121 research outputs found
Nuclear Shape Fluctuations in Fermi-Liquid Drop Model
Within the nuclear Fermi-liquid drop model, quantum and thermal fluctuations
are considered by use of the Landau-Vlasov-Langevin equation. The spectral
correlation function of the nuclear surface fluctuations is evaluated in a
simple model of an incompressible and irrotational Fermi liquid. The dependence
of the spectral correlation function on the dynamical Fermi-surface distortion
is established. The temperature at which the eigenvibrations become overdamped
is calculated. It is shown that, for realistic values of the relaxation time
parameter and in the high temperature regime, there is a particular eigenmode
of the Fermi liquid drop where the restoring force is exclusively due to the
dynamical Fermi-surface distortion.Comment: 23 pages, revtex, file and 3 figures, accepted for publication in
Nuclear Physics
A New Study of the Transition to Uniform Nuclear Matter in Neutron Stars and Supernovae
A comprehensive microscopic study of the properties of bulk matter at
densities just below nuclear saturation g
cm, zero and finite temperature and high neutron fraction, is outlined,
and preliminary results presented. Such matter is expected to exist in the
inner crust of neutron stars and during the core collapse of massive stars with
$M \gtrsim 8M_{\odot}Comment: 4 pages, 2 figures. Participant Contribution at the ``Dense Matter in
Heavy Ion Collisions and Astrophysics" Summer School, JINR, Dubna, Aug. 21 -
Sept. 1, 2006. To be published in PEPAN letter
Neutron Drops and Skyrme Energy-Density Functionals
The J=0 ground state of a drop of 8 neutrons and the lowest
1/2 and 3/2 states of 7-neutron drops, all in an external well, are
computed accurately with variational and Green's function Monte Carlo methods
for a Hamiltonian containing the Argonne two-nucleon and Urbana IX
three-nucleon potentials. These states are also calculated using Skyrme-type
energy-density functionals. Commonly used functionals overestimate the central
density of these drops and the spin-orbit splitting of 7-neutron drops.
Improvements in the functionals are suggested
Direct Urca Process in a Neutron Star Mantle
We show that the direct Urca process of neutrino emission is allowed in two
possible phases of nonspherical nuclei (inverse cylinders and inverse spheres)
in the mantle of a neutron star near the crust-core interface. The process is
open because neutrons and protons move in a periodic potential created by
inhomogeneous nuclear structures. In this way the nucleons acquire large
quasimomenta needed to satisfy momentum-conservation in the neutrino reaction.
The appropriate neutrino emissivity in a nonsuperfluid matter is about 2--3
orders of magnitude higher than the emissivity of the modified Urca process in
the stellar core. The process may noticeably accelerate the cooling of low-mass
neutron stars.Comment: 7 pages, 3 figures, submitted to A&
The Minimal CFL-Nuclear Interface
At nuclear matter density, electrically neutral strongly interacting matter
in weak equilibrium is made of neutrons, protons and electrons. At sufficiently
high density, such matter is made of up, down and strange quarks in the
color-flavor locked phase, with no electrons. As a function of increasing
density (or, perhaps, increasing depth in a compact star) other phases may
intervene between these two phases which are guaranteed to be present. The
simplest possibility, however, is a single first order phase transition between
CFL and nuclear matter. Such a transition, in space, could take place either
through a mixed phase region or at a single sharp interface with electron-free
CFL and electron-rich nuclear matter in stable contact. Here we construct a
model for such an interface. It is characterized by a region of separated
charge, similar to an inversion layer at a metal-insulator boundary. On the CFL
side, the charged boundary layer is dominated by a condensate of negative
kaons. We then consider the energetics of the mixed phase alternative. We find
that the mixed phase will occur only if the nuclear-CFL surface tension is
significantly smaller than dimensional analysis would indicate.Comment: 30 pages, 7 figure
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