High density QCD on a Lefschetz thimble? A new approach to the sign problem in QFTs.

by Luigi Scorzato

Wednesday 26 Mar 2014, 15:00 → 16:00 Europe/Rome

248 (Building C, First Floor)

In this talk I illustrate the approach that we recently proposed to perform Monte Carlo simulations of lattice quantum field theories (QFTs) with a sign problem. The approach consists in formulating the theory on a "Lefschetz thimble" (that I will intoduce). The new formulation does not coincide exactly with any of the usual ones, but I argue, relying on universality, that it is also a legitimate regularization. I then describe the algorithm that we are using to smple the configurations on the thimble. The implementation of the algorithm resuires a mapping of the original QFT into a system with one additional dimension. This poses some challenges, but it has favourable expected scaling properties. Finally, I show the results of our first numerical tests on small lattices for a simple but nontrivial QFT. These are very encouraging in view the wide applicability - in principle - of our approach.