Static linear response of hot and dense QCD matter to electromagnetic fields: leading hard and soft QCD corrections

A bstract We compute the static electromagnetic susceptibilities of a hot and dense quark-gluon plasma using perturbative Quantum Chromodynamics (QCD). Our evaluation includes the leading 𝒪( α s ) correction as well as the leading soft, resummed contribution of O(αₛ3/2) O α s 3 / 2 within electrostatic QCD. By matching to Lattice QCD at vanishing baryon chemical potential through Lattice perturbation theory, we establish a connection between perturbative results and Lattice simulations and assess the size of higher-order corrections. This extends the electromagnetic susceptibilities to finite baryon chemical potential, where Lattice methods are not applicable and establishes first-principle constraints on the quark-gluon plasma’s electromagnetic response at temperatures and densities relevant for intermediate-energy heavy-ion collisions.