D. Vautherin

Pierre and Marie Curie University - Paris 6, Lutetia Parisorum, Île-de-France, France

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Publications (101)335.15 Total impact

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    P. -H. Heenen · H. Flocard · D. Vautherin
    [Show abstract] [Hide abstract] ABSTRACT: Without Abstract
    Preview · Chapter · Jan 2006
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    Gordon Baym · J.-P. Blaizot · Markus Holzmann · Franck Laloë · Dominique Vautherin
    [Show abstract] [Hide abstract] ABSTRACT: We study the effects of repulsive interactions on the critical density for the Bose-Einstein transition in a homogeneous dilute gas of bosons. First, we point out that the simple mean field approximation produces no change in the critical density, or critical temperature, and discuss the inadequacies of various contradictory results in the literature. Then, both within the frameworks of Ursell operators and of Green's functions, we derive self-consistent equations that include correlations in the system and predict the change of the critical density. We argue that the dominant contribution to this change can be obtained within classical field theory and show that the lowest order correction introduced by interactions is linear in the scattering length, a, with a positive coefficient. Finally, we calculate this coefficient within various approximations, and compare with various recent numerical estimates.
    Preview · Article · Oct 2001 · Physics of Condensed Matter
  • C. Heinemann · D. Vautherin · C. Martin · E. Iancu
    No preview · Article · Jan 2000
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    C. Heinemann · E. Iancu · C. Martin · D. Vautherin
    [Show abstract] [Hide abstract] ABSTRACT: For a SU(N) Yang-Mills theory, we present variational calculations using gaussian wave functionals combined with an approximate projection on gauge invariant states. The projection amounts to correcting the energy of the gaussian states by substracting the spurious energy associated with gauge rotations. Based on this improved energy functional, we perform variational calculations of the interaction energy in the presence of external electric and magnetic fields. We verify that the ultraviolet behaviour of our approximation scheme is consistent, as it should, with that expected from perturbation theory. In particular, we recover in this variational framework the standard one-loop beta function, with a transparent interpretation of the screening and anti-screening contributions. Comment: 40 pages, no figures
    Full-text · Article · Nov 1999 · Physical review D: Particles and fields
  • J. Navarro · E. S. Hernández · D. Vautherin
    No preview · Article · Jul 1999 · Nuclear Physics A
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    [Show abstract] [Hide abstract] ABSTRACT: We show that the critical temperature of a uniform dilute Bose gas must increase linearly with the s-wave scattering length describing the repulsion between the particles. Because of infrared divergences, the magnitude of the shift cannot be obtained from perturbation theory, even in the weak coupling regime; rather, it is proportional to the size of the critical region in momentum space. By means of a self-consistent calculation of the quasiparticle spectrum at low momenta at the transition, we find an estimate of the effect in reasonable agreement with numerical simulations.
    Preview · Article · Jun 1999 · Physical Review Letters
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    J. Navarro · E. S. Hernández · D. Vautherin
    [Show abstract] [Hide abstract] ABSTRACT: We present microscopic calculations of neutrino propagation in hot neutron matter above nuclear density within the framework of the Random Phase Approximation . Calculations are performed for non- degenerate neutrinos using various Skyrme effective interactions. We find that for densities just above nuclear density, spin zero sound is present at zero temperature for all Skyrme forces considered. However it disappears rapidly with increasing temperature due to a strong Landau damping. As a result the mean-free path is given, to a good approximation, by the mean field value. Because of the renormalization of the bare mass in the mean field, the medium is more transparent as compared to the free case. We find, in contrast, that at several times nuclear density, a new type of behavior sets in due to the vicinity of a magnetic instability. It produces a strong reduction of the mean free path. The corresponding transition density however occurs in a region where inputs from more realistic calculations are necessary for the construction of a reliable Skyrme type parametrization. Comment: 17 pages, 4 figures
    Preview · Article · Jan 1999 · Physical Review C
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    Yasuhiko Tsue · Dominique Vautherin · Tetsuo Matsui
