Confronting analytic continuation from imaginary to real chemical potential in Lattice QCD

Lattice QCD simulations at finite density are severely plagued by the infamous sign problem. Two main workarounds are available: one can either compute Taylor expansions of observables at zero (baryonic) chemical potential or compute observables at imaginary values of the latter. While the first method is per se an analytic continuation from zero chemical potential, in the second case one has to explicitly perform an analytic continuation from the imaginary to the real axis in the complex chemical potential plane. Here we are mainly concerned with a couple of methods, both stemming from sort of joining the two methods: a certain form of Padè approximants and an application of the Cauchy formula in the form of an inverse problem.