Dr Arnau Rios Huguet
Advanced Fellow
Qualifications: PhD
Email: a.rios@surrey.ac.uk
Phone: Work: 01483 68 9412
Room no: 13 BB 03
Further information
Biography
Further details can be found on my personal web page.
A full list of publications, conference presentations, and patents can be found here.
Publications
Highlights
- .
(2012) 'Self-consistent Green's functions calculation of the nucleon mean free path'. American Physical Society Physical Review Letters, 108 Article number 012501 Full text is available at: http://epubs.surrey.ac.uk/111027/
Abstract
The extension of Green’s functions techniques to the complex energy plane provides access to fully dressed quasiparticle properties from a microscopic perspective. Using self-consistent ladder selfenergies, we find both spectra and lifetimes of such quasiparticles in nuclear matter. With a consistent choice of the group velocity, the nucleon mean-free path can be computed. Our results indicate that, for energies above 50 MeV at densities close to saturation, a nucleon has a mean-free path of 4 to 5 fm.
- .
(2009) 'Density dependence of the nuclear symmetry energy: A microscopic perspective'. American Physical Society Physical Review C, 80 (4) Article number 045806 Full text is available at: http://epubs.surrey.ac.uk/7123/
Abstract
We perform a systematic analysis of the density dependence of nuclear symmetry energy within the microscopic Brueckner-Hartree-Fock (BHF) approach using the realistic Argonne V18 nucleon-nucleon potential plus a phenomenological three-body force of Urbana type. Our results are compared thoroughly with those arising from several Skyrme and relativistic effective models. The values of the parameters characterizing the BHF equation of state of isospin asymmetric nuclear matter fall within the trends predicted by those models and are compatible with recent constraints coming from heavy ion collisions, giant monopole resonances, or isobaric analog states. In particular we find a value of the slope parameter L=66.5 MeV, compatible with recent experimental constraints from isospin diffusion, L=88±25 MeV. The correlation between the neutron skin thickness of neutron-rich isotopes and the slope L and curvature Ksym parameters of the symmetry energy is studied. Our BHF results are in very good agreement with the correlations already predicted by other authors using nonrelativistic and relativistic effective models. The correlations of these two parameters and the neutron skin thickness with the transition density from nonuniform to β-stable matter in neutron stars are also analyzed. Our results confirm that there is an inverse correlation between the neutron skin thickness and the transition density.
- .
(2009) 'Hot neutron matter from a self-consistent Green's-functions approach'. American Physical Society Physical Review C (Nuclear Physics), 79 Article number 025802 Full text is available at: http://epubs.surrey.ac.uk/121741/
Abstract
A systematic study of the microscopic and thermodynamical properties of pure neutron matter at finite temperature within the self-consistent Green's-function approach is performed. The model dependence of these results is analyzed by both comparing the results obtained with two different microscopic interactions, the CD Bonn and the Argonne V18 potentials, and by analyzing the results obtained with other approaches, such as the Brueckner-Hartree-Fock approximation, the variational approach, and the virial expansion.
- .
(2008) 'Liquid-gas phase transition in nuclear matter from realistic many-body approaches'. American Physical Society Physical Review C (Nuclear Physics), 78 Article number 044314 Full text is available at: http://epubs.surrey.ac.uk/121740/
Abstract
The existence of a liquid-gas phase transition for hot nuclear systems at subsaturation densities is a well-established prediction of finite-temperature nuclear many-body theory. In this paper, we discuss for the first time the properties of such a phase transition for homogeneous nuclear matter within the self-consistent Green's function approach. We find a substantial decrease of the critical temperature with respect to the Brueckner-Hartree-Fock approximation. Even within the same approximation, the use of two different realistic nucleon-nucleon interactions gives rise to large differences in the properties of the critical point.
Journal articles
- .
(2012) 'Comparative study of neutron and nuclear matter with simplifi ed Argonne nucleon-nucleon potentials'. American Physical Society Physical Review C: Nuclear Physics, 86 (6) Article number 064001 Full text is available at: http://epubs.surrey.ac.uk/743161/
Abstract
We present calculations of the energy per particle of pure neutron and symmetric nuclear matter with simplified Argonne nucleon-nucleon potentials for different many-body theories. We compare critically the Brueckner-Hartree-Fock results to other formalisms, such as the Brueckner-Bethe-Goldstone expansion up to third order, self-consistent Green's functions, auxiliary field diffusion Monte Carlo, and Fermi hypernetted chain. We evaluate the importance of spin-orbit and tensor correlations in the equation of state and find these to be important in a wide range of densities.
- .
