10,212 research outputs found
Two-photon correlations as a sign of sharp transition in quark-gluon plasma
The photon production arising due to time variation of the medium has been
considered. The Hamilton formalism for photons in time-variable medium (plasma)
has been developed with application to inclusive photon production. The results
have been used for calculation of the photon production in the course of
transition from quark-gluon phase to hadronic phase in relativistic heavy ion
collisions. The relative strength of the effect as well as specific two- photon
correlations have been evaluated. It has been demonstrated that the opposite
side two-photon correlations are indicative of the sharp transition from the
quark-gluon phase to hadrons.Comment: 23 pages, 2 figure
Hydrodynamic description of transport in strongly correlated electron systems
We develop a hydrodynamic description of the resistivity and
magnetoresistance of an electron liquid in a smooth disorder potential. This
approach is valid when the electron-electron scattering length is sufficiently
short. In a broad range of temperatures, the dissipation is dominated by heat
fluxes in the electron fluid, and the resistivity is inversely proportional to
the thermal conductivity, . This is in striking contrast with the
Stokes flow, in which the resistance is independent of and
proportional to the fluid viscosity. We also identify a new hydrodynamic
mechanism of spin magnetoresistance
Microwave stabilization of edge transport and zero-resistance states
Edge channels play a crucial role for electron transport in two dimensional
electron gas under magnetic field. It is usually thought that ballistic
transport along edges occurs only in the quantum regime with low filling
factors. We show that a microwave field can stabilize edge trajectories even in
the semiclassical regime leading to a vanishing longitudinal resistance. This
mechanism gives a clear physical interpretation for observed zero-resistance
states
Nonlocal Andreev reflection at high transmissions
We analyze non-local effects in electron transport across three-terminal
normal-superconducting-normal (NSN) structures. Subgap electrons entering
S-electrode from one N-metal may form Cooper pairs with their counterparts
penetrating from another N-metal. This phenomenon of crossed Andreev reflection
-- combined with normal scattering at SN interfaces -- yields two different
contributions to non-local conductance which we evaluate non-perturbatively at
arbitrary interface transmissions. Both these contributions reach their maximum
values at fully transmitting interfaces and demonstrate interesting features
which can be tested in future experiments.Comment: 4 pages, 4 figure
Re-entrant localization of single particle transport in disordered Andreev wires
We study effects of disorder on the low energy single particle transport in a
normal wire surrounded by a superconductor. We show that the heat conductance
includes the Andreev diffusion decreasing with increase in the mean free path
and the diffusive drift produced by a small particle-hole asymmetry,
which increases with increasing . The conductance thus has a minimum as a
function of which leads to a peculiar re-entrant localization as a
function of the mean free path.Comment: 4 pages, 2 figure
Frobenius-Perron Resonances for Maps with a Mixed Phase Space
Resonances of the time evolution (Frobenius-Perron) operator P for phase
space densities have recently been shown to play a key role for the
interrelations of classical, semiclassical and quantum dynamics. Efficient
methods to determine resonances are thus in demand, in particular for
Hamiltonian systems displaying a mix of chaotic and regular behavior. We
present a powerful method based on truncating P to a finite matrix which not
only allows to identify resonances but also the associated phase space
structures. It is demonstrated to work well for a prototypical dynamical
system.Comment: 5 pages, 2 figures, 2nd version as published (minor changes
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