2019/11/14 by Gaoqing Cao, Lianyi He · 1 citation
Physics and Astronomy · #High-Energy Particle Collisions Research #Quantum Chromodynamics and Particle Interactions #Particle physics theoretical and experimental studies
paper · doi:10.1103/physrevd.100.094015
We investigate the possibility of charged pion condensation in the presence of parallel rotation and magnetic field within the Nambu--Jona-Lasinio model with quarks as the fundamental degrees of freedom. Previous study based on noninteracting Klein-Gordon theory for pions showed that the charged pions will undergo Bose-Einstein condensation under this circumstance [Y. Liu and I. Zahed, Phys. Rev. Lett. 120, 032001 (2018).]. In this work, we take into account the internal quark structures of charged pions self-consistently through quark polarization loops in an interacting theory, i.e., the Nambu--Jona-Lasino model. The stability of the system against the formation of charged pion condensation, i.e., a nonzero expectation value of the composite charged pion field ui\ensuremathγ5d, is explored. We find that two competing effects are induced by the rotation: the isospin enhancement which favors charged pion condensation and the spin breaking which disfavors the condensation. For a strong magnetic field (√(eB)\ensuremath∼1 GeV) and system size of a few fermi, the isospin enhancement effect is stronger than the spin breaking one, and the charged pion condensation becomes energetically favored beyond a critical angular velocity of a few MeV.