[Hybrid RBRC seminar] Mitigating noise in Green's function Monte Carlo using contour deformations

by Gurtej Kanwar (University of Bern)

Thursday 8 Jun 2023, 12:30 → 13:30 US/Eastern

2-160 (https://bnl.zoomgov.com/j/1606067399?pwd=am02b0xIUXZ6TDR3d1dWL05TTDdaUT09)

The Green's function Monte Carlo (GFMC) method provides accurate solutions to the nuclear many-body problem and predicts properties of light nuclei starting from realistic two- and three-body interactions. Controlling the GFMC fermion-sign problem is crucial, as the signal-to-noise ratio decreases exponentially with Euclidean time. I will discuss recent work applying contour deformations to treat this sign problem and improve the GFMC signal-to-noise ratio. Proof-of-principle results include achieving an order of magnitude improvement in the variance of Euclidean density response functions of the deuteron, paving the way for computing electron- and neutrino-nucleus cross-sections of larger nuclei.

GFMCDeforms_08_06_2023.pdf