Dr Carlo Barbieri
Senior Lecturer
Email: c.barbieri@surrey.ac.uk
Phone: Work: 01483 68 9327
Room no: 03 BB 03
Further information
Research Interests
Carlo Barbieri Personal Research Page
Publications
Highlights
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(2013) 'Ab initio Gorkov-Green's function calculations of open-shell nuclei'. Physical Review C - Nuclear Physics, 87 (1)Full text is available at: http://epubs.surrey.ac.uk/762841/
Abstract
We present results from a new ab initio method that uses the self-consistent Gorkov-Green's function theory to address truly open-shell systems. The formalism has been recently worked out up to second order and is implemented here in nuclei on the basis of realistic nuclear forces. Benchmark calculations indicate that the method is in agreement with other ab initio approaches in doubly closed shell 40Ca and 48Ca. We find good convergence of the results with respect to the basis size in 44Ca and 74Ni and discuss quantities of experimental interest including ground-state energies, pairing gaps, and particle addition and removal spectroscopy. These results demonstrate that the Gorkov method is a valid alternative to multireference approaches for tackling degenerate or near-degenerate quantum systems. In particular, it increases the number of mid-mass nuclei accessible in an ab initio fashion from a few tens to a few hundred. © 2013 American Physical Society.
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(2011) 'Ab initio self-consistent Gorkov-Green's function calculations of semimagic nuclei: Formalism at second order with a two-nucleon'. American Physical Society Physical Review C (Nuclear Physics), 84 (6) Article number 064317 Full text is available at: http://epubs.surrey.ac.uk/121079/
Abstract
An ab initio calculation scheme for finite nuclei based on self-consistent Green's functions in the Gorkov formalism is developed. It aims at describing properties of doubly magic and semimagic nuclei employing state-of-the-art microscopic nuclear interactions and explicitly treating pairing correlations through the breaking of U(1) symmetry associated with particle number conservation. The present paper introduces the formalism necessary to undertake applications at (self-consistent) second order using two-nucleon interactions in a detailed and self-contained fashion. First applications of such a scheme will be reported soon in a forthcoming publication. Future works will extend the present scheme to include three-nucleon interactions and implement more advanced truncation schemes.
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(2011) 'Microscopic self-energy calculations and dispersive optical-model potentials'. AMER PHYSICAL SOC PHYSICAL REVIEW C, 84 (3) Article number ARTN 034616 Full text is available at: http://epubs.surrey.ac.uk/26821/
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(2011) 'Faddeev random-phase approximation for molecules'. American Physical Society Physical Review A - Atomic, Molecular, and Optical Physics, 83 (4)Full text is available at: http://epubs.surrey.ac.uk/26822/
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(2009) 'Role of Long-Range Correlations in the Quenching of Spectroscopic Factors'. AMER PHYSICAL SOC PHYSICAL REVIEW LETTERS, 103 (20) Article number ARTN 202502 Full text is available at: http://epubs.surrey.ac.uk/26824/
Journal articles
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(2013) 'Ab initio Gorkov-Green's function calculations of open-shell nuclei'. Physical Review C - Nuclear Physics, 87 (1)Full text is available at: http://epubs.surrey.ac.uk/762841/
Abstract
We present results from a new ab initio method that uses the self-consistent Gorkov-Green's function theory to address truly open-shell systems. The formalism has been recently worked out up to second order and is implemented here in nuclei on the basis of realistic nuclear forces. Benchmark calculations indicate that the method is in agreement with other ab initio approaches in doubly closed shell 40Ca and 48Ca. We find good convergence of the results with respect to the basis size in 44Ca and 74Ni and discuss quantities of experimental interest including ground-state energies, pairing gaps, and particle addition and removal spectroscopy. These results demonstrate that the Gorkov method is a valid alternative to multireference approaches for tackling degenerate or near-degenerate quantum systems. In particular, it increases the number of mid-mass nuclei accessible in an ab initio fashion from a few tens to a few hundred. © 2013 American Physical Society.
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(2012) 'Accuracy of the Faddeev random phase approximation for light atoms'. American Physical Society Physical Review A (Atomic, Molecular and Optical Physics), 85 (1) Article number 012501 Full text is available at: http://epubs.surrey.ac.uk/121081/
Abstract
The accuracy of the Faddeev random phase approximation (FRPA) method is tested by evaluating total and ionization energies in the basis-set limit. A set of light atoms up to Ar is considered. Comparisons are made with the results of coupled-cluster singles and doubles (CCSD), with third-order algebraic diagrammatic construction [ADC(3)], and with the experiment. It is seen that even for two-electron systems, He and Be2+, the inclusion of RPA effects leads to satisfactory results, and therefore it does not overcorrelate the ground state. The FRPA becomes progressively better for larger atomic numbers, where it gives ≈5 mH more correlation energy, and it shifts ionization potentials by 2–10 mH with respect to the similar ADC(3) method. The ionization potentials from FRPA tend to reduce the discrepancies with the experiment.
