1210.7201 (J. Vucicevic et al.)

Finite temperature crossovers and the quantum Widom line near the Mott
transition    [PDF]

J. Vucicevic, H. Terletska, D. Tanaskovic, V. Dobrosavljevic

We explore the recently established quantum critical region above the critical end-point in the half-filled Hubbard model. The resistivity displays characteristic quantum critical scaling near the instability line which we interpret as the quantum Widom line, in a close analogy with the Widom line in classical phase transitions. This line is determined by the minimum curvature of the free energy functional and represents a continuation of the line of the first order phase transition. The quantum Widom line, however, does not require the existence of the first order phase transition. It is rather a consequence of the zero temperature quantum phase transition, which in our case is masked by the phase coexistence region. Along the quantum Widom line the density of states is reduced, but the insulating gap is not yet fully open. We contrast this line with the Fermi liquid coherence line which is the boundary of the existence of long-lived quasiparticles.

View original: http://arxiv.org/abs/1210.7201