2019/01/22 by Luca Lepori, L. Lepori, Massimo Mannarelli · 3 citations
Physics and Astronomy · #Chiral perturbation theory #Chiral symmetry #Chiral symmetry breaking #Cold Atom Physics and Bose-Einstein Condensates #Instability #Isospin #Meson #Particle physics #Perturbation (astronomy) #Perturbation theory (quantum mechanics) #Physics #Pion #Quantum Chromodynamics and Particle Interactions #Quantum chromodynamics #Quantum electrodynamics #Quantum mechanics #Quantum, superfluid, helium dynamics #Superfluidity #Symmetry breaking #cond-mat.quant-gas #cond-mat.str-el #cond-mat.supr-con #hep-ph
paper · pdf · doi:10.1103/physrevd.99.096011
published as Phys. Rev. D 99, 096011 (2019) · 13 pages, 5 figures
arxiv created 2019/01/22 · openalex publication_date 2019/05/14 · arxiv updated 2019/05/22 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We show that multicomponent meson systems can be described by chiral perturbation theory. We chiefly focus on a system of two pion gases at different isospin chemical potential, deriving the general expression of the chiral Lagrangian, the ground state properties and the spectrum of the low-energy excitations. We consider two different kinds of interactions between the two meson gases: one which does not lock the two chiral symmetry groups and one which does lock them. The former is a kind of interaction that has already been discussed in multicomponent superfluids. The latter is perhaps more interesting, because it seems to be related to an instability. Although the pressure of the system does not show any instability, we find that for sufficiently strong locking, the spectrum of one Bogolyubov mode becomes tachyonic. This unstable branch seems to indicate a transition to an inhomogeneous phase.