19,987 research outputs found
Number-conserving theory of nuclear pairing gaps: a global assessment
We study odd-even mass staggering of nuclei, also called pairing gaps, using
a Skyrme self-consistent mean-field theory and a numerically exact treatment of
the pairing Hamiltonian. We find that the configuration-space Monte Carlo
method proposed by Cerf and Martin offers a practical computational procedure
to carry out the numerical solutions in large-dimensional model spaces.
Refitting the global strength of the pairing interaction for 443 neutron
pairing gaps in our number-conserving treatment, we find the correction to the
pairing correlation energies and pairing gaps to have rms values of 0.6 MeV and
0.12 MeV, respectively. The exact treatment provides a significant improvement
in the fit to experimental gaps, although it is partially masked by a larger
rms error due to deficiencies in other aspects of the theory such as the
mean-field energy functional.Comment: 11 pages, 9 figure
Agterberg, Zheng, and Mukherjee Reply
Reply to Ikeda (arXiv:0712.3341).Comment: To appear in Phys. Rev. Let
Signatures of charmonium modification in spatial correlation functions
We study spatial correlation functions of charmonium in 2+1 flavor QCD using
an improved staggered formulation. Contrary to the temporal correlation
functions the spatial correlation functions exhibit a strong temperature
dependence above the QCD transition temperature. Above this temperature they
are sensitive to temporal boundary conditions. Both features become significant
at a temperature close to 1.5 Tc and suggest corresponding modifications of
charmonium spectral functions.Comment: 12 pages, LaTeX, 3 figure
Eigenvalue distribution of the Dirac operator at finite temperature with (2+1)-flavor dynamical quarks using the HISQ action
We report on the behavior of the eigenvalue distribution of the Dirac
operator in (2+1)-flavor QCD at finite temperature, using the HISQ action. We
calculate the eigenvalue density at several values of the temperature close to
the pseudocritical temperature. For this study we use gauge field
configurations generated on lattices of size with two light
quark masses corresponding to pion masses of about 160 and 115 MeV. We find
that the eigenvalue density below receives large contributions from
near-zero modes which become smaller as the temperature increases or the light
quark mass decreases. Moreover we find no clear evidence for a gap in the
eigenvalue density up to 1.1. We also analyze the eigenvalue density near
where it appears to show a power-law behavior consistent with what is
expected in the critical region near the second order chiral symmetry restoring
phase transition in the massless limit.Comment: 7 pages, 7 figures, talk presented at the XXIX International
Symposium on Lattice Field Theory, July 10-16 2011, Squaw Valley, Lake Tahoe,
California, US
Quantum field theories on the Lefschetz thimble
In these proceedings, we summarize the Lefschetz thimble approach to the sign
problem of Quantum Field Theories. In particular, we review its motivations,
and we summarize the results of the application of two different algorithms to
two test models.Comment: contributions to 31st International Symposium on Lattice Field Theory
- LATTICE 2013, July 29 - August 3, 2013, Mainz, Germany and QCD-TNT-III, 2-6
September, 2013, European Centre for Theoretical Studies in Nuclear Physics
and Related Areas (ECT*), Villazzano, Trento (Italy
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