Lattice QCD with purely imaginary sources at zero and non-zero temperature

Abstract

We discuss various aspects and recent progress concerning lattice QCD studies in the presence of external sources. We focus, in particular, on issues regarding QCD with non-zero imaginary chemical potentials or with a $\theta$-term, and on the properties of strongly interacting matter in the presence of electromagnetic background fields.

Comments: 15 pages, 2 figures, plenary talk at the 32nd International Symposium on Lattice Field Theory (23-28 June 2014, Columbia University, New York, NY, USA). Minor changes, references added