Eur. Phys. J. C (2008) 56: 483-492
https://doi.org/10.1140/epjc/s10052-008-0673-8

Regular Article - Theoretical Physics

Chiral susceptibility and chiral phase transition in Nambu–Jona-Lasinio model

¹ Department of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing, 100871, China
² Center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Accelerator, Lanzhou, 730000, China

^* e-mail: yxliu@pku.edu.cn

Received: 5 March 2008
Revised: 29 May 2008
Published online: 9 August 2008

Abstract

We give a general relation between the chiral susceptibility and the thermodynamical potential and a relation between the chiral susceptibility and the condition for furcations to appear in the Wigner solution(s) in the Nambu–Jona-Lasinio (NJL) model. We find that the chiral susceptibility is a quantity able to represent the appearance of furcation in the solution(s) of the gap equation and the concavo–convexity of the thermodynamical potential in the NJL model. It indicates that the chiral susceptibility can identify the stability of the states and the chiral phase transition in NJL model. We propose that analyzing the chiral susceptibility may play an important role in studying the chiral phase transition in approaches superior to the NJL model.