scholarly journals Phase Transitions and Bose–Einstein Condensation in Alpha-Nucleon Matter

2019 ◽  
Vol 64 (8) ◽  
pp. 745
Author(s):  
L. M. Satarov ◽  
I. N. Mishustin ◽  
A. Motornenko ◽  
V. Vovchenko ◽  
M. I. Gorenstein ◽  
...  
Keyword(s):  
Phase Diagram ◽  
Phase Transitions ◽  
Mean Field ◽  
Field Approximation ◽  
Mean Field Approximation ◽  
Einstein Condensation ◽  
Bose Einstein Condensation ◽  
Nucleon Matter ◽  
Bose Einstein ◽  
First Order Phase

The equation of state and the phase diagram of an isospin-symmetric chemically equilibrated mixture of a particles and nucleons (N) are studied in the mean-field approximation. We use a Skyrme-like parametrization of mean-field potentials as functions of the partial densities of particles. The parameters of these potentials are chosen by fitting the known properties of pure N- and pure a-matters at zero temperature. The sensitivity of results to the choice of the aN attraction strength is investigated. The phase diagram of the a − N mixture is studied with a special attention paid to the liquid-gas phase transitions and the Bose–Einstein condensation of a particles. We have found two first-order phase transitions, stable and metastable, which differ significantly by the fractions of a’s. It is shown that the states with a condensate are metastable.

Partially Disordered State in the Frustrated Heisenberg Ferrimagnet

2014 ◽  
Vol 215 ◽  
pp. 55-60 ◽  
Author(s):  
Sergey N. Martynov
Keyword(s):  
Phase Diagram ◽  
Phase Transitions ◽  
Magnetic Phase ◽  
Mean Field ◽  
Exchange Interactions ◽  
Field Approximation ◽  
Magnetic Phase Transitions ◽  
Mean Field Approximation ◽  
The Mean ◽  
Competition Parameter

A model for the description of two-subsystem Heisenberg ferrimagnet with frustrated intersubsystem exchange and competition between exchange interactions in a subsystem is proposed. The conditions of the existence of noncollinear Yafet-Kittel state and partially ordered magnetic structure are investigated. The phase diagram of competition parameter vs temperature is obtained in the mean field approximation. The peculiarities of the succesive magnetic phase transitions are considered.

A MEAN FIELD STUDY OF THE PHASE TRANSITIONS IN A CLASS OF SYSTEMS WITH COMPLEX ORDER PARAMETERS

1994 ◽  
Vol 08 (28) ◽  
pp. 3963-3986
Author(s):  
EVGENIA J. BLAGOEVA
Keyword(s):  
Phase Diagram ◽  
Phase Transitions ◽  
Order Parameter ◽  
Mean Field ◽  
Field Approximation ◽  
Mean Field Approximation ◽  
Unconventional Superconductors ◽  
Complex Order ◽  
The Mean ◽  
Expansion Coefficients

A generalized Landau free energy for a complex order parameter expanded up to sixth-order is investigated using group theoretical arguments and the mean-field approximation. Results for the phase transitions that occur are presented. The phase diagram for all allowed values of the expansion coefficients is constructed with an emphasis placed on the influence of the anisotropy in the order parameter space. The results can be used in discussions of unconventional superconductors and modulated structural and magnetic orderings.

scholarly journals TIME-DEPENDENT VARIATIONAL APPROACH TO BOSE–EINSTEIN CONDENSATION

2000 ◽  
Vol 14 (01) ◽  
pp. 1-11 ◽  
Author(s):  
LUCA SALASNICH
Keyword(s):  
Variational Approach ◽  
Mean Field ◽  
Field Approximation ◽  
Einstein Condensate ◽  
Time Dependent ◽  
Mean Field Approximation ◽  
Einstein Condensation ◽  
Collective Oscillations ◽  
The Stability ◽  
Bose Einstein

We discuss the mean-field approximation for a trapped weakly-interacting Bose–Einstein condensate (BEC) and its connection with the exact many-body problem by deriving the Gross–Pitaevskii action of the condensate. The mechanics of the BEC in a harmonic potential is studied by using a variational approach with time-dependent Gaussian trial wave-functions. In particular, we analyze the static configurations, the stability and the collective oscillations for both ground-state and vortices.

scholarly journals Phase transitions and Bose-Einstein condensation in α -nucleon matter

2019 ◽  
Vol 99 (2) ◽  
Author(s):  
L. M. Satarov ◽  
I. N. Mishustin ◽  
A. Motornenko ◽  
V. Vovchenko ◽  
M. I. Gorenstein ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Einstein Condensation ◽  
Bose Einstein Condensation ◽  
Nucleon Matter ◽  
Bose Einstein

QCD susceptibilities in the presence of the chiral chemical potential

2020 ◽  
Vol 35 (16) ◽  
pp. 2050137
Author(s):  
Run-Lin Liu ◽  
Hong-Shi Zong
Keyword(s):  
Phase Transition ◽  
Phase Diagram ◽  
Chemical Potential ◽  
Mean Field ◽  
Field Approximation ◽  
Mean Field Approximation ◽  
Chiral Phase ◽  
First Order Phase Transition ◽  
Phase Transition Region ◽  
First Order Phase

In this paper, chiral chemical potential [Formula: see text] is introduced to investigate the QCD susceptibilities and chiral phase transition within the Polyakov-loop-extended Nambu–Jona-Lasinio models in the mean-field approximation. We concentrate on the effect of chiral chemical potential on the phase diagram and the QCD susceptibilities. Moreover, it is worth noting that chiral chemical potential has more and more prominent impact on the susceptibilities and the phase diagram with the decrease of temperature based on our results, which coincides with the prediction that the chiral symmetry is dynamically broken in the first-order phase transition region and gets partly restored in the crossover region.

