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Nuclear Theory·nucl-th

Wednesday·January 11, 2017

8 papers—3 primary·5 cross-listed

All8Primary3Cross-lists5
  1. 04

    Complex Langevin dynamics and zeroes of the fermion determinant

    Gert Aarts🇬🇧 · Erhard Seiler🇩🇪 · Denes Sexty🇩🇪 · Ion-Olimpiu Stamatescu🇩🇪

    QCD at nonzero baryon chemical potential suffers from the sign problem, due to the complex quark determinant. Complex Langevin dynamics can provide a solution, provided certain conditions are met. One of these conditions, holomorphicity of the Langevin drift, is absent in QCD since zeroes of the determinant result in a meromorphic drift. We first derive how poles in the drift affect the formal justification of the approach and then explore the various possibilities in simple models. The lessons from these are subsequently applied to both heavy dense QCD and full QCD, and we find that the results obtained show a consistent picture. We conclude that with careful monitoring, the method can be justified a posteriori, even in the presence of meromorphicity.

    ↳ hep-lathep-thnucl-thJHEP(2017)·99 citations
  2. 05

    Euclidean to Minkowski Bethe-Salpeter amplitude and observables

    J. Carbonell🇫🇷 · T. Frederico🇧🇷 · V. A. Karmanov🇷🇺

    We propose a method to reconstruct the Bethe-Salpeter amplitude in Minkowski space given the Euclidean Bethe-Salpeter amplitude -- or alternatively the Light-Front wave function -- as input. The method is based on the numerical inversion of the Nakanishi integral representation and computing the corresponding weight function. This inversion procedure is, in general, rather unstable, and we propose several ways to considerably reduce the instabilities. In terms of the Nakanishi weight function, one can easily compute the BS amplitude, the LF wave function and the electromagnetic form factor. The latter ones are very stable in spite of residual instabilities in the weight function. This procedure allows both, to continue the Euclidean BS solution in the Minkowski space and to obtain a BS amplitude from a LF wave function.

    ↳ hep-phnucl-thEPJC(2017)·9 citations
  3. 06

    pNRQCD determination of E1 radiative transitions

    Sebastian Steinbeißer🇩🇪 · Jorge Segovia🇩🇪

    This contribution contains the first numerical computation of the complete set of relativistic corrections of relative order for electric dipole (E1) transitions in heavy quarkonium; in particular, for the processes with . We assume that the momentum transfer of the heavy mesons involved in the reactions lies in the weak-coupling regime of the low-energy effective field theory potential non-relativistic QCD (pNRQCD) and thus a full perturbative calculation can be performed.

    ↳ hep-phhep-exhep-latnucl-thEPJ Web Conf.(2017)·6 citations
  4. 07

    Effect of strong magnetic field on competing order parameters in two-flavor dense quark matter

    Tanumoy Mandal🇸🇪 · Prashanth Jaikumar🇺🇸

    We study the effect of strong magnetic field on competing chiral and diquark order parameters in a regime of moderately dense quark matter. The inter-dependence of the chiral and diquark condensates through nonperturbative quark mass and strong coupling effects is analyzed in a two-flavor Nambu-Jona-Lasinio (NJL) model. In the weak magnetic field limit, our results agree qualitatively with earlier zero-field studies in the literature that find a critical coupling ratio below which chiral or superconducting order parameters appear almost exclusively. Above the critical ratio, there exists a significant mixed broken phase region where both gaps are non-zero. However, a strong magnetic field G disrupts this mixed broken phase region and changes a smooth crossover found in the weak-field case to a first-order transition for both gaps at almost the same critical density. Our results suggest that in the two-flavor approximation to moderately dense quark matter, strong magnetic field enhances the possibility of a mixed phase at high density, with implications for the structure, energetics and vibrational spectrum of neutron stars.

    ↳ hep-phnucl-thAdv.High Energy Phys.(2017)·12 citations
  5. 08

    Nuclear Structure Studies of Neutron-Rich Nuclei : Astrophysical Implications

    O. Sorlin (GANIL)🇫🇷

    It is proposed here to investigate three major properties of the nuclear force that influence the amplitude of shell gaps, the nuclear binding energies as well as the nuclear -decay properties far from stability, that are all key ingredients for modeling the r-process nucleosynthesis. These properties are derived from experiments performed in different facilities worldwide, using several various state-of-the-art experimental techniques including transfer and knockout reactions. Expected consequences on the r process nucleosynthesis as well as on the stability of super heavy elements are discussed.

    ↳ nucl-exnucl-thJPS Conf.Proc.(2017)·0 citations

Affiliations

first authorsco-authorsvia INSPIRE