25,298 research outputs found
Electric Dipole Moments in the Generic Supersymmetric Standard Model
The generic supersymmetric standard model is a model built from a
supersymmetrized standard model field spectrum the gauge symmetries only. The
popular minimal supersymmetric standard model differs from the generic version
in having R-parity imposed by hand. We review an efficient formulation of the
model and some of the recently obtained interesting phenomenological features,
focusing on one-loop contributions to fermion electric dipole moments.Comment: 1+7 pages Revtex 3 figures incoporated; talk at NANP'0
In an Attempt to Introduce Long-range Interactions into Small-world Networks
Distinguishing the long-range bonds with the regular ones, the critical
temperature of the spin-lattice Guassian model built on two typical Small-world
Networks (SWNs) is studied. The results show much difference from the classical
case, and thus may induce some more accurate discussion on the critical
properties of the spin-lattice systems combined with the SWNs.Comment: 4 pages, 3 figures, 18 referenc
Scanning Tunneling Spectroscopy of Suspended Single-Wall Carbon Nanotubes
We have performed low-temperature STM measurements on single-wall carbon
nanotubes that are freely suspended over a trench. The nanotubes were grown by
CVD on a Pt substrate with predefined trenches etched into it. Atomic
resolution was obtained on the freestanding portions of the nanotubes.
Spatially resolved spectroscopy on the suspended portion of both metallic and
semiconducting nanotubes was also achieved, showing a Coulomb-staircase
behavior superimposed on the local density of states. The spacing of the
Coulomb blockade peaks changed with tip position reflecting a changing tip-tube
capacitance
Intrinsic Spin Hall Effect in the presence of Extrinsic Spin-Orbit Scattering
Intrinsic and extrinsic spin Hall effects are considered together on an equal
theoretical footing for the Rashba spin-orbit coupling in two-dimensional (2D)
electron and hole systems, using the diagrammatic method for calculating the
spin Hall conductivity. Our analytic theory for the 2D holes shows the expected
lowest-order additive result for the spin Hall conductivity. But, the 2D
electrons manifest a very surprising result, exhibiting a non-analyticity in
the Rashba coupling strength where the strictly extrinsic spin Hall
conductivity (for ) cannot be recovered from the
limit of the combined theory. The theoretical results are discussed in the
context of existing experimental results.Comment: 5 pages, 2 figure
Correlations and fluctuations of a confined electron gas
The grand potential and the response of a phase-coherent confined noninteracting electron gas depend
sensitively on chemical potential or external parameter . We compute
their autocorrelation as a function of , and temperature. The result
is related to the short-time dynamics of the corresponding classical system,
implying in general the absence of a universal regime. Chaotic, diffusive and
integrable motions are investigated, and illustrated numerically. The
autocorrelation of the persistent current of a disordered mesoscopic ring is
also computed.Comment: 12 pages, 1 figure, to appear in Phys. Rev.
Electronic excitation spectrum of metallic carbon nanotubes
We have studied the discrete electronic spectrum of closed metallic nanotube
quantum dots. At low temperatures, the stability diagrams show a very regular
four-fold pattern that allows for the determination of the electron addition
and excitation energies. The measured nanotube spectra are in excellent
agreement with theoretical predictions based on the nanotube band structure.
Our results permit the complete identification of the electron quantum states
in nanotube quantum dots.Comment: 4 pages, 3 figure
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