The magnetic susceptibility in QCD

Abstract

Recently much work has been devoted to the study of QCD coupled to a background magnetic field. Strongly interacting matter acts as a magnetic medium and it is natural to study the properties of this medium, in particular to understand if it behaves like a diamagnetic or a paramagnetic material. A serious difficulty in studying these properties by means of LQCD simulations is the quantization of the magnetic field in a toroidal geometry. We will expose a method to overcome this difficulty and we will present data obtained for the $N_f=2$ theory that show that the QCD medium is paramagnetic.

7 pages, talk presented at the 31st International Symposium on Lattice Field Theory - Lattice 2013, Mainz, Germany