SURFACE PHASE DIAGRAMS OF SEMI-INFINITE FERRIMAGNETIC SYSTEM

2021 ◽  
pp. 2150025
Author(s):  
SAIDA ZOUHAIR ◽  
MOHAMED MONKADE ◽  
ABDELMOUMEN EL ANTARI ◽  
MOHAMMED EL BOUZIANI ◽  
NABIL HACHEM ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Phase Diagrams ◽  
Mean Field ◽  
Three Dimensional ◽  
Exchange Interactions ◽  
Field Approximation ◽  
Mean Field Approximation ◽  
Surface Exchange ◽  
Crystal Fields ◽  
First Order Phase

The three-dimensional semi-infinite mixed spin-1/2 and spin-3/2 ferrimagnetic Ising system with crystal field is investigated using the mean-field approximation and the Monte Carlo simulation. According to the ratio [Formula: see text] of bulk and surface exchange interactions and the ratio [Formula: see text] of bulk and surface crystal fields, we have classified four qualitative types of phase diagrams characterized by the presence or absence of ordinary, extraordinary, surface and special phase transitions. The critical behavior of the surface and bulk magnetizations has also been highlighted in the vicinity of these different transitions. At low temperatures, two critical end-points appear in the bulk and on the surface in the ordered region limiting two successive first-order phase transitions. Furthermore, we have made a comparison with other works on similar models in pure or mixed versions.

scholarly journals What is strange about high-temperature superconductivity in cuprates?

2017 ◽  
Vol 31 (25) ◽  
pp. 1745005
Author(s):  
I. Božović ◽  
X. He ◽  
J. Wu ◽  
A. T. Bollinger
Keyword(s):  
Phase Diagram ◽  
Cuprate Superconductors ◽  
High Temperature Superconductivity ◽  
Einstein Condensation ◽  
Strongly Correlated ◽  
Bose Einstein Condensation ◽  
Ultimate Question ◽  
Underdoped Cuprates ◽  
Bose Einstein ◽  
Superconducting Parameters

Cuprate superconductors exhibit many features, but the ultimate question is why the critical temperature ([Formula: see text]) is so high. The fundamental dichotomy is between the weak-pairing, Bardeen–Cooper–Schrieffer (BCS) scenario, and Bose–Einstein condensation (BEC) of strongly-bound pairs. While for underdoped cuprates it is hotly debated which of these pictures is appropriate, it is commonly believed that on the overdoped side strongly-correlated fermion physics evolves smoothly into the conventional BCS behavior. Here, we test this dogma by studying the dependence of key superconducting parameters on doping, temperature, and external fields, in thousands of cuprate samples. The findings do not conform to BCS predictions anywhere in the phase diagram.

A MODEL OF BOSE–EINSTEIN CONDENSATION WITH ITINERANT AND LOCALIZED STATES

2005 ◽  
Vol 19 (21) ◽  
pp. 1011-1034
Author(s):  
FUXIANG HAN ◽  
ZHIRU REN ◽  
YUN'E GAO
Keyword(s):  
Critical Temperature ◽  
Anderson Model ◽  
Localized States ◽  
Mean Field Approximation ◽  
Einstein Condensation ◽  
Model Parameters ◽  
Zeroth Order ◽  
Energy Bands ◽  
Bose Einstein Condensation ◽  
Bose Einstein

We propose a model that includes itinerant and localized states to study Bose–Einstein condensation of ultracold atoms in optical lattices (Bose–Anderson model). It is found that the original itinerant and localized states intermix to give rise to a new energy band structure with two quasiparticle energy bands. We have computed the critical temperature Tc of the Bose–Einstein condensation of the quasiparticles in the Bose–Anderson model using our newly developed numerical algorithm and found that Tc increases as na3 (the number density times the lattice constant cubed) increases according to the power law Tc≈18.93(na3)0.59 nK for na3<0.125 and according to the linear relation Tc≈8.75+10.53na3 nK for 1.25<na3<12.5 for the given model parameters. With the self-consistent equations for the condensation fractions obtained within the Bogoliubov mean-field approximation, the effects of the on-site repulsion U on the quasiparticle condensation are investigated. We have found that, for values up to several times the zeroth-order critical temperature, U enhances the zeroth-order condensation fraction at intermediate temperatures and effectively raises the critical temperature, while it slightly suppresses the zeroth-order condensation fraction at very low temperatures.

Sign in / Sign up

Export Citation Format

Share Document