7,262 research outputs found
Estimation of the particle-antiparticle correlation effect for pion production in heavy ion collisions
Estimation of the back-to-back pi-pi correlations arising due to evolution of
the pionic field in the course of pion production process is given for central
heavy nucleus collisions at moderate energies.Comment: 6 LaTeX pages + 5 ps figure
Projected Three-Pion Correlation Functions
We propose a new procedure for constructing projected three-pion correlation
functions which reduces undesirable artificial momentum dependences resulting
from the commonly used procedure and facilitates comparison of three-pion
correlation data with theoretical models.Comment: 6 pages revtex, incl. 1 figure. Submitted as Brief Report to Physical
Review C. Normalization error and typos correcte
Local transport in a disorder-stabilized correlated insulating phase
We report the experimental realization of a correlated insulating phase in 2D
GaAs/AlGaAs heterostructures at low electron densities in a limited window of
background disorder. This has been achieved at mesoscopic length scales, where
the insulating phase is characterized by a universal hopping transport
mechanism. Transport in this regime is determined only by the average electron
separation, independent of the topology of background disorder. We have
discussed this observation in terms of a pinned electron solid ground state,
stabilized by mutual interplay of disorder and Coulomb interaction.Comment: 4+delta pages, 4 figures, To appear in the Physical Review B (Rapid
Comm
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
The influence of spin-dependent phases of tunneling electrons on the conductance of a point ferromagnet/isolator/d-wave superconductor contact
The influence of phase shifts of electron waves passing through and reflected
by the potential barrier on the Andreev reflection in a
ferromagnet/isolator/d-wave superconductor (FIS) contact is studied. It is
found that in a superconductor the surface spin-dependent Andreev bound states
inside the superconducting gap are formed as a result of the interference of
electron-like and hole-like quasiparticles due to repeated Andreev reflections.
The peak in the conductance of the FIS contact at the zero potential for the
(110)-oriented superconductor disappears rapidly as the polarization of a
ferromagnet increases, whereas for the (100)-oriented superconductor it
appears. The physical reason for this behavior of conductance is discussed.Comment: 8 pages, 4 figure
Josephson current through a Kondo molecule
We investigate transport of Cooper pairs through a double quantum dot (DQD)
in the Kondo regime and coupled to superconducting leads. Within the
non-perturbative slave boson mean-field theory we evaluate the Josephson
current for two different configurations, the DQD coupled in parallel and in
series to the leads. We find striking differences between these configurations
in the supercurrent as a function of the ratio t/\Gamma, where t is the
interdot coupling and \Gamma is the coupling to the leads: the critical current
I_c decreases monotonously with t/\Gamma for the parallel configuration whereas
I_c exhibits a maximum at t/\Gamma=1 in the serial case. These results
demonstrate that a variation of the ratio t/\Gamma enables to control the flow
of supercurrent through the Kondo resonance of the DQD.Comment: 5 pages, 4 figure
Andreev quantum dot with several conducting channels
We study an Andreev quantum dot, that is a quantum dot inserted in a
superconducting ring, with several levels or conducting channels. We analyze
the degeneracy of the ground state as a function of the phase difference and of
the gate voltage and find its dependence on the Coulomb interaction within and
between channels. We compute a (non integer) charge of the dot region and
Josephson current. The charge-to-phase and current-to-gate voltage
sensitivities are studied. We find that, even in the presence of Coulomb
interaction between the channels, the sensitivity increases with the number of
channels, although it does not scale linearly as in the case with no
interactions. The Andreev quantum dot may therefore be used as a sensitive
detector of magnetic flux or as a Josephson transistor.Comment: 13 pages, 10 figures, minor correction
A quantum hydrodynamics approach to the formation of new types of waves in polarized two-dimension systems of charged and neutral particles
In this paper we explicate a method of quantum hydrodynamics (QHD) for the
study of the quantum evolution of a system of polarized particles. Though we
focused primarily on the two-dimension physical systems, the method is valid
for three-dimension and one-dimension systems too. The presented method is
based upon the Schr\"{o}dinger equation. Fundamental QHD equations for charged
and neutral particles were derived from the many-particle microscopic
Schr\"{o}dinger equation. The fact that particles possess the electric dipole
moment (EDM) was taken into account. The explicated QHD approach was used to
study dispersion characteristics of various physical systems. We analyzed
dispersion of waves in a two-dimension (2D) ion and hole gas placed into an
external electric field which is orthogonal to the gas plane. Elementary
excitations in a system of neutral polarized particles were studied for 1D, 2D
and 3D cases. The polarization dynamics in systems of both neutral and charged
particles is shown to cause formation of a new type of waves as well as changes
in the dispersion characteristics of already known waves. We also analyzed wave
dispersion in 2D exciton systems, in 2D electron-ion plasma and 2D
electron-hole plasma. Generation of waves in 3D system neutral particles with
EDM by means of the beam of electrons and neutral polarized particles is
investigated.Comment: 15 pages, 7 figure
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