Critical point and Bose-Einstein condensation in pion matter

We consider a non-ideal hot pion gas with the dynamically fixed number of particles in the model with the λφ4 interaction. The effective Lagrangian for the description of such a system is obtained by dropping the terms responsible for the change of the total particle number. Within the self-consistent Hartree approximation, we compute the effective pion mass, thermodynamic characteristics of the system and identify a critical point of the induced Bose-Einstein condensation when the pion chemical potential reaches the value of the effective pion mass. The normalized variance, skewness, and kurtosis of the particle number distributions are calculated. We demonstrate that all these characteristics remain finite at the critical point of the Bose-Einstein condensation. This is due to the non-perturbative account of the interaction and is in contrast to the ideal-gas case.

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Characteristic Bose-Einstein condensation scaling close to a quantum critical point inBaCuSi2O6

Physical Review B ◽

10.1103/physrevb.72.100404 ◽

2005 ◽

Vol 72 (10) ◽

Cited By ~ 70

Author(s):

S. E. Sebastian ◽

P. A. Sharma ◽

M. Jaime ◽

N. Harrison ◽

V. Correa ◽

...

Keyword(s):

Critical Point ◽

Quantum Critical Point ◽

Einstein Condensation ◽

Bose Einstein Condensation ◽

Quantum Critical ◽

Bose Einstein

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Is FeSe a superconductor in the Bose-Einstein condensation limit?

10.36471/jccm_november_2017_01 ◽

2017 ◽

Keyword(s):

Einstein Condensation ◽

Bose Einstein Condensation ◽

Bose Einstein

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Systems with Condensates and Pairing

10.1093/oso/9780198797241.003.0012 ◽

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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