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(2011) 'Ab initio self-consistent Gorkov-Green's function calculations of semimagic nuclei: Formalism at second order with a two-nucleon'. American Physical Society Physical Review C (Nuclear Physics), 84 (6) Article number 064317 Full text is available at: http://epubs.surrey.ac.uk/121079/
Abstract
An ab initio calculation scheme for finite nuclei based on self-consistent Green's functions in the Gorkov formalism is developed. It aims at describing properties of doubly magic and semimagic nuclei employing state-of-the-art microscopic nuclear interactions and explicitly treating pairing correlations through the breaking of U(1) symmetry associated with particle number conservation. The present paper introduces the formalism necessary to undertake applications at (self-consistent) second order using two-nucleon interactions in a detailed and self-contained fashion. First applications of such a scheme will be reported soon in a forthcoming publication. Future works will extend the present scheme to include three-nucleon interactions and implement more advanced truncation schemes.
- .
(2011) 'Microscopic self-energy calculations and dispersive optical-model potentials'. AMER PHYSICAL SOC PHYSICAL REVIEW C, 84 (3) Article number ARTN 034616 Full text is available at: http://epubs.surrey.ac.uk/26821/
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(2011) 'Nuclear charge radii and electromagnetic moments of radioactive scandium isotopes and isomers'. IOP PUBLISHING LTD JOURNAL OF PHYSICS G-NUCLEAR AND PARTICLE PHYSICS, 38 (2) Article number ARTN 025104 Full text is available at: http://epubs.surrey.ac.uk/7774/
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(2011) 'Faddeev random-phase approximation for molecules'. American Physical Society Physical Review A - Atomic, Molecular, and Optical Physics, 83 (4)Full text is available at: http://epubs.surrey.ac.uk/26822/
- . (2010) 'Knockout of proton-neutron pairs from O-16 with electromagnetic probes'. SPRINGER EUROPEAN PHYSICAL JOURNAL A, 43 (2), pp. 137-143.
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(2009) 'Role of Long-Range Correlations in the Quenching of Spectroscopic Factors'. AMER PHYSICAL SOC PHYSICAL REVIEW LETTERS, 103 (20) Article number ARTN 202502 Full text is available at: http://epubs.surrey.ac.uk/26824/
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(2009) 'Quasiparticle and quasihole states of nuclei around Ni-56'. AMER PHYSICAL SOC PHYSICAL REVIEW C, 79 (6) Article number ARTN 064313 Full text is available at: http://epubs.surrey.ac.uk/26823/
- . (2008) 'Reply to "Comment on 'Pygmy dipole response of proton-rich argon nuclei in random-phase approximation and no-core shell model' "'. AMER PHYSICAL SOC PHYSICAL REVIEW C, 78 (3) Article number ARTN 039802
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(2008) 'Pygmy dipole response of proton-rich argon nuclei in random-phase approximation and no-core shell model'. AMER PHYSICAL SOC PHYSICAL REVIEW C, 77 (2) Article number ARTN 024304 Full text is available at: http://epubs.surrey.ac.uk/26841/
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(2007) 'Quasiparticles in neon using the Faddeev random-phase approximation'. AMER PHYSICAL SOC PHYSICAL REVIEW A, 76 (5) Article number ARTN 052503 Full text is available at: http://epubs.surrey.ac.uk/26848/
- . (2006) 'Single particle spectra based on modem effective interactions'. ELSEVIER SCIENCE BV PHYSICS LETTERS B, 643 (5), pp. 268-272.
- . (2006) 'First measurements of the O-16(e, e ' pn)N-14 reaction (vol 29, pg 261, 2006)'. SPRINGER EUROPEAN PHYSICAL JOURNAL A, 30 (2), pp. 469-469.
- . (2006) 'First measurements of the O-16(e, e ' pn)N-14 reaction'. SPRINGER EUROPEAN PHYSICAL JOURNAL A, 29 (3), pp. 261-270.
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(2005) 'Nucleon-nucleus optical potential in the particle-hole approach'. AMERICAN PHYSICAL SOC PHYSICAL REVIEW C, 72 (1) Article number ARTN 014613 Full text is available at: http://epubs.surrey.ac.uk/27663/
- . (2005) 'Effect of kinematics on final state interactions in (e, e ' p) reactions'. ELSEVIER SCIENCE BV PHYSICS LETTERS B, 608 (1-2), pp. 47-52.
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(2004) 'Effects of rescattering in (e,e ' p) reactions within a semiclassical model'. AMERICAN PHYSICAL SOC PHYSICAL REVIEW C, 70 (5) Article number ARTN 054612 Full text is available at: http://epubs.surrey.ac.uk/27666/
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(2004) 'Effects of nuclear correlations on the O-16(e,e ' pN) reactions to discrete final states'. AMER PHYSICAL SOC PHYSICAL REVIEW C, 70 (1) Article number ARTN 014606 Full text is available at: http://epubs.surrey.ac.uk/27665/
- . (2004) 'Self-consistent Green's function method for nuclei and nuclear matter'. ELSEVIER SCIENCE BV PROGRESS IN PARTICLE AND NUCLEAR PHYSICS, VOL. 52, NO 2, 52 (2), pp. 377-496.
