Quark self-energy beyond the mean field at finite temperature

1995 ◽  
Vol 51 (4) ◽  
pp. 2256-2259 ◽  
Author(s):  
P. Zhuang
Keyword(s):  
Finite Temperature ◽  
Mean Field ◽  
Self Energy ◽  
The Mean

EFFECTIVE P, T RESTORATION IN CHERN–SIMONS SUPERCONDUCTIVITY

1994 ◽  
Vol 08 (08n09) ◽  
pp. 561-570 ◽  
Author(s):  
S. S. MANDAL ◽  
S. RAMASWAMY ◽  
V. RAVISHANKAR
Keyword(s):  
Dielectric Constant ◽  
Magnetic Susceptibility ◽  
Normal State ◽  
Time Reversal ◽  
Finite Temperature ◽  
Narrow Range ◽  
Mean Field ◽  
Smooth Transition ◽  
The Mean ◽  
Chern Simons

We present an analysis of the finite temperature Chern–Simons superconductivity model within the mean field framework. Using analytical and numerical means we compute the changes in the magnetic susceptibility, conductivity, the dielectric constant, and the specific heat as the temperature is increased. Over a narrow range of temperatures the properties of the system show a smooth transition to the normal state. Accompanying this is the near vanishing of the off-diagonal conductivity, signifying the effective restoration of parity and time reversal symmetries.

QUADRUPOLE DEFORMATION IN NUCLEI AT FINITE TEMPERATURE

1998 ◽  
Vol 13 (33) ◽  
pp. 2705-2713 ◽  
Author(s):  
B. J. COLE ◽  
H. G. MILLER ◽  
R. M. QUICK
Keyword(s):  
Phase Transition ◽  
Finite Temperature ◽  
Mean Field ◽  
Field Approximation ◽  
Quadrupole Deformation ◽  
Mean Field Approximation ◽  
Zero Temperature ◽  
Average Deformation ◽  
The Mean ◽  
Shape Changes

The intrinsic quadrupole deformation has been calculated at finite temperature in 20 Ne both in the mean-field approximation and using an exact shell model diagonalization. The results support the view that the phase transition seen at finite temperature in mean-field calculations is not due to the change in nuclear shape from deformed to spherical, but rather is a collective-to-non-collective transition. Both calculations indicate that the average deformation of 20 Ne changes from β rms ≈0.31 at zero temperature to just over β rms =0.2 at T=3.0 MeV. The calculations also suggest that, in the mean-field approximation, the square of the quadrupole operator, Q[2]·Q[2], is a better indicator of shape changes than Q[2] itself.

APPLICATION OF A NEW VARIATIONAL METHOD TO THE GROSS-NEVEU MODEL

1991 ◽  
Vol 06 (37) ◽  
pp. 3405-3412
Author(s):  
HIROFUMI YAMADA
Keyword(s):  
Variational Method ◽  
Effective Potential ◽  
Finite Temperature ◽  
Mean Field ◽  
Chiral Condensate ◽  
Field Analysis ◽  
Efficient Manner ◽  
The Mean ◽  
Gross Neveu Model

A new variational method proposed by Neveu is applied to the Gross-Neveu model. Chiral condensate is computed perturbatively at zero and finite temperature by the use of effective potential. At both temperatures the expected results in the mean field analysis, nonzero condensate at T=0 and restoration of γ5 symmetry at T≠0, are recovered in an efficient manner by calculating only a few lowest order diagrams.

Self-consistent approximations for field theories at finite temperature

1993 ◽  
Vol 71 (5-6) ◽  
pp. 285-294
Author(s):  
M. H. Thoma
Keyword(s):  
Finite Temperature ◽  
Mean Field ◽  
Field Approximation ◽  
Two Dimensions ◽  
Mean Field Approximation ◽  
Coupling Constant ◽  
Starting Point ◽  
Consistent Approximations ◽  
The Mean ◽  
Mean Field Approximations

Various mean field approximations at finite temperature are used for calculating ground state energies and propagators of the [Formula: see text] theory in two dimensions and quantum chromodynamics (QCD). In the case of the [Formula: see text] theory a symmetry restoration is observed above a critical coupling constant if a temperature independent renormalization is used. In the case of QCD the mean field approximation is insufficient but can be regarded as a starting point for more complicated approximations, which are discussed qualitatively.

THERMAL SHAPE FLUCTUATIONS IN HOT NUCLEI

2004 ◽  
Vol 13 (01) ◽  
pp. 327-331
Author(s):  
V. MARTIN ◽  
J. L. EGIDO ◽  
L. M. ROBLEDO
Keyword(s):  
Phase Transitions ◽  
Finite Temperature ◽  
Mean Field ◽  
Spherical Shape ◽  
Substantial Effect ◽  
Configuration Spaces ◽  
Hartree Fock ◽  
Average Value ◽  
Hot Nuclei ◽  
The Mean

The behavior of several nuclear properties with temperature is analyzed within the framework of the Finite Temperature Hartree-Fock-Bogolyubov (FTHFB) theory with the Gogny force and large configuration spaces. As representative examples the nuclei 164 Er , 152 Dy , 192 Hg and 240 Pu are studied. Numerical results for the deformed to spherical shape phase transitions are presented. Thermal shape fluctuations in the quadrupole degree of freedom, around the mean field solution, are taken into account with the Landau prescription. We found a substantial effect of these fluctuations in the average value of several observables.

GREEN FUNCTIONS IN t-J MODEL OF HIGH-Tc SUPERCONDUCTIVITY

1994 ◽  
Vol 08 (22) ◽  
pp. 3137-3155 ◽  
Author(s):  
VAN HIEU NGUYEN
Keyword(s):  
Real Time ◽  
Finite Temperature ◽  
Mean Field ◽  
Field Approximation ◽  
Mean Field Approximation ◽  
Green Functions ◽  
Imaginary Time ◽  
High Tc ◽  
High Tc Superconductivity ◽  
The Mean

The explicit expressions of the imaginary time normal and anomalous two–point Green functions in the t-J model of high-T c superconductivity without the single occupation constraint as well as those of the real time ones at a finite temperature are derived in the mean field approximation. The possible applications of these results are outlined.

Classical Kinetic Theory

2018 ◽  
Author(s):  
Klaus Morawetz
Keyword(s):  
Kinetic Equation ◽  
Equation Of State ◽  
Mean Field ◽  
Ideal Gas ◽  
Hydrodynamic Equations ◽  
Free Particles ◽  
Internal Mechanism ◽  
The Mean ◽  
Energy Gains ◽  
Non Locality

The classical non-ideal gas shows that the two original concepts of the pressure based of the motion and the forces have eventually developed into drift and dissipation contributions. Collisions of realistic particles are nonlocal and non-instant. A collision delay characterizes the effective duration of collisions, and three displacements, describe its effective non-locality. Consequently, the scattering integral of kinetic equation is nonlocal and non-instant. The non-instant and nonlocal corrections to the scattering integral directly result in the virial corrections to the equation of state. The interaction of particles via long-range potential tails is approximated by a mean field which acts as an external field. The effect of the mean field on free particles is covered by the momentum drift. The effect of the mean field on the colliding pairs causes the momentum and the energy gains which enter the scattering integral and lead to an internal mechanism of energy conversion. The entropy production is shown and the nonequilibrium hydrodynamic equations are derived. Two concepts of quasiparticle, the spectral and the variational one, are explored with the help of the virial of forces.

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