Singularity of the density of states in the two-dimensional Hubbard model from finite size scaling of Yang-Lee zeros

Abstract

A finite size scaling is applied to the Yang-Lee zeros of the grand canonical partition function for the 2-D Hubbard model in the complex chemical potential plane. The logarithmic scaling of the imaginary part of the zeros with the system size indicates a singular dependence of the carrier density on the chemical potential. Our analysis points to a second-order phase transition with critical exponent $\frac{1}{\delta }=\frac{1}{2}\pm \frac{1}{3}$ which leads to a divergence of the electronic susceptibility. We interprete these results as reflecting singular behaviour of the density of states in the quasiparticle spectrum.

Comments: 8 pages, Revtex