Study of the ionic Peierls-Hubbard model using density matrix renormalization group methods

Density matrix renormalization group methods are used to investigate the quantum phase diagram of a one-dimensional half-filled ionic Hubbard model with bond-charge attraction, which can be mapped from the Su-Schrieffer-Heeger-type electron-phonon coupling at the antiadiabatic limit. A bond order wave (dimerized) phase which separates the band insulator from the Mott insulator always exists as long as electron-phonon coupling is present. This is qualitatively different from that at the adiabatic limit. Our results indicate that electron-electron interaction, ionic potential and quantum phonon fluctuations combine in the formation of the bond-order wave phase

Discussion on Event Horizon and Quantum Ergosphere of Evaporating Black Holes in a Tunnelling Framework

In this paper, with the Parikh-Wilczek tunnelling framework the positions of the event horizon of the Vaidya black hole and the Vaidya-Bonner black hole are calculated respectively. We find that the event horizon and the apparent horizon of these two black holes correspond respectively to the two turning points of the Hawking radiation tunnelling barrier. That is, the quantum ergosphere coincides with the tunnelling barrier. Our calculation also implies that the Hawking radiation comes from the apparent horizon.Comment: 8 page

Octupole degree of freedom for the critical-point candidate nucleus 152^{152}Sm in a reflection-asymmetric relativistic mean-field approach

The potential energy surfaces of even-even $^{146-156}$Sm are investigated in the constrained reflection-asymmetric relativistic mean-field approach with parameter set PK1. It is shown that the critical-point candidate nucleus $^{152}$Sm marks the shape/phase transition not only from U(5) to SU(3) symmetry, but also from the octupole-deformed ground state in $^{150}$Sm to the quadrupole-deformed ground state in $^{154}$Sm. By including the octupole degree of freedom, an energy gap near the Fermi surface for single-particle levels in $^{152}$Sm with $\beta_2 = 0.14 \sim 0.26$ is found, and the important role of the octupole deformation driving pair $\nu 2f_{7/2}$ and $\nu 1i_{13/2}$ is demonstrated.Comment: 11 pages, 3 figure