10,159 research outputs found
Stimulated Raman backscattering of laser radiation in deep plasma channels
Stimulated Raman backscattering (RBS) of intense laser radiation confined by
a single-mode plasma channel with a radial variation of plasma frequency
greater than a homogeneous-plasma RBS bandwidth is characterized by a strong
transverse localization of resonantly-driven electron plasma waves (EPW). The
EPW localization reduces the peak growth rate of RBS and increases the
amplification bandwidth. The continuum of non-bound modes of backscattered
radiation shrinks the transverse field profile in a channel and increases the
RBS growth rate. Solution of the initial-value problem shows that an
electromagnetic pulse amplified by the RBS in the single-mode deep plasma
channel has a group velocity higher than in the case of homogeneous-plasma
Raman amplification. Implications to the design of an RBS pulse compressor in a
plasma channel are discussed.Comment: 11 pages, 3 figures; submitted to Physics of Plasma
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
Thermal rectification of electrons in hybrid normal metal-superconductor nanojunctions
We theoretically investigate heat transport in hybrid normal
metal-superconductor (NS) nanojunctions focusing on the effect of thermal
rectification. We show that the heat diode effect in the junction strongly
depends on the transmissivity and the nature of the NS contact. Thermal
rectification efficiency can reach up to 123% for a fully-transmissive
ballistic junction and up to 84% in diffusive NS contacts. Both values exceed
the rectification efficiency of a NIS tunnel junction (I stands for an
insulator) by a factor close to 5 and 3, respectively. Furthermore, we show
that for NS point-contacts with low transmissivity, inversion of the heat diode
effect can take place. Our results could prove useful for tailoring heat
management at the nanoscale, and for mastering thermal flux propagation in
low-temperature caloritronic nanocircuitry.Comment: 4+ pages, 3 color figure
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
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