The CFL phase and m_s: An effective field theory approach

Abstract

We study the phase diagram of dense quark matter with an emphasis on the role of the strange quark mass. Our approach is based on two effective field theories (EFTs). The first is an EFT that describes quark quasi-particles near the Fermi surface. This EFT is valid at energies small compared to the chemical potential. The second is an EFT for the Goldstone modes in the paired phase. We find that in response to a non-zero strange quark mass the CFL phase first undergoes a transition to a kaon condensed phase, and then to a gapless phase with a non-zero Goldstone boson current.

Comments: 26 pages, to appear in ``Pairing in fermionic systems: Basic concepts and modern applications", Series on Advances in Quantum Many-Body Theory, Vol. 8, World Scientific Publishing, Singapore