arXiv subjects
Publications and source records attributed to Zhe Sun.
We investigate effects of staggered magnetic field on thermal entanglement in the anisotropic XY model. The analytic results of entanglement for the two-site cases are obtained. For the general case of even sites, we show that when the anisotropic parameter is zero, the entanglement in the XY model with a staggered magnetic field is the same as that with a uniform magnetic field.
Citing the disappearance of a sharp peak in the electron self-energy, extracted from optics and angle-resolved photoemission spectroscopy (ARPES) experiments in deeply over-doped copper-oxide superconductors with Tc of 55-60K, Hwang, Timusk et al. argue that sharp modes, be they phononic or magnetic in origin, are not important for superconductivity in the cuprates. If true, this would have been an important progress. We show, however, their conclusions are unfounded because of the insensitivity of the optics experiment in studying strongly anisotropic material like the cuprates, and a misrepresentation of existing ARPES data. In an added note, we refute the claim by Valla, Timusk et. al. that the doping level of the data presented in the first part of this comment is lower than reported.