(2012) 'High-momentum components in the nuclear symmetry energy'. EDP Sciences Europhysics Letters: a letters journal exploring the frontiers of physics, 97 Article number 22001 Full text is available at: http://epubs.surrey.ac.uk/121087/
Abstract
The short-range and tensor correlations associated to realistic nucleon-nucleon interactions induce a population of high-momentum components in the many-body nuclear wave function. We study the impact of such high-momentum components on bulk observables associated to isospin asymmetric matter. The kinetic part of the symmetry energy is strongly reduced by correlations when compared to the non-interacting case. The origin of this behavior is elucidated using realistic interactions with different short-range and tensor structures.
- .
(2012) 'Self-consistent Green's functions calculation of the nucleon mean free path'. American Physical Society Physical Review Letters, 108 Article number 012501 Full text is available at: http://epubs.surrey.ac.uk/111027/
Abstract
The extension of Green’s functions techniques to the complex energy plane provides access to fully dressed quasiparticle properties from a microscopic perspective. Using self-consistent ladder selfenergies, we find both spectra and lifetimes of such quasiparticles in nuclear matter. With a consistent choice of the group velocity, the nucleon mean-free path can be computed. Our results indicate that, for energies above 50 MeV at densities close to saturation, a nucleon has a mean-free path of 4 to 5 fm.
- .
(2011) 'Towards a nonequilibrium Green's function description of nuclear reactions: One-dimensional mean-field dynamics'. Elsevier Annals of Physics, 326 (5), pp. 1274-1319.Full text is available at: http://epubs.surrey.ac.uk/7126/
Abstract
Nonequilibrium Green’s function methods allow for an intrinsically consistent description of the evolution of quantal many-body body systems, with inclusion of different types of correlations. In this paper, we focus on the practical developments needed to build a Green’s function methodology for nuclear reactions. We start out by considering symmetric collisions of slabs in one dimension within the mean-field approximation. We concentrate on two issues of importance for actual reaction simulations. First, the preparation of the initial state within the same methodology as for the reaction dynamics is demonstrated by an adiabatic switching on of the mean-field interaction, which leads to the mean-field ground state. Second, the importance of the Green’s function matrix-elements far away from the spatial diagonal is analyzed by a suitable suppression process that does not significantly affect the evolution of the elements close to the diagonal. The relative lack of importance of the far-away elements is tied to system expansion. We also examine the evolution of the Wigner function and verify quantitatively that erasing of the off-diagonal elements corresponds to averaging out of the momentum–space details in the Wigner function.
- .
(2011) 'Latent heat of nuclear matter'. American Physical Society Physical Review C (Nuclear Physics), 83 (2) Article number 024308 Full text is available at: http://epubs.surrey.ac.uk/7125/
Abstract
We study the latent heat of the liquid-gas phase transition in symmetric nuclear matter using self-consistent mean-field calculations with a few Skyrme forces. The temperature dependence of the latent heat is rather independent of the mean-field parametrization and it can be characterized by a few parameters. At low temperatures, the latent heat tends to the saturation energy. Near the critical point, the latent heat goes to zero with a well-determined mean-field critical exponent. A maximum value of the latent heat in the range l similar to 25-30 MeV is found at intermediate temperatures, which might have experimental relevance. All these features can be explained from very basic principles.
- .
(2011) 'Symmetry Energy, Neutron Star Crust and Neutron Skin Thickness'. Springer Few Body Physics, 50 (1-4), pp. 327-329.Full text is available at: http://epubs.surrey.ac.uk/7909/
- .
(2011) 'Role of short-range and tensor correlations in nuclei'. Institute of Physics Journal of Physics, Conference Series, 321 (1) Article number 012038 Full text is available at: http://epubs.surrey.ac.uk/7389/
Abstract
The role of short-range and tensor correlations in nuclei can be investigated through a careful comparison with microscopic nuclear matter calculations. We focus on the momentum distribution, a one-body operator which is particularly sensitive to correlations. We identify a depletion of the population of hole states of around 15% in symmetric matter and a significant isospin dependence due to the tensor force. The increased role of short-range and tensor correlations for the minority species makes the case for further experimental scrutiny of nuclei with large neutron excess.
- .
(2011) 'Liquid-gas phase transition in nuclear matter in the mean-field approximation'. Institute of Physics Journal of Physics, Conference Series, 321 (1) Article number 012058 Full text is available at: http://epubs.surrey.ac.uk/7391/
Abstract
The liquid gas phase transition in nuclear systems is a unique phenomenon, at the frontier of nuclear, many-body and statistical physics. We use self-consistent mean-field calculations to quantify the properties of the transition in symmetric nuclear matter. We explore the available parameter space of critical properties by analyzing the mean-field dependence of the phase transition. The latent heat of the transition is computed and we find that it exhibits a model independent temperature dependence due to basic physical principles.
- .
