Calculating Thermodynamics Properties of Quantum Systems by a non-Markovian Monte Carlo Procedure

We present a history-dependent Monte Carlo scheme for the efficient calculation of the free-energy of quantum systems, inspired by the Wang-Landau sampling and metadynamics method. When embedded in a path integral formulation, it is of general applicability to a large variety of Hamiltonians. In the two-dimensional quantum Ising model, chosen here for illustration, the accuracy of free energy, critical temperature, and specific heat is demonstrated as a function of simulation time, and successfully compared with the best available approaches, particularly the Wang-Landau method over two different Monte Carlo procedures.