Absence of Hysteresis at the Mott-Hubbard Metal-Insulator Transition in Infinite Dimensions

The nature of the Mott-Hubbard metal-insulator transition in the infinite-dimensional Hubbard model is investigated by quantum Monte Carlo simulations down to temperature T0ex0ex=0ex0exW/140 ( W0ex0ex=0ex0exbandwidth). Calculating with significantly higher precision than in previous work, we show that the hysteresis below TIPT0.022W, reported in earlier studies, disappears. Hence the transition is found to be continuous rather than discontinuous down to at least T0ex0ex=0ex0ex0.325TIPT. We also study the changes in the density of states across the transition, which illustrate that the Fermi liquid breaks down before the gap opens.