BECBCS crossover in the NambuJonaLasinio model of QCD
Abstract
The BECBCS (BoseEinstein condensationBardeenCooperShriffer) crossover in QCD at finite baryon and isospin chemical potentials is investigated in the NambuJonaLasinio model. The diquark condensation in two color QCD and the pion condensation in real QCD would undergo a BECBCS crossover when the corresponding chemical potential increases. We determined the crossover chemical potential as well as the BEC and BCS regions. The crossover is not triggered by increasing the strength of attractive interaction among quarks but driven by changing the charge density. The chiral symmetry restoration at finite temperature and density plays an important role in the BECBCS crossover. For real QCD, strong couplings in diquark and vector meson channels can induce a diquark BECBCS crossover in color superconductor, and in the BEC region the chromomagnetic instability is fully cured and the ground state is a uniform phase.
 Authors:
 Physics Department, Tsinghua University, Beijing 100084 (China)
 Publication Date:
 OSTI Identifier:
 21020517
 Resource Type:
 Journal Article
 Resource Relation:
 Journal Name: Physical Review. D, Particles Fields; Journal Volume: 75; Journal Issue: 9; Other Information: DOI: 10.1103/PhysRevD.75.096004; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
 Country of Publication:
 United States
 Language:
 English
 Subject:
 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; BARYONS; BCS THEORY; BOSEEINSTEIN CONDENSATION; CHARGE DENSITY; CHIRAL SYMMETRY; COLOR MODEL; GROUND STATES; ISOSPIN; PION CONDENSATION; POTENTIALS; QUANTUM CHROMODYNAMICS; QUARKS; SUPERCONDUCTORS; VECTOR MESONS
Citation Formats
Sun Gaofeng, He Lianyi, and Zhuang Pengfei. BECBCS crossover in the NambuJonaLasinio model of QCD. United States: N. p., 2007.
Web. doi:10.1103/PHYSREVD.75.096004.
Sun Gaofeng, He Lianyi, & Zhuang Pengfei. BECBCS crossover in the NambuJonaLasinio model of QCD. United States. doi:10.1103/PHYSREVD.75.096004.
Sun Gaofeng, He Lianyi, and Zhuang Pengfei. Tue .
"BECBCS crossover in the NambuJonaLasinio model of QCD". United States.
doi:10.1103/PHYSREVD.75.096004.
@article{osti_21020517,
title = {BECBCS crossover in the NambuJonaLasinio model of QCD},
author = {Sun Gaofeng and He Lianyi and Zhuang Pengfei},
abstractNote = {The BECBCS (BoseEinstein condensationBardeenCooperShriffer) crossover in QCD at finite baryon and isospin chemical potentials is investigated in the NambuJonaLasinio model. The diquark condensation in two color QCD and the pion condensation in real QCD would undergo a BECBCS crossover when the corresponding chemical potential increases. We determined the crossover chemical potential as well as the BEC and BCS regions. The crossover is not triggered by increasing the strength of attractive interaction among quarks but driven by changing the charge density. The chiral symmetry restoration at finite temperature and density plays an important role in the BECBCS crossover. For real QCD, strong couplings in diquark and vector meson channels can induce a diquark BECBCS crossover in color superconductor, and in the BEC region the chromomagnetic instability is fully cured and the ground state is a uniform phase.},
doi = {10.1103/PHYSREVD.75.096004},
journal = {Physical Review. D, Particles Fields},
number = 9,
volume = 75,
place = {United States},
year = {Tue May 01 00:00:00 EDT 2007},
month = {Tue May 01 00:00:00 EDT 2007}
}

QCDlike theories possess a positively definite fermion determinant at finite baryon chemical potential {mu}{sub B} and the lattice simulation can be successfully performed. While the chiral perturbation theories are sufficient to describe the Bose condensate at low density, to describe the crossover from BoseEinstein condensation (BEC) to BCS superfluidity at moderate density we should use some fermionic effective model of QCD, such as the NambuJonaLasinio model. In this paper, using twocolor twoflavor QCD as an example, we examine how the NambuJonaLasinio model describes the weakly interacting Bose condensate at low density and the BECBCS crossover at moderate density. Near themore »

NambuJonaLasinio model of dense threeflavor matter with axial anomaly: The low temperature critical point and BECBCS diquark crossover
We study the QCD phase structure in the threeflavor NambuJonaLasinio model, incorporating the interplay between the chiral and diquark condensates induced by the axial anomaly. We demonstrate that for an appropriate range of parameters of the model, the interplay leads to the low temperature critical point in the phase structure predicted by a previous GinzburgLandau analysis. We also show that a BoseEinstein condensate (BEC) of diquark molecules emerges in the intermediate density region, and as a result, a BECBCS crossover is realized with increasing quark chemical potential. 
Chiral crossover, deconfinement, and quarkyonic matter within a NambuJonaLasinio model with the Polyakov loop
We study the interplay between the chiral and the deconfinement transitions, both at high temperature and high quark chemical potential, by a nonlocal NambuJonaLasinio model with the Polyakov loop in the mean field approximation and requiring neutrality of the ground state. We consider three forms of the effective potential of the Polyakov loop: two of them with a fixed deconfinement scale, cases I and II, and the third one with a {mu} dependent scale, case III. In cases I and II, at high chemical potential {mu} and low temperature T, the main contribution to the free energy is due tomore » 
Extended Nambu{endash}JonaLasinio model and hidden local symmetry of low energy QCD
Using the standard auxiliary field method, we derive from the extended Nambu{endash}JonaLasinio model an effective meson action containing vector and axialvector mesons in addition to Goldstone bosons. The vector and axialvector mesons in this effective action transform as gauge fields of hidden local symmetry {ital G}{sub local}=[U({ital n}){sub {ital L}}{times}U({ital n}){sub {ital R}}]{sub local}. Here, the realization of enlarged hidden local symmetry is accomplished via the introduction of two kinds of {open_quote}{open_quote}compensating{close_quote}{close_quote} fields. For obtaining the intrinsicparityviolating part of the action, we generalize the standard gauged WessZuminoWitten action such that it also contains two kinds of {open_quote}{open_quote}compensators{close_quote}{close_quote} in addition tomore »