(2011) 'Role of short-range and tensor correlations in nuclei'. Institute of Physics Journal of Physics, Conference Series, 312 (2) Article number 022007 Full text is available at: http://epubs.surrey.ac.uk/13485/
Abstract
The present theoretical understanding of the role of short-range correlations in nuclei near stability is reviewed. Two effects are identified in particular: first, the depletion of mean-field single-particle strength that is no longer available to participate in low-lying excitations. Second, the admixture of high-momentum nucleons in the ground state that is implied by the vanishing relative wave functions of pairs in the medium. The role of the tensor force will be further clarified by discussing isospin-polarized matter. It is demonstrated that the depletion of the proton and neutron Fermi seas depends strongly on the nuclear tensor force and appears to be determined by nucleon-nucleon scattering data. The increased role of short-range and tensor correlations for the minority species makes the case for further experimental scrutiny of nuclei with large neutron excess. Appropriate data of single- and two-nucleon knockout experiments are employed to illustrate the role of short-range and tensor correlations.
- .
(2010) 'Nucleon correlations and the equation of state of nuclear matter'. American Institute of Physics AIP Conference Proceedings, 1322 Article number 99 , pp. 99-107.doi: 10.1063/1.3542037Full text is available at: http://epubs.surrey.ac.uk/7390/
Abstract
The self-consistent Green's function method within the ladder approximation provides a microscopic description of correlated nuclear systems which properly treats the nucleon-nucleon correlations induced by the short-range and tensor components present in any realistic interaction. These correlations produce a sizable depletion of low momenta below the Fermi surface as well as the occupation of high momenta in the nuclear ground state. A few representative results for nuclear matter are presented to illustrate the present progress in the application of this method to nuclear systems
- .
(2010) 'Effective interaction dependence of the liquid-gas phase transition in symmetric nuclear matter'. ELSEVIER SCIENCE BV NUCLEAR PHYSICS A, 845, pp. 58-87.Full text is available at: http://epubs.surrey.ac.uk/7124/
- .
(2009) 'Density dependence of the nuclear symmetry energy: A microscopic perspective'. American Physical Society Physical Review C, 80 (4) Article number 045806 Full text is available at: http://epubs.surrey.ac.uk/7123/
Abstract
We perform a systematic analysis of the density dependence of nuclear symmetry energy within the microscopic Brueckner-Hartree-Fock (BHF) approach using the realistic Argonne V18 nucleon-nucleon potential plus a phenomenological three-body force of Urbana type. Our results are compared thoroughly with those arising from several Skyrme and relativistic effective models. The values of the parameters characterizing the BHF equation of state of isospin asymmetric nuclear matter fall within the trends predicted by those models and are compatible with recent constraints coming from heavy ion collisions, giant monopole resonances, or isobaric analog states. In particular we find a value of the slope parameter L=66.5 MeV, compatible with recent experimental constraints from isospin diffusion, L=88±25 MeV. The correlation between the neutron skin thickness of neutron-rich isotopes and the slope L and curvature Ksym parameters of the symmetry energy is studied. Our BHF results are in very good agreement with the correlations already predicted by other authors using nonrelativistic and relativistic effective models. The correlations of these two parameters and the neutron skin thickness with the transition density from nonuniform to β-stable matter in neutron stars are also analyzed. Our results confirm that there is an inverse correlation between the neutron skin thickness and the transition density.
- .
(2009) 'Hot neutron matter from a self-consistent Green's-functions approach'. American Physical Society Physical Review C (Nuclear Physics), 79 Article number 025802 Full text is available at: http://epubs.surrey.ac.uk/121741/
Abstract
A systematic study of the microscopic and thermodynamical properties of pure neutron matter at finite temperature within the self-consistent Green's-function approach is performed. The model dependence of these results is analyzed by both comparing the results obtained with two different microscopic interactions, the CD Bonn and the Argonne V18 potentials, and by analyzing the results obtained with other approaches, such as the Brueckner-Hartree-Fock approximation, the variational approach, and the virial expansion.
- .
(2008) 'Liquid-gas phase transition in nuclear matter from realistic many-body approaches'. American Physical Society Physical Review C (Nuclear Physics), 78 Article number 044314 Full text is available at: http://epubs.surrey.ac.uk/121740/
Abstract
The existence of a liquid-gas phase transition for hot nuclear systems at subsaturation densities is a well-established prediction of finite-temperature nuclear many-body theory. In this paper, we discuss for the first time the properties of such a phase transition for homogeneous nuclear matter within the self-consistent Green's function approach. We find a substantial decrease of the critical temperature with respect to the Brueckner-Hartree-Fock approximation. Even within the same approximation, the use of two different realistic nucleon-nucleon interactions gives rise to large differences in the properties of the critical point.