Kondo phase diagram of quark matter

We find a novel type of phase, the Kondo phase, in a quark matter containing heavy quarks as impurities. This phase allows the QCD Kondo effect to occur between a light quark (psi) and a heavy quark (Psi), and is characterized by a nonzero heavy-light condensate <(psi) over bar Psi > which measures the strength of mixing between psi and Psi and represents formation of the Kondo cloud, the ground state composed of light and heavy quarks. Within a field-theoretic approach and mean-field approximation, we obtain the gap equation which self-consistently and non-perturbatively determines the gap Delta similar to <(psi) over bar Psi >. By solving the gap equation with the condition for the heavy-quark number conservation, we draw a phase diagram in mu (the light-quark chemical potential) and lambda (an analog of the heavy-quark chemical potential) plane, and identify the density region of the Kondo phase. (C) 2019 Elsevier B.V. All rights reserved.