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arXiv · hep-ph/0005225

QCD at finite isospin density

D. T. Son·M. A. Stephanov
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Abstract

QCD at finite isospin chemical potential mu_I has no fermion sign problem and can be studied on the lattice. We solve this theory analytically in two limits: at low mu_I where chiral perturbation theory is applicable, and at asymptotically high mu_I where perturbative QCD works. At low isospin density the ground state is a pion condensate, whereas at high density it is a Fermi liquid with Cooper pairing. The pairs carry the same quantum numbers as the pion. This leads us to a conjecture that the transition from hadron to quark matter is smooth, which passes several tests. Our results imply a nontrivial phase diagram in the space of temperature and chemical potentials of isospin and baryon number.

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D. T. Son, M. A. Stephanov. 2001-01-10. QCD at finite isospin density. https://doi.org/10.1103/physrevlett.86.592

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