ABSTRACT: For decades, heavy quarks and their bound states have served as ideal experimental and theoretical probes of the medium formed in heavy ion collisions. Specifically, suppression of heavy-heavy bound states in heavy ion relative to proton-proton collisions was postulated as a strong signal of
the formation of a deconfined quark gluon plasma. More recently, the use of effective field theories (EFTs), allowing for the systematic exploitation of hierarchies of scale in a physical system, and the formalism of open quantum systems (OQS), allowing for a quantum mechanically rigorous description of a system evolving coupled to and out of equilibrium with an environment, has led to great advances in first principles descriptions of in-medium heavy-heavy bound states. In this talk, I will present the derivation of a master equation in the EFT+OQS framework and emphasize recent theoretical work enabling simulation of in-medium states down to temperatures approaching
the QCD phase transition and the use of improved potentials leading to more accurate bound state spectra. I will then discuss methods of solution of the master equation and the calculation of observables and compare our calculations of the nuclear modification factor of the Υ(1S), Υ(2S)
and Υ(3S) states against measurements by the ALICE, ATLAS and CMS collaborations.