What hard probes tell us about the quark–gluon plasma: Theory

In the study of quark–gluon plasma in high-energy heavy-ion collisions, hard and electromagnetic (EM) processes can be used to probe a wide range of properties of the hot and dense medium, from space–time profiles of the bulk matter, bulk transport coefficients to EM responses and the jet transport parameter. These medium properties, how they can be studied through hard and EM probes and the status of recent theoretical and phenomenological investigations are reviewed in this talk.