12,136 research outputs found
Some Multi-Quark Potentials, Pseudo-Potentials and AdS/QCD
The static three-quark potential and pseudo-potential of a pure SU(3) gauge
theory are studied in a five-dimensional framework known as AdS/QCD. The
results support the Y-ansatz for the baryonic area law. A comparison with the
quark-antiquark calculations shows the universality of the string tension as
well as the spatial string tension. We also discuss extensions to SU(N) gauge
theories.Comment: 18 pages, 7 figures; v2: a few sentences added and typos correcte
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
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
Normal state diamagnetism of charged bosons in cuprate superconductors
Normal state orbital diamagnetism of charged bosons quantitatively accounts
for recent high-resolution magnetometery results near and above the resistive
critical temperature Tc of superconducting cuprates. Our parameter-free
descriptions of normal state diamagnetism, Tc, upper critical fields and
specific heat anomalies unambiguously support the 3D Bose-Einstein condensation
at Tc of preformed real-space pairs with zero off-diagonal order parameter
above Tc, at variance with phase fluctuation (or vortex) scenarios of the
"normal" state of cuprates.Comment: 10 pages, 4 figure
Separated spin-up and spin-down evolution of degenerated electrons in two dimensional systems: Dispersion of longitudinal collective excitations in plane and nanotube geometry
Applying the separated spin evolution quantum hydrodynamics to
two-dimensional electron gas in plane samples and nanotubes located in external
magnetic fields we find new kind of wave in electron gas, which is called the
spin-electron acoustic wave. Separate spin-up electrons and spin-down electrons
evolution reveals in replacement of the Langmuir wave by the couple of hybrid
waves. One of two hybrid waves is the modified Langmuir wave. Another hybrid
wave is the spin-electron acoustic wave. We study dispersion of these waves in
two dimensional structures of electrons. We also consider dependence of
dispersion properties on spin polarisation of electrons in external magnetic
field.Comment: 5 pages, 5 figure
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