    [Show abstract] [Hide abstract] ABSTRACT: Mean field theory for the time evolution of quantum meson fields is studied in terms of the functional Schroedinger picture with a time-dependent Gaussian variational wave functional. We first show that the equations of motion for the variational wavefunctional can be rewritten in a compact form similar to the Hartree-Bogoliubov equations in quantum many-body theory and this result is used to recover the covariance of the theory. We then apply this method to the O(N) model and present analytic solutions of the mean field evolution equations for an N-component scalar field. These solutions correspond to quantum rotations in isospin space and represent generalizations of the classical solutions obtained earlier by Anselm and Ryskin. As compared to classical solutions new effects arise because of the coupling between the average value of the field and its quantum fluctuations. We show how to generalize these solutions to the case of mean field dynamics at finite temperature. The relevance of these solutions for the observation of a coherent collective state or a disoriented chiral condensate in ultra-relativistic nuclear collisions is discussed. Comment: 31 pages, 2 Postscript figures, uses ptptex.sty
    Preview · Article · Dec 1998 · Progress of Theoretical Physics
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    D. Vautherin · T. Matsui
    [Show abstract] [Hide abstract] ABSTRACT: Analytic solutions of the mean field evolution equations for an N-component scalar field with O(N) symmetry are presented. These solutions correspond to rotations in isospin space. They represent generalizations of the classical solutions obtained earlier by Anselm and Ryskin. As compared to classical solutions new effects arise because of the coupling between the average value of the field and quantum fluctuations.
    Preview · Article · Oct 1998 · Physics Letters B
  • [Show abstract] [Hide abstract] ABSTRACT: Radii of sodium isotopes have been calculated by using the Hartree-Fock-BCS model and the Generator Coordinate Method (GCM) with different forces. It is found that Hartree-Fock-BCS results present a jump in both neutron and proton radii from 22Na to 23Na. However, configuration mixing calculations performed with the GCM result in a smooth increase of the neutron radius and an almost constant proton radius for the sodium isotopes. We analyze and discuss our results in the light of recent experimental data.
    No preview · Article · Jun 1998 · Physics Letters B
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    C. Heineman · C. Martin · D. Vautherin · E. Iancu
    [Show abstract] [Hide abstract] ABSTRACT: Variational calculations using Gaussian wave functionals combined with an approximate projection on gauge invariant states are presented. We find that the energy exhibits a minimum for a wave functional centered around a non vanishing background magnetic field. We show that divergences can be removed by a renormalization of the coupling constant. The resulting expectation value of the gluon condensate is found to be in qualitative agreement with phenomenological estimates.
    Full-text · Article · Mar 1998
  • S. Ménard · J. P Schapira · D. Vautherin · P. Bonche
    [Show abstract] [Hide abstract] ABSTRACT: We present a simple model to calculate energy distributions and multiplicities of the neutrons emitted in the interaction of a high-energy proton with a thick target. It is based on a dEdx formula proposed by Cugnon for the proton energy loss inside nuclear matter and on the assumption that the dissipated energy eventually becomes thermalized. Comparison with the results of existing codes and available data is made. An application to the determination of the sensitivity of multiplicities to various input parameters (e.g. the level density parameter) is described. The model is shown to provide further physical insight into the standard spallation codes.
    No preview · Article · Dec 1997 · Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment
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    D. Vautherin · T. Matsui
    [Show abstract] [Hide abstract] ABSTRACT: We construct asymptotic solutions of the functional Schroedinger equation for a scalar field in the Gaussian approximation at large proper time. These solutions describe the late proper time stages of the expansion of a meson gas with boost invariant boundary conditions. The relevance of these solutions for the formation of a disoriented chiral condensate in ultra relativistic collisions is discussed. Comment: 9 pages, LATEX
    Preview · Article · Sep 1996 · Physical Review D
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    Abdellatif Abada · Dominique Vautherin
    [Show abstract] [Hide abstract] ABSTRACT: The description of collective motion in nuclei at finite temperature using the framework of the random phase approximation is discussed. We focus on the special case of the isovector response function of hot nuclear matter using various effective Skyrme interactions.
    Preview · Article · Nov 1995
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    Fábio L. Braghin · Dominique Vautherin · Abdellatif Abada
