Quarkonium in quark-gluon plasma: Open quantum system approaches re-examined

Dissociation of quarkonium in quark-gluon plasma (QGP) is a long standing topic in relativistic heavy-ion collisions because it has been believed to signal one of the fundamental natures of the QGP - Debye screening due to the liberation of color degrees of freedom. Among recent new theoretical developments is the application of open quantum system framework to quarkonium in the QGP. Open system approach enables us to describe how dynamical as well as static properties of QGP influences the time evolution of quarkonium in a coherent way. Currently, there are several master equations for quarkonium corresponding to various scale assumptions, each derived in different theoretical frameworks. In this review, all of the existing master equations are systematically rederived as Lindblad equations in a unified framework. Also, as one of the most relevant descriptions in relativistic heavy-ion collisions, quantum Brownian motion of heavy quark pair in the QGP is studied in detail. The quantum Brownian motion is parametrized by a few fundamental quantities of QGP such as real and imaginary parts of heavy quark potential (complex potential), heavy quark momentum diffusion constant, and thermal dipole self-energy constant, which constitute in-medium self-energy of a static quarkonium. This indicates that the yields of quarkonia such as J/psi and Upsilon in the relativistic heavy-ion collisions have the potential to determine these fundamental quantities. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

This review discusses the dissociation of quarkonium and quantum Brownian motion in quark-gluon plasma (QGP), providing a unified framework by systematically rederiving existing master equations as Lindblad equations. It also highlights the potential of quarkonium yields in determining fundamental quantities of QGP.