13,649 research outputs found
Nonlocal Cooper pair Splitting in a pSn Junction
Perfect Cooper pair splitting is proposed, based on crossed Andreev
reflection (CAR) in a p-type semiconductor - superconductor - n-type
semiconductor (pSn) junction. The ideal splitting is caused by the energy
filtering that is enforced by the bandstructure of the electrodes. The pSn
junction is modeled by the Bogoliubov-de Gennes equations and an extension of
the Blonder-Tinkham-Klapwijk theory beyond the Andreev approximation. Despite a
large momentum mismatch, the CAR current is predicted to be large. The proposed
straightforward experimental design and the 100% degree of pureness of the
nonlocal current open the way to pSn structures as high quality sources of
entanglement
Interaction-induced Renormalization of Andreev Reflection
We analyze the charge transport between a one-dimensional weakly interacting
electron gas and a superconductor within the scaling approach in the basis of
scattering states. We derive the renormalization group equations, which fully
account for the intrinsic energy dependence due to Andreev reflection. A strong
renormalization of the corresponding reflection phase is predicted even for a
perfectly transparent metal-superconductor interface. The interaction-induced
suppression of the Andreev conductance is shown to be highly sensitive to the
normal state resistance, providing a possible explanation of experiments with
carbon-nanotube/superconductor junctions by Morpurgo et al. [Science 286, 263
(2001)].Comment: 4 pages, 2 figure
Quark scalar current correlator in AdS/QCD approach
We use a holographic model to compute the quark scalar current correlator.
Already used in other contexts, our model consists in a bulk field theory
defined on a deformed Anti de Sitter space and allows to derive analogous
results to those of the soft wall model. One issue of such computations is to
understand relevant holographic physical constraints which give predictive QCD
results rather than to make the inverse step as done until now.Comment: Talk presented at QCD 10, the 25-th anniversary of QCD Montpellier
conference series, to appear in the Proceeding
Absorption of heat into a superconductor-normal metal-superconductor junction from a fluctuating environment
We study a diffusive superconductor-normal metal-superconductor junction in
an environment with intrinsic incoherent fluctuations which couple to the
junction through an electromagnetic field. When the temperature of the junction
differs from that of the environment, this coupling leads to an energy transfer
between the two systems, taking the junction out of equilibrium. We describe
this effect in the linear response regime and show that the change in the
supercurrent induced by this coupling leads to qualitative changes in the
current-phase relation and for a certain range of parameters, an increase in
the critical current of the junction. Besides normal metals, similar effects
can be expected also in other conducting weak links.Comment: 5 pages, 4 figures - supplementary information included: 3 pages, 1
figure; minor modifications to the text and Fig. 2, added Ref. 1
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
Cold Quark Matter, Quadratic Corrections and Gauge/String Duality
We make an estimate of the quadratic correction in the pressure of cold quark
matter using gauge/string duality.Comment: 7 pages; v.2: reference added; v.3: reference and comments added,
version to appear in PRD; v4. final version to appear in PRD; v.5: key
reference adde
Crossed Andreev reflection in diffusive contacts
Crossed Andreev reflection in multiterminal structures in the diffusive
regime is addressed within the quasiclassical Keldysh-Usadel formalism. The
elastic cotunneling and crossed Andreev reflection of quasiparticles give
nonlocal currents and voltages (depending on the actual biasing of the devices)
by virtue of the induced proximity effect in the normal metal electrodes. The
magnitude of the nonlocal processes is found to scale with the square of the
barrier transparency and to decay exponentially with interface spacing.
Nonlocal cotunneling and crossed Andreev conductances are found to contribute
equally to the nonlocal current, which is of relevance to the use of normal
metal-superconducting heterostructures as sources of entanglement
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
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