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-d imensional Hubbard model is investigated by quantum Monte Carlo simulations down to temperature T = W/140 (W = bandwidth). Calculating with significan tly higher precision than in previous work, we show that the hysteresis bel ow T-IPT similar or equal to 0.022W, reported in earlier studies, disappear s. Hence the transition is found to be continuous rather than discontinuous down to at least T = 0.325T(IPT). We also study the changes in the density of states across the transition, which illustrate that the Fermi liquid br eaks down before the gap opens. [S0031-9007(99)09321-7].