1,601,548 research outputs found
Raman Scattering in Cuprate Superconductors
A theory for electronic Raman scattering in the cuprate superconductors is
presented with a specific emphasis on the polarization dependence of the
spectra which can infer the symmetry of the energy gap. Signatures of the
effects of disorder on the low frequency and low temperature behavior of the
Raman spectra for different symmetry channels provide detailed information
about the magnitude and the phase of the energy gap. Properties of the theory
for finite T are discussed and compared to recent data concerning the doping
dependence of the Raman spectra in cuprate superconductors, and remaining
questions are addressed.Comment: 27 pages, 11 figures, style file include
Resolving the molecular gas around the lensed quasar RXJ0911.4+0551
We report on high angular resolution observations of the CO(7-6) line and
millimeter continuum in the host galaxy of the gravitationally lensed (z~2.8)
quasar RXJ0911.4+0551 using the Plateau de Bure Interferometer. Our CO
observations resolve the molecular disk of the source. Using a lens model based
on HST observations we fit source models to the observed visibilities. We
estimate a molecular disk radius of 10.2 kpc and an inclination of
696\deg, the continuum is more compact and is only marginally resolved by
our observations. The relatively low molecular gas mass, Msolar, and far infrared luminosity, Lsolar, of this quasar could be explained by its relatively low
dynamical mass, Msolar. It would be a
scaled-down version the QSOs usually found at high-z. The FIR and CO
luminosities lie on the correlation found for QSOs from low to high redshifts
and the gas-to-dust ratio () is similar to the one measured in the
z=6.4 QSO, SDSS J1148+5251. Differential magnification affects the
continuum-to-line luminosity ratio, the line profile and possibly the spectral
energy distribution.Comment: Accepted for publication in A&A, revised after language editin
Isovector Channel Role of Relativistic Mean Field Models in the Neutrino Mean Free Path
An improvement in the treatment of the isovector channel of relativistic mean
field (RMF) models based on effective field theory (E-RMF) is suggested, by
adding an isovector scalar (delta) meson and using a similar procedure to the
one used by Horowitz and Piekarewicz to adjust the isovector-vector channel in
order to achieve a softer density dependent symmetry energy of the nuclear
matter at high density. Their effects on the equation of state (EOS) at high
density and on the neutrino mean free path (NMFP) in neutron stars are
discussed.Comment: 20 pages, 8 figure
Two-boson Correlations in Various One-dimensional Traps
A one-dimensional system of two trapped bosons which interact through a
contact potential is studied using the optimized configuration interaction
method. The rapid convergence of the method is demonstrated for trapping
potentials of convex and non-convex shapes. The energy spectra, as well as
natural orbitals and their occupation numbers are determined in function of the
inter-boson interaction strength. Entanglement characteristics are discussed in
dependence on the shape of the confining potential.Comment: 5 pages, 3 figure
CPA for charge ordering in the extended Hubbard model
We study charge ordering in the extended Hubbard model with both on-site and
nearest neighbor Coulomb repulsion (U and V, respectively) within the Coherent
potential approximation (CPA). The phase boundary between the homogeneous and
charge ordered phase for the square lattice is obtained for different values of
U. It is shown that at quarter filling for all values of U the charge ordering
exists only if the inter-site Coulomb repulsion V exceeds certain critical
value which is of the order of the kinetic energy t. At finite temperature a
reentrant transition is found in some region of V.Comment: 5 pages, 4 figure
Dual frequency VSOP imaging of the jet in S5 0836+710
The luminous high-redshift (z=2.17) quasar S50836+710 has been observed in
October 1997 with the VSOP at 1.6 GHz and 5 GHz. We report here a previously
unpublished image made from the data at 1.6 GHz and compare the structure of a
relativistic jet in this quasazr at the two frequencies. We present a spectral
index image tracing spectral properties of the jet up to ~40 milliarcsecond
distance from the nucleus. The curved jet ridge line observed in the images and
the spectral index distribution can be described by Kelvin-Helmholtz
instability developing in a relativistic outflow with a Mach number of ~6. In
this description, the overall ridge line of the jet is formed by the helical
surface mode of Kelvin-Helmholtz instability, while areas of flatter spectral
index embedded into the flow correspond to pressure enhancements produced by
the elliptical surface mode of the instability. An alternative explanation
involving a sequence of slowly dissipating shocks cannot be ruled out at this
point.Comment: 7 pages, 4 figures, pasj00.cls. Submitted to PASJ. (Corrected figure
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