A phase diagram for the Bose-Einstein condensation of magnons

2007 ◽  
Vol 101 (9) ◽  
pp. 09G103 ◽  
Author(s):  
L. H. Bennett ◽  
E. Della Torre ◽  
P. R. Johnson ◽  
R. E. Watson
Keyword(s):  
Phase Diagram ◽  
Einstein Condensation ◽  
Bose Einstein Condensation ◽  
Bose Einstein

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.

ELECTRONICALLY DRIVEN FERROELECTRICITY IN THE EXTENDED FALICOV-KIMBALL MODEL

2005 ◽  
Vol 19 (01n03) ◽  
pp. 525-527
Author(s):  
J. BONČA ◽  
C. D. BATISTA ◽  
J. E. GUBERNATIS ◽  
H. Q. LIN
Keyword(s):  
Phase Diagram ◽  
Monte Carlo ◽  
Quantum Monte Carlo ◽  
Mixed Valence ◽  
Electric Polarization ◽  
Monte Carlo Technique ◽  
Einstein Condensation ◽  
Intermediate Coupling ◽  
Bose Einstein Condensation ◽  
Bose Einstein

We calculate the quantum phase diagram of an extended Falicov-Kimball model in the intermediate coupling regime using a constrained path quantum Monte Carlo technique. The mixed-valence regime is dominated by a Bose-Einstein condensation of excitons with a built-in electric polarization.

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.

Systems with Condensates and Pairing

2018 ◽  
Author(s):  
Klaus Morawetz
Keyword(s):  
Critical Parameters ◽  
Einstein Condensation ◽  
Cooper Pairs ◽  
Pair Breaking ◽  
Systematic Theory ◽  
Bose Einstein Condensation ◽  
T Matrix ◽  
The Stability ◽  
Bose Einstein

The Bose–Einstein condensation and appearance of superfluidity and superconductivity are introduced from basic phenomena. A systematic theory based on the asymmetric expansion of chapter 11 is shown to correct the T-matrix from unphysical multiple-scattering events. The resulting generalised Soven scheme provides the Beliaev equations for Boson’s and the Nambu–Gorkov equations for fermions without the usage of anomalous and non-conserving propagators. This systematic theory allows calculating the fluctuations above and below the critical parameters. Gap equations and Bogoliubov–DeGennes equations are derived from this theory. Interacting Bose systems with finite temperatures are discussed with successively better approximations ranging from Bogoliubov and Popov up to corrected T-matrices. For superconductivity, the asymmetric theory leading to the corrected T-matrix allows for establishing the stability of the condensate and decides correctly about the pair-breaking mechanisms in contrast to conventional approaches. The relation between the correlated density from nonlocal kinetic theory and the density of Cooper pairs is shown.

scholarly journals Bose Einstein condensation in a magnetic double-well potential

2003 ◽  
Vol 5 (2) ◽  
pp. S119-S123 ◽  
Author(s):  
T G Tiecke ◽  
M Kemmann ◽  
Ch Buggle ◽  
I Shvarchuck ◽  
W von Klitzing ◽  
...  
Keyword(s):  
Einstein Condensation ◽  
Bose Einstein Condensation ◽  
Bose Einstein ◽  
Double Well Potential
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