Finite-temperature mean-field and higher-order approaches in canonical ensembles

1991 ◽  
Vol 43 (4) ◽  
pp. 1599-1609 ◽  
Author(s):  
R. Rossignoli ◽  
A. Plastino ◽  
H. G. Miller
Keyword(s):  
Finite Temperature ◽  
Mean Field ◽  
Higher Order ◽  
Canonical Ensembles

η-PAIRING SUPERCONDUCTIVITY IN THE NEGATIVE-U HUBBARD MODEL: EFFECT OF FLUCTUATIONS AND DISORDER

1994 ◽  
Vol 08 (15) ◽  
pp. 2041-2058
Author(s):  
JÜRGEN STEIN
Keyword(s):  
Phase Diagram ◽  
Asymptotic Expansion ◽  
Hubbard Model ◽  
Strong Coupling ◽  
Mean Field ◽  
Higher Order ◽  
Field Phase ◽  
Effective Pair ◽  
The Mean ◽  
Pair Hopping

We have studied the influence of singular fluctuations around the mean-field solution as well as higher order contributions to the geometry controlled asymptotic expansion of the propagators on η-pairing superconductivity in the strong coupling negative-U Hubbard model in the presence of unpaired electrons. The modifications of the mean-field results due to the introduction of disorder and allowance for finite U are also calculated. Besides the singularities already present in the O(2) nonlinear σ-model we find a filling-depending singular depression of the repulsive effective pair-hopping interaction which strongly alters the mean-field phase diagram and appears to suppress the η-pairing phase near the band edges.

FINITE TEMPERATURE EQUATIONS OF STATE FOR MIXED STARS

2004 ◽  
Vol 13 (07) ◽  
pp. 1249-1253
Author(s):  
DÉBORA P. MENEZES ◽  
C. PROVIDÊNCIA
Keyword(s):  
Field Theory ◽  
Neutron Stars ◽  
Quark Matter ◽  
Finite Temperature ◽  
Equations Of State ◽  
Mean Field Theory ◽  
Mean Field ◽  
Relativistic Mean Field Theory ◽  
Relativistic Mean Field

We investigate the properties of mixed stars formed by hadronic and quark matter in β-equilibrium described by appropriate equations of state (EOS) in the framework of relativistic mean-field theory. The calculations were performed for T=0 and for finite temperatures and also for fixed entropies with and without neutrino trapping in order to describe neutron and proto-neutron stars. The star properties are discussed. Maximum allowed masses for proto-neutron stars are much larger when neutrino trapping is imposed.

scholarly journals The nonlocal mean-field equation on an interval

2019 ◽  
Vol 22 (05) ◽  
pp. 1950028
Author(s):  
Azahara DelaTorre ◽  
Ali Hyder ◽  
Luca Martinazzi ◽  
Yannick Sire
Keyword(s):  
Field Equation ◽  
Boundary Conditions ◽  
Dirichlet Boundary ◽  
Mean Field ◽  
Higher Order ◽  
Dirichlet Boundary Conditions ◽  
Field Equations ◽  
Mean Field Equations ◽  
Blowing Up ◽  
Mean Field Equation

We consider the fractional mean-field equation on the interval [Formula: see text] [Formula: see text] subject to Dirichlet boundary conditions, and prove that existence holds if and only if [Formula: see text]. This requires the study of blowing-up sequences of solutions. We provide a series of tools in particular which can be used (and extended) to higher-order mean field equations of nonlocal type.

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