- . (2003) 'Many-body approach to proton emission and the role of spectroscopic factors'. AMERICAN PHYSICAL SOC PHYSICAL REVIEW C, 68 (2) Article number ARTN 024314
- . (2003) 'Extension of the random phase approximation including the self-consistent coupling to two-phonon contributions'. AMERICAN PHYSICAL SOC PHYSICAL REVIEW C, 68 (1) Article number ARTN 014311
- . (2002) 'Faddeev treatment of long-range correlations and the one-hole spectral function of O-16'. AMERICAN PHYSICAL SOC PHYSICAL REVIEW C, 65 (6) Article number ARTN 064313
- . (2001) 'Faddeev description of two-hole-one-particle motion and the single-particle spectral function'. AMERICAN PHYSICAL SOC PHYSICAL REVIEW C, 63 (3) Article number ARTN 034313
Conference papers
- . (2012) 'Self-consistent Gorkov Green's function calculations of one-nucleon spectral properties'. IOP Publishing Journal of Physics: Conference Series, 337 (1)
- . (2011) 'Faddeev Random Phase Approximation for molecules'. Computer Physics Communications, 182 (9), pp. 1995-1998.
- . (2011) 'Gorkov self-consistent Green's function calculations of semi-magic nuclei'. Journal of Physics: Conference Series, 321 (1)
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(2010) 'ONE- AND TWO-NUCLEON STRUCTURE FROM GREEN'S FUNCTION THEORY'. WORLD SCIENTIFIC PUBL CO PTE LTD MODERN PHYSICS LETTERS A, Tokamachi, JAPAN: International Symposium on Forefronts of Researches in Exotic Nuclear Structures 25 (21-23), pp. 1927-1930.Full text is available at: http://epubs.surrey.ac.uk/26838/
Abstract
We review some applications of self-consistent Green's function theory to studies of one- and two-nucleon structure in finite nuclei. Large-scale microscopic calculations that employ realistic nuclear forces are now possible. Effects of long-range correlations are seen to play a dominant role in determining the quenching of absolute spectroscopic factors. They also enhance considerably (e,e'pn) cross sections in superparallel kinematics, in agreement with observations
- . (2010) 'Toward a Global Dispersive Optical Model for the Driplines'. ELSEVIER SCIENCE BV NUCLEAR PHYSICS A, Beijing, PEOPLES R CHINA: 10th International Conference on Nucleus-Nucleus Collisions (NN2009) 834 (1-4), pp. 788C-791C.
- . (2009) 'SPECTROSCOPIC FACTORS IN O-16 AND NUCLEON ASYMMETRY'. WORLD SCIENTIFIC PUBL CO PTE LTD INTERNATIONAL JOURNAL OF MODERN PHYSICS A, Kanto Gakuin Univ, Kannai Media Ctr, Yokohama, JAPAN: KGU Yokohama Autumn School of Nuclear Physics 24 (11), pp. 2060-2068.
- . (2009) 'Ab-initio Green's Functions Calculations of Atoms'. AMER INST PHYSICS PERSPECTIVES IN NUCLEAR PHYSICS, Tokai, JAPAN: 6th Japan-Italy Symposium on Heavy-Ion Physics 1120, pp. 104-108.
- . (2006) 'Final state interactions in electron scattering at high missing energies and momenta'. ELSEVIER SCIENCE BV NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS, Okayama, JAPAN: 4th International Workshop on Neutrino-Nucleus Interactions in the Few-GeV Region 159, pp. 174-179.
- . (2005) 'Self-consistent Green's function calculations of O-16 at small missing energies'. IOP PUBLISHING LTD JOURNAL OF PHYSICS G-NUCLEAR AND PARTICLE PHYSICS, Inst Nucl Theory, Seattle, WA: Workshop on Nuclar Forces and Quantum Many-Body Problem 31 (8), pp. S1301-S1309.
- . (2005) 'Study of the O-16(p,gamma) reaction at astrophysical energies'. ELSEVIER SCIENCE BV NUCLEAR PHYSICS A, Vancouver, CANADA: 8th International Symposium on Nuclei in the Cosmos (NIC8) 758, pp. 395C-398C.
- . (2005) 'Two-step rescattering in (e,e'p) reactions'. European Physical Journal A, 24 (SUPPL. 1), pp. 85-89.
- . (2005) 'Contribution to the wednesday afternoon discussion on spectroscopic factors'. AMER INST PHYSICS Reaction Mechanisms for Rare Isotope Beams, E Lansing, MI: 2nd Argonne/MSU/JINA/INT RIA Workshop 791, pp. 57-60.
