Space-time Uncertainty Principle from Breakdown of Topological Symmetry

Starting from topological quantum field theory, we derive space-time uncertainty relation with respect to the time interval and the spatial length proposed by Yoneya through breakdown of topological symmetry in the large N matrix model. This work suggests that the topological symmetry might be an underlying higher symmetry behind the space-time uncertainty principle of string theory.Comment: 6 pages, Late

Locally Localized Gravity Models in Higher Dimensions

We explore the possibility of generalizing the locally localized gravity model in five space-time dimensions to arbitrary higher dimensions. In a space-time with negative cosmological constant, there are essentially two kinds of higher-dimensional cousins which not only take an analytic form but also are free from the naked curvature singularity in a whole bulk space-time. One cousin is a trivial extension of five-dimensional model, while the other one is in essence in higher dimensions. One interesting observation is that in the latter model, only anti-de Sitter ($AdS_p$) brane is physically meaningful whereas de Sitter ($dS_p$) and Minkowski ($M_p$) branes are dismissed. Moreover, for $AdS_p$ brane in the latter model, we study the property of localization of various bulk fields on a single brane. In particular, it is shown that the presence of the brane cosmological constant enables bulk gauge field and massless fermions to confine to the brane only by a gravitational interaction. We find a novel relation between mass of brane gauge field and the brane cosmological constant.Comment: 20 pages, LaTex 2e, revised version (to appear in Phys. Rev. D

Cold dark matter and primordial superheavy particles

The hypothesis that cold dark matter consists of primordial superheavy particles, the decay of short lifetime component of which led to the observable mass of matter while long living component survived up to modern times manifesting its presence in high energetic cosmic rays particles is investigated.Comment: LaTeX, 5 pages, no figure

STM/STS Study on 4a X 4a Electronic Charge Order and Inhomogeneous Pairing Gap in Superconducting Bi2Sr2CaCu2O8+d

We performed STM/STS measurements on underdoped Bi2212 crystals with doping levels p ~ 0.11, ~ 0.13 and ~ 0.14 to examine the nature of the nondispersive 4a X 4a charge order in the superconducting state at T << Tc. The charge order appears conspicuously within the pairing gap, and low doping tends to favor the charge order. We point out the possibility that the 4a X 4a charge order will be dynamical in itself, and pinned down over regions with effective pinning centers. The pinned 4a X 4a charge order is closely related to the spatially inhomogeneous pairing gap structure, which has often been reported in STS measurements on high-Tc cuprates.Comment: 12 pages, 16 figures, to be published in Phys. Rev.