Bose-einstein condensation in liquid helium

1958 ◽  
Vol 9 (S1) ◽  
pp. 256-261 ◽  
Author(s):  
O. Penrose
Keyword(s):  
Liquid Helium ◽  
Einstein Condensation ◽  
Bose Einstein Condensation ◽  
Bose Einstein

Bose-Einstein Condensation and Liquid Helium

1956 ◽  
Vol 104 (3) ◽  
pp. 576-584 ◽  
Author(s):  
Oliver Penrose ◽  
Lars Onsager
Keyword(s):  
Liquid Helium ◽  
Einstein Condensation ◽  
Bose Einstein Condensation ◽  
Bose Einstein

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.

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