Universality class of quantum criticality in the two-dimensional Hubbard model at intermediate temperatures ( t2/U≪T≪t )
Kaden R. A. Hazzard, Ana María Rey, Richard T. Scalettar
By using numerically exact determinantal Monte Carlo we show that the dilute Fermi gas quantum critical theory quantitatively describes the behavior of the density and compressibility along the Mott/metal crossover in the two-dimensional Hubbard model for temperatures somewhat less than (roughly half) the tunneling but greater than (roughly twice) the superexchange energy. In contrast, we find that other observables such as the kinetic energy, doubly occupied sites, and magnetization in a finite Zeeman field are poorly described by the same dilute Fermi gas universality class. In addition to these findings' fundamental interest, they are relevant to cold atom systems, where the intermediate temperature regime is currently in experimental reach.
arXiv:1106.2330•Physical Review B•Jan 7, 2013•4 citations