New BardeenCooperSchrieffertype theory at finite temperature with particlenumber conservation
Abstract
We formulate a new BardeenCooperSchrieffer (BCS)type theory at finite temperature, by deriving a set of variational equations of the free energy after the particlenumber projection. With its broad applicability, this theory can be a useful tool for investigating the pairing phase transition in finite systems with the particlenumber conservation. This theory provides effects of the symmetryrestoring fluctuation (SRF) for the pairing phenomena in finite fermionic systems, distinctively from those of additional quantum fluctuations. It is shown by numerical calculations that the phase transition is compatible with the conservation in this theory, and that the SRF shifts up the critical temperature (T{sup cr}). This shift of T{sup cr} occurs due to reduction of degreesoffreedom in canonical ensembles, and decreases only slowly as the particlenumber increases (or as the level spacing narrows), in contrast to the conventional BCS theory.
 Authors:
 Department of Physics, Faculty of Science, Chiba University, Inage, Chiba 2638522 (Japan)
 (Japan)
 Publication Date:
 OSTI Identifier:
 20864177
 Resource Type:
 Journal Article
 Resource Relation:
 Journal Name: Physical Review. C, Nuclear Physics; Journal Volume: 74; Journal Issue: 6; Other Information: DOI: 10.1103/PhysRevC.74.061301; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
 Country of Publication:
 United States
 Language:
 English
 Subject:
 73 NUCLEAR PHYSICS AND RADIATION PHYSICS; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; BCS THEORY; CRITICAL TEMPERATURE; DEGREES OF FREEDOM; FERMI GAS; FERMI GAS MODEL; FERMIONS; FLUCTUATIONS; FREE ENERGY; PHASE TRANSFORMATIONS; SYMMETRY; VARIATIONAL METHODS
Citation Formats
Nakada, H., Tanabe, K., and Department of Physics, Faculty of Science, Saitama University, Sakura, Saitama 3388570. New BardeenCooperSchrieffertype theory at finite temperature with particlenumber conservation. United States: N. p., 2006.
Web. doi:10.1103/PHYSREVC.74.061301.
Nakada, H., Tanabe, K., & Department of Physics, Faculty of Science, Saitama University, Sakura, Saitama 3388570. New BardeenCooperSchrieffertype theory at finite temperature with particlenumber conservation. United States. doi:10.1103/PHYSREVC.74.061301.
Nakada, H., Tanabe, K., and Department of Physics, Faculty of Science, Saitama University, Sakura, Saitama 3388570. Fri .
"New BardeenCooperSchrieffertype theory at finite temperature with particlenumber conservation". United States.
doi:10.1103/PHYSREVC.74.061301.
@article{osti_20864177,
title = {New BardeenCooperSchrieffertype theory at finite temperature with particlenumber conservation},
author = {Nakada, H. and Tanabe, K. and Department of Physics, Faculty of Science, Saitama University, Sakura, Saitama 3388570},
abstractNote = {We formulate a new BardeenCooperSchrieffer (BCS)type theory at finite temperature, by deriving a set of variational equations of the free energy after the particlenumber projection. With its broad applicability, this theory can be a useful tool for investigating the pairing phase transition in finite systems with the particlenumber conservation. This theory provides effects of the symmetryrestoring fluctuation (SRF) for the pairing phenomena in finite fermionic systems, distinctively from those of additional quantum fluctuations. It is shown by numerical calculations that the phase transition is compatible with the conservation in this theory, and that the SRF shifts up the critical temperature (T{sup cr}). This shift of T{sup cr} occurs due to reduction of degreesoffreedom in canonical ensembles, and decreases only slowly as the particlenumber increases (or as the level spacing narrows), in contrast to the conventional BCS theory.},
doi = {10.1103/PHYSREVC.74.061301},
journal = {Physical Review. C, Nuclear Physics},
number = 6,
volume = 74,
place = {United States},
year = {Fri Dec 15 00:00:00 EST 2006},
month = {Fri Dec 15 00:00:00 EST 2006}
}

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