Bose–Einstein Condensation of Collective Electron Pairs

2013 ◽  
Vol 175 (1-2) ◽  
pp. 295-304 ◽  
Author(s):  
Carlos Ramírez ◽  
Chumin Wang
Keyword(s):  
Einstein Condensation ◽  
Electron Pairs ◽  
Bose Einstein Condensation ◽  
Bose Einstein

FIVE POSSIBLE REASONS WHY HIGH-Tc SUPERCONDUCTIVITY IS STALLED

2007 ◽  
Vol 21 (13n14) ◽  
pp. 2313-2323
Author(s):  
M. GRETHER ◽  
M. DE LLANO
Keyword(s):  
Microscopic Theory ◽  
Bcs Theory ◽  
Einstein Condensation ◽  
Critical Temperatures ◽  
Electron Pairs ◽  
High Tc ◽  
Bose Einstein Condensation ◽  
Phonon Mechanism ◽  
Bose Einstein ◽  
Theory Of Superconductivity

Five commonly held premises considered questionable assumptions in the microscopic theory of superconductivity are discussed as possible reasons why the search appears to be stalled for a theoretical framework, admittedly ambitious, capable of predicting materials with critical temperatures Tc higher than the 1993 record of 164K in HgTlBaCaCuO (under pressure). We focus the dilemma as a whole in terms of a generalized Bose-Einstein condensation (GBEC) interpretation that includes and further extends BCS theory, as well as substantially enhancing its predicted Tcs within the electron-phonon mechanism producing pairing. The new GBEC model is an extension of the Friedberg-T.D. Lee 1989 boson-fermion BEC theory of high-Tc superconductors in that it includes hole pairs as well as electron pairs.

scholarly journals TOWARDS BOSE–EINSTEIN CONDENSATION OF ELECTRON PAIRS: ROLE OF SCHWINGER BOSONS

1999 ◽  
Vol 13 (08) ◽  
pp. 925-937 ◽  
Author(s):  
GANG SU ◽  
MASUO SUZUKI
Keyword(s):  
Hilbert Space ◽  
Hubbard Model ◽  
Strong Coupling ◽  
Einstein Condensation ◽  
Electron Pairs ◽  
Bose Einstein Condensation ◽  
Attractive Hubbard Model ◽  
Hilbert Subspace ◽  
Bose Einstein

It can be shown that the bosonic degree of freedom of the tightly bound on-site electron pairs could be separated as Schwinger bosons. This is implemented by projecting the whole Hilbert space into the Hilbert subspace spanned by states of two kinds of Schwinger bosons (to be called binon and vacanon) subject to a constraint that these two kinds of bosonic quasiparticles cannot occupy the same site. We argue that a binon is actually a kind of quantum fluctuations of electron pairs, and a vacanon corresponds to a vacant state. These two bosonic quasiparticles may be responsible for the Bose–Einstein condensation (BEC) of the system associated with electron pairs. These concepts are also applied to the attractive Hubbard model with strong coupling, showing that it is quite useful. The relevance of the present arguments to the existing theories associated with the BEC of electron pairs is briefly commented.

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

Bose-Einstein condensation of large numbers of atoms in a magnetic time-averaged orbiting potential trap

1998 ◽  
Vol 57 (6) ◽  
pp. R4114-R4117 ◽  
Author(s):  
D. J. Han ◽  
R. H. Wynar ◽  
Ph. Courteille ◽  
D. J. Heinzen
Keyword(s):  
Einstein Condensation ◽  
Bose Einstein Condensation ◽  
Large Numbers ◽  
Potential Trap ◽  
Bose Einstein
Sign in / Sign up

Export Citation Format

Share Document