1,829 research outputs found
Brownian scattering of a spinon in a Luttinger liquid
We consider strongly interacting one-dimensional electron liquids where
elementary excitations carry either spin or charge. At small temperatures a
spinon created at the bottom of its band scatters off low-energy spin- and
charge-excitations and follows the diffusive motion of a Brownian particle in
momentum space. We calculate the mobility characterizing these processes, and
show that the resulting diffusion coefficient of the spinon is parametrically
enhanced at low temperatures compared to that of a mobile impurity in a
spinless Luttinger liquid. We briefly discuss that this hints at the relevance
of spin in the process of equilibration of strongly interacting one-dimensional
electrons, and comment on implications for transport in clean single channel
quantum wires
Interaction-induced backscattering in short quantum wires
We study interaction-induced backscattering in clean quantum wires with
adiabatic contacts exposed to a voltage bias. Particle backscattering relaxes
such systems to a fully equilibrated steady state only on length scales
exponentially large in the ratio of bandwidth of excitations and temperature.
Here we focus on shorter wires in which full equilibration is not accomplished.
Signatures of relaxation then are due to backscattering of hole excitations
close to the band bottom which perform a diffusive motion in momentum space
while scattering from excitations at the Fermi level. This is reminiscent to
the first passage problem of a Brownian particle and, regardless of the
interaction strength, can be described by an inhomogeneous Fokker-Planck
equation. From general solutions of the latter we calculate the hole
backscattering rate for different wire lengths and discuss the resulting length
dependence of interaction-induced correction to the conductance of a clean
single channel quantum wire.Comment: 10 pages, 4 figure
Endstates in multichannel spinless p-wave superconducting wires
Multimode spinless p-wave superconducting wires with a width W much smaller
than the superconducting coherence length \xi are known to have multiple
low-energy subgap states localized near the wire's ends. Here we compare the
typical energies of such endstates for various terminations of the wire: A
superconducting wire coupled to a normal-metal stub, a weakly disordered
superconductor wire and a wire with smooth confinement. Depending on the
termination, we find that the energies of the subgap states can be higher or
lower than for the case of a rectangular wire with hard-wall boundaries.Comment: 10 pages, 7 figure
Scattering of rare-gas atoms at a metal surface: evidence of anticorrugation of the helium-atom potential-energy surface and the surface electron density
Recent measurements of the scattering of He and Ne atoms at Rh(110) suggest
that these two rare-gas atoms measure a qualitatively different surface
corrugation: While Ne atom scattering seemingly reflects the electron-density
undulation of the substrate surface, the scattering potential of He atoms
appears to be anticorrugated. An understanding of this perplexing result is
lacking. In this paper we present density functional theory calculations of the
interaction potentials of He and Ne with Rh(110). We find that, and explain
why, the nature of the interaction of the two probe particles is qualitatively
different, which implies that the topographies of their scattering potentials
are indeed anticorrugated.Comment: RevTeX, 4 pages, 10 figure
Transport in the XX chain at zero temperature: Emergence of flat magnetization profiles
We study the connection between magnetization transport and magnetization
profiles in zero-temperature XX chains. The time evolution of the transverse
magnetization, m(x,t), is calculated using an inhomogeneous initial state that
is the ground state at fixed magnetization but with m reversed from -m_0 for
x0. In the long-time limit, the magnetization evolves into a
scaling form m(x,t)=P(x/t) and the profile develops a flat part (m=P=0) in the
|x/t|1/2 while it
expands with the maximum velocity, c_0=1, for m_0->0. The states emerging in
the scaling limit are compared to those of a homogeneous system where the same
magnetization current is driven by a bulk field, and we find that the
expectation values of various quantities (energy, occupation number in the
fermionic representation) agree in the two systems.Comment: RevTex, 8 pages, 3 ps figure
Characterization of seedling and adult-plant resistance to stem rust race Ug99 in Iranian bread wheat landraces
The full-length infectious cDNA clone was constructed and sequenced from the strain DM of echovirus 9, which was recently isolated from a 6-week-old child at the clinical onset of type 1 diabetes. Parallel with the isolate DM, the full-length infectious cDNA clone of the prototype strain echovirus 9 Barty (Barty-INF), was constructed and sequenced. Genetic relationships of the sequenced echo 9 viruses to the other members of the human enterovirus type B species were studied by phylogenetic analyses. Comparison of capsid protein sequences showed that the isolate DM was closely related to both prototype strains: Hill and Barty-INF. The only exception was the inner capsid protein VP4 where serotype specificity was not evident and the isolate DM clustered with the strain Hill and the strain Barty-INF with echovirus 30 Bastianni. Likewise, the nonstructural protein coding region, P2P3, of isolate DM was more similar to strain Hill than to strain Barty-INF. However, like echovirus 9 Barty, the isolate DM contained the RGD-motif in the carboxy terminus of capsid protein VP1. By blocking experiments using an RGD-containing peptide and a polyclonal rabbit antiserum to the alpha(v)beta(3)-integrin, it was shown that this molecule works as a cellular receptor for isolate DM. By using primary human islets, it was shown that the isolate DM is capable of infecting insulin-producing beta-cells like the corresponding prototype strains did. However, only isolate DM was clearly cytolytic for beta-cells. The infectious clones that were made allow further investigations of the molecular features responsible for the diabetogenicity of the isolate DM
Heat conduction in the diatomic Toda lattice revisited
The problem of the diverging thermal conductivity in one-dimensional (1-D)
lattices is considered. By numerical simulations, it is confirmed that the
thermal conductivity of the diatomic Toda lattice diverges, which is opposite
to what one has believed before. Also the diverging exponent is found to be
almost the same as the FPU chain. It is reconfirmed that the diverging thermal
conductivity is universal in 1-D systems where the total momentum preserves.Comment: 3 pages, 3 figures. To appear in Phys. Rev.
Controlling the energy flow in nonlinear lattices: a model for a thermal rectifier
We address the problem of heat conduction in 1-D nonlinear chains; we show
that, acting on the parameter which controls the strength of the on site
potential inside a segment of the chain, we induce a transition from conducting
to insulating behavior in the whole system. Quite remarkably, the same
transition can be observed by increasing the temperatures of the thermal baths
at both ends of the chain by the same amount. The control of heat conduction by
nonlinearity opens the possibility to propose new devices such as a thermal
rectifier.Comment: 4 pages with figures included. Phys. Rev. Lett., to be published
(Ref. [10] corrected
Simulational Study on Dimensionality-Dependence of Heat Conduction
Heat conduction phenomena are studied theoretically using computer
simulation. The systems are crystal with nonlinear interaction, and fluid of
hard-core particles. Quasi-one-dimensional system of the size of is simulated. Heat baths are put in both end:
one has higher temperature than the other. In the crystal case, the interaction
potential has fourth-order non-linear term in addition to the harmonic
term, and Nose-Hoover method is used for the heat baths. In the fluid case,
stochastic boundary condition is charged, which works as the heat baths.
Fourier-type heat conduction is reproduced both in crystal and fluid models in
three-dimensional system, but it is not observed in lower dimensional system.
Autocorrelation function of heat flux is also observed and long-time tails of
the form of , where denotes the dimensionality of the
system, are confirmed.Comment: 4 pages including 3 figure
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