Remarks on the reweighting method in the chemical potential direction

Abstract

We comment on the reweighting method in the chemical potential $({\mu }_{\mathrm{q}})$ direction. We study the fluctuation of the reweighting factor during Monte-Carlo steps. We find that it is the absolute value of the reweighting factor that mainly contributes to the shift of the phase transition line $({\beta }_c)$ by the presence of ${\mu }_{\mathrm{q}}$. The phase fluctuation is a cause of the sign problem, but the effect on ${\beta }_c$ seems to be small. We also discuss ${\beta }_c$ for Iso-vector chemical potential and ${\beta }_c$ determined from simulations with imaginary chemical potential.

Comments: 5pages, 2 figures, Contribution to SEWM 2002 (Heidelberg, 2-5 October 2002)