Acceleration-induced nonlocality: kinetic memory versus dynamic memory

The characteristics of the memory of accelerated motion in Minkowski spacetime are discussed within the framework of the nonlocal theory of accelerated observers. Two types of memory are distinguished: kinetic and dynamic. We show that only kinetic memory is acceptable, since dynamic memory leads to divergences for nonuniform accelerated motion.Comment: LaTeX file, 6 PS figures, 34 page

APPLICATIONS OF A FULLY VARIATIONAL METHOD FOR SOLVING ZERO ORDER THOMAS-FERMI EQUATIONS

We present some results obtained in a Thomas-Fermi calculation without restriction of the variational space. We compare them to those obtained with trial functions and to the results of the mean field approximation, in the case of the equation of state of hot dense matter

Stochastic TDHF in an exactly solvable model

We apply in a schematic model a theory beyond mean-field, namely Stochastic Time-Dependent Hartree-Fock (STDHF), which includes dynamical electron-electron collisions on top of an incoherent ensemble of mean-field states by occasional 2-particle-2-hole ($2p2h$) jumps. The model considered here is inspired by a Lipkin-Meshkov-Glick model of $\Omega$ particles distributed into two bands of energy and coupled by a two-body interaction. Such a model can be exactly solved (numerically though) for small $\Omega$. It therefore allows a direct comparison of STDHF and the exact propagation. The systematic impact of the model parameters as the density of states, the excitation energy and the bandwidth is presented and discussed. The time evolution of the STDHF compares fairly well with the exact entropy, as soon as the excitation energy is sufficiently large to allow $2p2h$ transitions. Limitations concerning low energy excitations and memory effects are also discussed.Comment: 23 pages, 8 figures, accepted in Annals of Physic

A SEMI-CLASSICAL DESCRIPTION OF GIANT RESONANCES AT FINITE TEMPERATURE

We present a study of the temperature dependance of the energies of isoscalar giant resonances within a semi-classical model, in the framework of the subtraction procedure of Bonche, Levit and Vautherin This prescription allows a consistent treatment of continuum effects, which play, as we show in detail, a crucial role in the description of excited collective motions. Special attention is paid to the monopole resonance for which 3 moments of the strength function have been calculated. We find a weak temperature dependance of the studied resonance energies (l=0,2,3,4)

A STUDY ON THE FUSION REACTION 139La + 12C AT 50 MeV/u WITH THE VUU EQUATION

Recently Bownan et al. found that in the reaction 139La + 12C at 50 MeV/u a compound nucleus is formed. We simulate this reaction with a numerical solution of the VUU equation and indeed find that for a central collision the system fuses and equilibrates after 90 fm/c

Density functional theory and Kohn-Sham scheme for self-bound systems

We demonstrate how the separation of the total energy of a self-bound system into a functional of the internal one-body Fermionic density and a function of an arbitrary wave vector describing the center-of-mass kinetic energy can be used to set-up an "internal" Kohn-Sham scheme.Comment: 6 pages. To be published in Phys. Rev.

The nuclear equation of state

We present part of our (direct or indirect) knowledge on the equation of state of nuclear matter in a density-temperature domain for which nucleonic effects are dominant (densities smaller than 2-4 times the saturation density and temperatures smaller than 10-20 MeV). The text is divided into three parts corresponding, respectively, to direct studies close to the saturation, to the astrophysical case and to the studies involving heavy-ion collisions. In chapter one, after a brief introduction to the concept of equation of state, we disçuss the saturation property of nuclear matter. The notion of incompressibility modulus is also introduced and its value is discussed in detail. Nuclear matter calculations trying to reproduce saturation from a nucleon-nucleon interaction are also briefly presented. In chapter two we study the equation of state in the astrophysical context. The role of the nuclear component is discussed in detail for the final phase of the collapse of supernovae cores. A brief presentation of calculations of the dense matter constituting neutron stars is also given. Chapter three is devoted to heavy-ion collisions below 500-600 MeV per nucleon. After a brief presentation of both theoretical and experimental frameworks, we focus on three particular aspects which could have a link with the nuclear matter equation of state: the formation of intermediate mass fragments, flow effects and subthreshold particle production