Fast estimator of Jacobians in the Monte Carlo integration on Lefschetz thimbles

Apr 4, 2016
8 pages
Published in:
  • Phys.Rev.D 93 (2016) 9, 094514
  • Published: May 26, 2016
e-Print:

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Abstract: (APS)
A solution to the sign problem is the so-called “Lefschetz thimble approach” where the domain of integration for field variables in the path integral is deformed from the real axis to a submanifold in the complex space. For properly chosen submanifolds (“thimbles”) the sign problem disappears or is drastically alleviated. The parametrization of the thimble by real coordinates requires the calculation of a Jacobian with a computational cost of order O(V3), where V is proportional to the spacetime volume. In this paper we propose two estimators for this Jacobian with a computational cost of order O(V). We discuss analytically the regimes where we expect the estimator to work and show numerical examples in two different models.
Note:
  • 10 pages, 3 figures
  • action: complex
  • potential: chemical
  • numerical methods: efficiency
  • estimator
  • parametrization
  • path integral
  • numerical calculations: Monte Carlo
  • deformation
  • Thirring model
  • toy model