F. V. De Blasio

Nucleation and vitrification of a dense plasma

We apply the classical theory of homogeneous nucleation to a classical one-component plasma. Nucleation and growth rates are discussed for systems at high density. Calculations show the refratoriness of this system to form glass.

Pinning properties of superfluid vortices in the crust of neutron stars

SummaryWe evaluate the neutron superfluid pinning energy in the inner crust of a neutron star, where a gas of free neutrons cohexists with a lattice of neutron-rich nuclei, in the framework of the local density approximation and using Gogny effective force. We find that non-uniform pairing gap of the superfluid neutrons strongly affects the pinning properties of a vortex-nucleus system. Clear evidence for strong, weak and superweak pinning regimes are given. Comparison of our results with previous calculations are also shown.

Vortex pinning with non-spherical nuclei

We investigate the pinning energies of superfluid vortex lines inside the inner crust of a neutron star taking into account the presence of nuclei with non-spherical shapes. It is found that vortex lines pin to the unusual nuclei with an energy larger respect to the spherical case.

Pairing properties of clustered protons in neutron star crusts

Using BCS formalism at finite temperature we evaluate the pairing gap and the specific heat of protons clustered in the spherical lattice nuclei of neutron star crust. It is found a negligible protonic contribution to the overall heat capacity of the neutron star crust.

Semi-classical description of the neutron superfluid in the inner crust of neutron stars

SummaryThe model of a Wigner-Seitz cell consisting of a nucleus embedded in a sea of neutrons is examined with particular attention to the pairing properties of the superfluid neutron liquid. The model describes microscopically the status of baryonic matter inside the inner crust of neutron stars, where it is assumed that neutron-rich nuclei disposed in a Coulomb lattice are permeated by a sea of superfluid neutrons at very low temperature. A semi-classical approach based on the local density approximation is followed in order to describe thenon-uniform pairing gap in the Wigner-Seitz cell, and the Gogny force is used to represent the nucleon-nucleon interaction. In the range of physically relevant densities, we find a neutron pairing gap which is generally larger in the region of the cell outside the nucleus. This behaviour should have consequences on the physics of neutron stars, like cooling patterns and pinning of vortices in rotating stars.

Specific heat of the superfluid neutron matter in neutron star crusts

We calculate the specific heat of superfluid neutrons in the inner crust of neutron stars, taking into account the role played by the nuclei in the lattice. We have found a strong increase in the calculated specific heat respect to that associated with a uniform neutron superfluid.

Protons in non-spherical nuclear phases of a neutron star crust

SummaryWe discuss the pairing properties of the protonic component of cylindrical and slab-shaped nuclear clusters proposed as lattice nuclei in the deeper part of a neutron star crust. We assume that protons in these structures are superconducting and find a proton pairing energy gap that decreases with density from cylindrical to slab nuclei.

Nucleation of a One-Component Plasma and Structure of Neutron Star Crusts.

SummaryThe homogeneous nucleation at constant temperature of a one-component plasma is studied and possible consequences for the structure of neutron star crusts are examined.

Specific heat of protons in non-spherical nuclei

We study the role played by the protons clustered in non-spherical neutron star crust nuclei in terms of contribution to the total fermionic specific heat. We find that in the deeper part of the crust protons play a non marginal role on the thermodynamical properties of the crust.

HEAT DIFFUSION TIME IN NEUTRON STAR CRUSTS

We examine the role of the crust heat capacity on the cooling history of a neutron star. We find that taking into account the non-uniform structure of the crust, a sizeable increase in the heat diffusion time should be expected.