    [Show abstract] [Hide abstract] ABSTRACT: We investigate the role of the effective nucleon-nucleon interaction in the description of giant dipole resonances in hot nuclei. For this purpose we calculate the response function of hot nuclear matter to a small isovector external perturbation using various effective Skyrme interactions. We find that for Skyrme forces with an effective mass close to unity an undamped zero sound mode occurs at zero temperature. This mode gives rise in finite nuclei (calculated via the Steinwedel-Jenssen model) to a resonance whose energy agrees with the observed value. We find that zero sound disappears at a temperature of a few MeV, leaving only a broad peak in the dipole strength. For Skyrme forces with a small value of the effective mass (0.4- 0.5), there is no zero sound at zero temperature but only a weak peak located too high in energy. The strength distribution in this case is nearly independent of temperature and shows small collective effects. The relevance of these results for the saturation of photon multiplicities observed in recent experiments is pointed out.
    Full-text · Article · Jun 1995 · Physical Review C
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    Abdellatif Abada · Fabio L. Braghin · Dominique Vautherin
    [Show abstract] [Hide abstract] ABSTRACT: We calculate the isovector response function of hot nuclear matter using various effective Skyrme interactions. For Skyrme forces with a small effective mass the strength distribution is found to be nearly independent of temperature, and shows little collective effects. In contrast effective forces with an effective mass close to unity produce sizeable collective effects at zero temperature which disappear at temperatures of a few MeV. We discuss the relevance of these results for the saturation of the multiplicity of photons emitted by the giant dipole resonance in hot nuclei beyond $T$=3 MeV observed in recent experiments.
    Full-text · Article · Feb 1995
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    F.L. Braghin · C. Martin · D. Vautherin
    [Show abstract] [Hide abstract] ABSTRACT: We consider the functional Schrodinger equation for a self interacting scalar field in an expanding geometry. By performing a time dependent scale transformation on the argument of the field we derive a functional Schrodinger equation whose hamiltonian is time independent but involves a time-odd term associated to a constraint on the expansion current. We study the mean field approximation to this equation and generalize in this case, for interacting fields, the solutions worked out by Bunch and Davies for free fields. Comment: 8 pages, Latex, IPNO/TH 94-39
    Full-text · Article · May 1994 · Physics Letters B
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    F.L. Braghin · D. Vautherin
    [Show abstract] [Hide abstract] ABSTRACT: We investigate the response function of hot nuclear matter to a small isovector external field using a simplified Skyrme interaction reproducing the value of the symmetry energy coefficient. We consider values of the momentum transfer corresponding to the dipole oscillation in heavy nuclei. We find that while at zero temperature the particle hole interaction is almost repulsive enough to have a sharp (zero sound type) collective oscillation, such is no longer the case at temperatures of a few MeV. As a result a broadening of the dipole resonance occurs, leading to its quasi disappearance by the time the temperature reaches 5 MeV. The sensitivity of the temperature evolution of the width when modifying the residual interaction strength is also examined.
    Full-text · Article · Apr 1994 · Physics Letters B
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    Cécile Martin · Dominique Vautherin
    [Show abstract] [Hide abstract] ABSTRACT: We describe a nonperturbative calculation of the spectrum of SU(2) Yang-Mills theory based on a Hamiltonian formulation. Our approach exploits gauge invariant variables similar to those used in nuclear physics to describe collective motion in nuclei. Comment: 18 pages Latex
    Preview · Article · Jan 1994 · Nuclear Physics B - Proceedings Supplements
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    Abdellatif Abada · Dominique Vautherin
    [Show abstract] [Hide abstract] ABSTRACT: Two phonon-states of alkali-metal clusters (treated as jellium spheres) are calculated by using a method based on a perturbative construction of periodic orbits of the time-dependent mean-field equations. Collective vibrations with various multipolarities in charged $Na^+_{21}$ are considered.
    Preview · Article · Apr 1993

Publication Stats

6k Citations
335.15 Total Impact Points

Institutions

  • 1998
    • Pierre and Marie Curie University - Paris 6
      Lutetia Parisorum, Île-de-France, France
  • 1989
    • Centro de Estudios y Experimentación de Obras Públicas
      Madrid, Madrid, Spain
  • 1975-1989
    • Institut de Physique Nucléaire de Lyon
      Lyons, Rhône-Alpes, France
  • 1975-1986
    • Orsay Physics
      Fuveau, Provence-Alpes-Côte d'Azur, France
  • 1983
    • Université Libre de Bruxelles
      • Theoretical Physics Unit
      Bruxelles, Brussels Capital, Belgium
  • 1977
    • University of California, Berkeley
      Berkeley, California, United States
  • 1970-1976
    • University of Oxford
      Oxford, England, United Kingdom
  • 1972
    • Massachusetts Institute of Technology
      Cambridge, Massachusetts, United States