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Piotr Magierski

Publications and source records attributed to Piotr Magierski.

68 records · Page 4Linked to original sources
arXiv2002

Exotic nuclear phases in the inner crust of neutron stars in the light of Skyrme-Hartree-Fock theory

The bottom part of the neutron star crust is investigated using the Skyrme-Hartree-Fock approach with the Coulomb interaction treated beyond the Wigner-Seitz approximation. A variety of nuclear phases is found to coexist in this region. Their stability and relative energies are governed by the Coulomb, surface and shell energies. We have also found that a substantial contribution is coming from the spin-orbit interaction.

nucl-th↗
arXiv2002

Quantum corrections to the ground state energy of inhomogeneous neutron matter

We estimate the quantum corrections to the ground state energy in neutron matter (which could be termed as well either shell correction energy or Casimir energy) at subnuclear densities, where various types of inhomogeneities (bubbles, rods, plates) are energetically favorable. We show that the magnitude of these energy corrections are comparable to the energy differences between various types of inhomogeneous phases. We discuss the dependence of these corrections on a number of physical parameters (density, filling factor, temperature, lattice distortions).

astro-ph↗
arXiv2001

Structure of the inner crust of neutron stars: crystal lattice or disordered phase ?

We investigate the inner crust structure of neutron stars using the Skyrme-Hartree-Fock approach with the Coulomb interaction treated beyond the Wigner-Seitz approximation. Our results suggest that the shell effects associated with unbound neutrons play an important role and, in particular, lead to complicated phase transition pattern between various nuclear phases (as a function of the density). Namely, we show that the relative energies of different phases are rapidly oscillating functions of the neutron density. In the semiclassical approach this behavior is explained as an interference effect due to periodic orbits of similar lengths. We discuss also the dependence of the shell effects on pairing correlations.

nucl-th↗
arXiv2001

Selected aspects of physics of fermionic bubbles

We discuss properties of the Fermi system which contain one or more spherical (or almost spherical) objects. The interplay between various effects, such as shell correction and chaotic behavior is considered. We briefly mention the role of the temperature, pairing, and effects associated with bubble dynamics.

cond-mat↗
arXiv2001

Properties of nuclei in the neutron star crust

In the present study we investigate the static properties of nuclei in the inner crust of neutron stars. Using the Hartree-Fock method in coordinate space, together with the semiclassical approximation, we examine the patterns of phase transitions.

nucl-th↗
arXiv2001

Neutron stars and the fermionic Casimir effect

The inner crust of neutron stars consists of nuclei of various shapes immersed in a neutron gas and stabilized by the Coulomb interaction in the form of a crystal lattice. The scattering of neutrons on nuclear inhomegeneities leads to the quantum correction to the total energy of the system. This correction resembles the Casimir energy and turns out to have a large influence on the structure of the crust.

nucl-th↗
arXiv2000

Neutron Stars and Quantum Billiards

Homogeneous neutron matter at subnuclear densities becomes unstable towards the formation of inhomogeneities. Depending on the average value of the neutron density one can observe the appearance of either bubbles, rods, tubes or plates embeded in a neutron gas. We estimate the quantum corrections to the ground state energy (which could be termed either shell correction or Casimir energy) of such phases of neutron matter. The calculations are performed by evaluating the contribution of the shortest periodic orbits in the Gutzwiller trace formula for the density of states. The magnitude of the quantum corrections to the ground state energy of neutron matter are of the same order as the energy differences between various phases.

astro-ph↗
arXiv1999

Shell correction energy for bubble nuclei

The positioning of a bubble inside a many fermion system does not affect the volume, surface or curvature terms in the liquid drop expansion of the total energy. Besides possible Coulomb effects, the only other contribution to the ground state energy of such a system arises from shell effects. We show that the potential energy surface is a rather shallow function of the displacement of the bubble from the center and in most cases the preferential position of a bubble is off center. Systems with bubbles are expected to have bands of extremely low lying collective states, corresponding to various bubble displacements.

nucl-th↗
arXiv1999

Selfconsistent effective interactions and symmetry restoration

In this paper we propose a general framework for deriving the effective interactions for many-body systems. We show how the selfconsistent interaction can be constructed on the quantum level for both local and nonlocal potentials. In particular the relation between the selfconsistent and symmetry restoring interaction is derived. The difference between the two is related to the coupling of the perturbing field to the kinetic energy operator.

nucl-th↗
arXiv1999

Eigenstates for billiards of arbitrary shapes

A new algorithm for determining the eigenstates of n-dimensional billiards is presented. It is based on the application of the Cauchy theorem for the determination of the null space of the boundary overlap matrix. The method is free from the limitations associated with the shape of the billiard and could be applied even for nonconvex geometries where other algorithms face difficulties. Moreover it does not suffer from the existence of eigenvalue degeneracies which is another serious shortcoming of many methods. In the paper we apply the algorithm to a few simple cases where the analytical solutions exist. Numerical solutions have been investigated for the case of annular billiard.

physics.comp-ph↗
arXiv1998

Fermionic and Bosonic Bubbles and Foam

The positioning of one or more bubbles inside a many fermion or boson system, does not affect the volume, surface or curvature terms in the liquid drop expansion of the total energy. If Coulomb effects are irrelevant, the only contribution to the ground state energy of a system with one or more voids arises from quantum effects, which is similar to the Casimir effect in vacuum or in critical phenomena. We discuss the characteristics of such systems, the interplay among various effects, such as shell corrections and chaotic behavior, and briefly mention the role of the temperature and pairing.

nucl-th↗