
resulting from the coupling to the second harmonic. An experimental setup was
designed to check the predictions of the theory. The results are consistent
with the predicted values for the mode amplitudes and parametric thresholds. At
higher driving values a self-modulation of the amplitudes is observed. We
identify this phenomenon with a secondary instability previously reported in
the frame of the theoretical model.Comment: 5 figures. Submitted to JAS
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