Equation of state and entropy of the doped 2d Hubbard Model

We study thermodynamic properties of the doped Hubbard model with nearest-neighbour hopping on the square lattice by Diagrammatic Monte Carlo and obtain results with controlled error bars in the thermodynamic limit. The behaviour of entropy reveals signatures of the insulating regime developing near half-filling at larger interactions: a maximum in the entropy as a function of density appears as the coupling strength is increased, along with an inflection point near half-filling evidencing a metal to insulator crossover. Cold atom simulations of the Hubbard model which prepare the sample adiabatically will find our data useful for thermometry.