21,065 research outputs found
Thermal QRPA with Skyrme interactions and supernova neutral-current neutrino-nucleus reactions
The Thermal Quasiparticle Random-Phase Approximation is combined with the
Skyrme energy density functional method (Skyrme-TQRPA) to study the response of
a hot nucleus to an external perturbation. For the sample nuclei, Fe and
Ge, the Skyrme-TQRPA is applied to analyze thermal effects on the
strength function of charge-neutral Gamow-Teller transitions which dominate
neutrino-nucleus reactions at ~MeV. For the relevant
supernova temperatures we calculate the cross sections for inelastic neutrino
scattering. We also apply the method to examine the rate of
neutrino-antineutrino pair emission by hot nuclei. The cross sections and rates
are compared with those obtained earlier from the TQRPA calculations based on
the phenomenological Quasiparticle-Phonon Model Hamiltonian. For inelastic
neutrino scattering on Fe we also compare the Skyrme-TQRPA results to
those obtained earlier from a hybrid approach that combines shell-model and RPA
calculations.Comment: Minor revisions according to referee's recomendation
Electron momentum distribution of a single mobile hole in the t-J model
We investigate the electron momentum distribution function (EMDF) for the
two-dimensional t-J model. The results are based on the self-consistent Born
approximation (SCBA) for the self-energy and the wave function. In the Ising
limit of the model we give the results in a closed form, in the Heisenberg
limit the results are obtained numerically. An anomalous momentum dependence of
EMDF is found and the anomaly is in the lowest order in number of magnons
expressed analitycally. We interpret the anomaly as a fingerprint of an
emerging large Fermi surface coexisting with hole pockets.Comment: M2S - submitted to Physica
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