7,989 research outputs found
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 () brane is physically meaningful
whereas de Sitter () and Minkowski () branes are dismissed.
Moreover, for 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
Renormalizability of Massive Gravity in Three Dimensions
We discuss renormalizability of a recently established, massive gravity
theory with particular higher derivative terms in three space-time dimensions.
It is shown that this massive gravity is certainly renormalizable as well as
unitary, so it gives us a physically interesting toy model of perturbative
quantum gravity in three dimensions.Comment: 13 pages, no figure
Ni-impurity effects on the superconducting gap of LaSrCuO studied from the magnetic field and temperature dependence of the electronic specific heat
The magnetic field and temperature dependence of the electronic specific heat
have been systematically investigated in (LSCNO) in order to study Ni-impurity
effects on the superconducting (SC) gap. In LSCNO with =0.15 and =0.015,
the value of () at =0 K, , is
enhanced under the magnetic field applied along the -axis. The
increment of , , follows the Volovik relation
=, characteristic of the SC gap with line nodes,
with prefactor similar to that of a pure sample. The vs.
curve under =0 shows a d-wave-like SC anomaly with an abrupt increase at
and -linear dependence at , although the
-value in the vs. curve increases with increasing
Ni concentrations. Interestingly, as the SC part of , , decreases in LSCNO, is
reduced in proportion to the decrease of . These findings can
be explained phenomenologically by a simple model in which Ni impurities bring
about strong pair breaking at the edges of the coherent nodal part of the Fermi
surface but in the vicinity of the nodes of the SC gap. The reduction of the SC
condensation energy in LSCNO, evaluated from at
{0.3em}\raisebox{0.4ex}{} {-0.75em}\raisebox{-.7ex}{} {0.3em}, is also understood by the same model.Comment: 7 pages, 6 figures, accepted in Phys. Rev.
The competitive effect of adenosine-5'-triphosphate against the stimulating and inhibiting actions of 2,4-dinitrophenol on the mitochondrial respiration
Effect of ATP and substrates on 2,4-dinitrophenol-induced adenosine triphcsphatase (E. C. 3.6. 1. 4.) activity and respiration of isolated rat liver mitochondria has been investigated. 1. The oxidation of sodium succinate inhibited the action of 2, 4-DNP
on the induction of adenosine triphosphatase activity in the mitochondria. 2. A moderately large amount of sodium succinate restored the suppressed mitochondrial respiration due to 2, 4-DNP.
3. Adenosine-5'-triphosphate (ATP) restored quantitatively the released and inhibited mitochondrial respiration due to 2,4-DNP, and its prior addition prevented also quantitatively the action of 2,4-DNP on the mitochondrial oxygen up-take. These ATP effects were oligomycin
sensitive, and they were considered to manifest their actions through the phosphorylation system.</p
Bottom-up fabrication of Si nanodot transistors using the nc-Si dots solution
A new approach to fabricate nanometer-scale silicon devices is recently attracting much attention, which combines the conventional top-down silicon processing techniques and the bottom-up assembly of silicon nanodots, whose structures are controlled on the atomic scale. This technique enables to investigate the electronic states and transport properties of strongly-coupled multiple nanodots which will be crucial particularly for quantum information device applications. Various unique properties have been studied in such systems. For example, electrostatic interactions have been investigated for double Si dots [1] and for the two-dimensional Si multidots [2]. Coherent wavefunction coupling and associated quasi-molecular states have also been observed for a tunnel-coupled double Si nanodots [3]. In addition, metal-insulator transition has been investigated for an artificial lattice of self-organized nano-paraticles [4]. In this paper we propose and examine a novel technique of fabricating nanoscale transistors with a Si nanodot cluster as a channel based on the self-assembly of the nanocrystalline Si dots from the solution on the patterned SOI substrates
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.
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