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Title: Role of boundary conditions in dynamic studies of nuclear giant resonances and collisions

Abstract

Absorbing boundary conditions are often employed in time-dependent mean-field calculations to cope with the problem of emitted particles which would otherwise return back onto the system and falsify the dynamical evolution. We scrutinize two widely used methods, imaginary potentials and gradual attenuation by a mask function. To that end, we consider breathing oscillations of a {sup 16}O nucleus computed on a radial one-dimensional grid in coordinate space. The most critical test case is the computation of resonance spectra in the (linear) domain of small amplitude motion. Absorbing bounds turn out to provide a reliable alternative to fully fledged continuum random phase approximation (RPA) calculations, although rather large absorbing bounds are required to simulate reliably well continuum conditions. We also investigate the computation of observables in the nonlinear domain. This regime turns out to be less demanding. Smaller absorbing margin suffice to achieve the wanted absorption effect.

Authors:
 [1];  [2];  [3];  [4];  [5];  [6];  [7];  [8]
  1. Institut fuer Theoretische Physik II, Universitaet Erlangen-Nuernberg, Staudtstrasse 7, D-91058 Erlangen (Germany)
  2. (United States)
  3. Joint Institute for Heavy-Ion Research, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831 (United States)
  4. (United Kingdom)
  5. Department of Physics, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom)
  6. Joint Institute for Heavy-Ion Research, Oak Ridge National Laboratory, P. O. Box 2008, Oak Ridge, Tennessee 37831 (United States)
  7. (Germany)
  8. Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6373 (United States)
Publication Date:
OSTI Identifier:
20778886
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. E, Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics; Journal Volume: 73; Journal Issue: 3; Other Information: DOI: 10.1103/PhysRevE.73.036709; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ATTENUATION; BOUNDARY CONDITIONS; COLLISIONS; COORDINATES; EVOLUTION; FIELD THEORIES; GIANT RESONANCE; HEAVY ION REACTIONS; MEAN-FIELD THEORY; NONLINEAR PROBLEMS; ONE-DIMENSIONAL CALCULATIONS; OSCILLATIONS; OXYGEN 16; POTENTIALS; RANDOM PHASE APPROXIMATION; TIME DEPENDENCE

Citation Formats

Reinhard, P.-G., Joint Institute for Heavy-Ion Research, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831, Stevenson, P.D., Department of Physics, University of Surrey, Guildford, Surrey GU2 7XH, Almehed, D., Maruhn, J.A., Institut fuer Theoretische Physik, Universitaet Frankfurt, Robert-Mayer-Strasse 8-10, D-60325 Frankfurt, and Strayer, M.R. Role of boundary conditions in dynamic studies of nuclear giant resonances and collisions. United States: N. p., 2006. Web. doi:10.1103/PHYSREVE.73.0.
Reinhard, P.-G., Joint Institute for Heavy-Ion Research, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831, Stevenson, P.D., Department of Physics, University of Surrey, Guildford, Surrey GU2 7XH, Almehed, D., Maruhn, J.A., Institut fuer Theoretische Physik, Universitaet Frankfurt, Robert-Mayer-Strasse 8-10, D-60325 Frankfurt, & Strayer, M.R. Role of boundary conditions in dynamic studies of nuclear giant resonances and collisions. United States. doi:10.1103/PHYSREVE.73.0.
Reinhard, P.-G., Joint Institute for Heavy-Ion Research, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831, Stevenson, P.D., Department of Physics, University of Surrey, Guildford, Surrey GU2 7XH, Almehed, D., Maruhn, J.A., Institut fuer Theoretische Physik, Universitaet Frankfurt, Robert-Mayer-Strasse 8-10, D-60325 Frankfurt, and Strayer, M.R. Wed . "Role of boundary conditions in dynamic studies of nuclear giant resonances and collisions". United States. doi:10.1103/PHYSREVE.73.0.
@article{osti_20778886,
title = {Role of boundary conditions in dynamic studies of nuclear giant resonances and collisions},
author = {Reinhard, P.-G. and Joint Institute for Heavy-Ion Research, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831 and Stevenson, P.D. and Department of Physics, University of Surrey, Guildford, Surrey GU2 7XH and Almehed, D. and Maruhn, J.A. and Institut fuer Theoretische Physik, Universitaet Frankfurt, Robert-Mayer-Strasse 8-10, D-60325 Frankfurt and Strayer, M.R.},
abstractNote = {Absorbing boundary conditions are often employed in time-dependent mean-field calculations to cope with the problem of emitted particles which would otherwise return back onto the system and falsify the dynamical evolution. We scrutinize two widely used methods, imaginary potentials and gradual attenuation by a mask function. To that end, we consider breathing oscillations of a {sup 16}O nucleus computed on a radial one-dimensional grid in coordinate space. The most critical test case is the computation of resonance spectra in the (linear) domain of small amplitude motion. Absorbing bounds turn out to provide a reliable alternative to fully fledged continuum random phase approximation (RPA) calculations, although rather large absorbing bounds are required to simulate reliably well continuum conditions. We also investigate the computation of observables in the nonlinear domain. This regime turns out to be less demanding. Smaller absorbing margin suffice to achieve the wanted absorption effect.},
doi = {10.1103/PHYSREVE.73.0},
journal = {Physical Review. E, Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics},
number = 3,
volume = 73,
place = {United States},
year = {Wed Mar 15 00:00:00 EST 2006},
month = {Wed Mar 15 00:00:00 EST 2006}
}