Real-time simulations of quantum spin chains: Density of states and reweighting approaches

  title={Real-time simulations of quantum spin chains: Density of states and reweighting approaches},
  author={Pavel Buividovich and Johann Ostmeyer},
  journal={Physical Review B},
We put the Density-of-States (DoS) approach to Monte-Carlo (MC) simulations under a stress test by applying it to a physical problem with the worst possible sign problem: the real time evolution of a non-integrable quantum spin chain. Benchmarks against numerical exact diagonalisation and stochastic reweighting are presented. Both MC methods, the DoS approach and reweighting, allow for simulations of spin chains as long as L = 40 , far beyond exact diagonalisability, though only for short… 

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