arXiv subjects

Pascal Törek

Publications and source records attributed to Pascal Törek.

20 records · Page 2Linked to original sources

arXiv2015

Density of states method for the Z(3) spin model

We apply the density of states approach to the Z(3) spin model with a chemical potential mu. For determining the density of states we use restricted Monte Carlo simulations on small intervals of the variable for the density. In each interval we probe the response of the system to the variation of a free parameter in the Boltzmann factor. This response is a known function which we fit to the Monte Carlo data and the parameters of the density are obtained from that fit (functional fit approch; FFA). We evaluate observables related to the particle number and the particle number susceptibility, as well as the free energy. We find that for a surprisingly large range of mu the results from the FFA agree very well with the results from a reference simulation in the dual formulation of the Z(3) spin model which is free of the complex action problem.

hep-lat↗

arXiv2014

The Z3 model with the density of states method

In this contribution we apply a new variant of the density of states method to the Z3 spin model at finite density. We use restricted expectation values evaluated with Monte Carlo simulations and study their dependence on a control parameter lambda. We show that a sequence of one-parameter fits to the Monte-Carlo data as a function of lambda is sufficient to completely determine the density of states. We expect that this method has smaller statistical errors than other approaches since all generated Monte Carlo data are used in the determination of the density. We compare results for magnetization and susceptibility to a reference simulation in the dual representation of the Z3 spin model and find good agreement for a wide range of parameters.

hep-lat↗