212,027 research outputs found
On parabolic Whittaker functions
We derive a Mellin-Barnes integral representation for solution to generalized
(parabolic) quantum Toda lattice introduced in \cite{GLO}, which presumably
describes the -equivariant Gromov-Witten invariants of
Grassmann variety.Comment: 14 page
Critical densities for the Skyrme type effective interactions
We use the stability conditions of the Landau parameters for the symmetric
nuclear matter and pure neutron matter to calculate the critical densities for
the Skyrme type effective nucleon-nucleon interactions. We find that the
critical density can be maximized by adjusting appropriately the values of the
enhancement factor associated with isovector giant dipole resonance,
the quantity which is directly related to the slope of the symmetry energy
and the Landau parameter . However, restricting , and
to vary within acceptable limits reduces the maximum value for the
critical density by . We also show that among the
various quantities characterizing the symmetric nuclear matter,
depends strongly on the isoscalar effective mass and
surface energy coefficient . For realistic values of and we
get to (fm).Comment: 10 pages, 3 figures. Physicsl Review C (in press
Correlation Assisted Phonon Softenings and the Mott-Peierls Transition in VO
To explore the driving mechanisms of the metal-insulator transition (MIT) and
the structural transition in VO2, we have investigated phonon dispersions of
rutile VO2 (R-VO2) in the DFT and the DFT+U (U : Coulomb correlation) band
calculations. We have found that the phonon softening instabilities occur in
both cases, but the softened phonon mode only in the DFT+U describes properly
both the MIT and the structural transition from R-VO2 to monoclinic VO2
(M1-VO2). This feature demonstrates that the Coulomb correlation effect plays
an essential role of assisting the Peierls transition in R-VO2. We have also
found from the phonon dispersion of M1-VO2 that M1 structure becomes unstable
under high pressure. We have predicted a new phase of VO2 at high pressure that
has a monoclinic CaCl2-type structure with metallic nature
Multivariate p-dic L-function
We construct multivariate p-adic L-function in the p-adic number fild by
using Washington method.Comment: 9 page
Type Ia supernova diversity: Standardizing the candles
Future use of type Ia supernovae for cosmology aims not only to determine the
equation of state of dark energy, but also to constrain possible variations in
its value. To achieve this goal, supernovae need to become better calibrated
standard candles - not only to improve the precision of the measurement, but
more importantly to gain better control over systematic uncertainties in order
to ensure the accuracy of the result.
Here we report on a project to quantify the diversity in type Ia supernovae,
and to look for trends and/or sub-types that can be used to improve their
calibration as standard candles. We implement a version of principal component
analysis on type Ia supernova spectra. Although the quantity of data is not
sufficient to draw any firm conclusions we show that this method holds promise
for, at the very least, effectively separating peculiar supernovae. Whether it
can be further used to improve the calibration of normal type Ia's remains a
project for future study.Comment: Conference Proceedings. Cefalu 2006, The multicoloured landscape of
compact objects and their explosive origins. Six pages, three figure
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