Quantum transport through double-dot Aharonov-Bohm interferometry in Coulomb blockade regime

Transport through two quantum dots laterally embedded in Aharonov-Bohm interferometry with infinite intradot and arbitrary interdot Coulomb repulsion is analyzed in the weak coupling and Coulomb blockade regime. By employing the modified quantum rate equations and the slave-boson approach, we establish a general dc current formula at temperatures higher than the Kondo temperature for the case that the spin degenerate levels of two dots are close to each other. We examine two simple examples for identical dots - no doubly occupied states and no empty state. In the former, completely destructive coherent transport and phase locking appear at magnetic flux $\Phi=\Phi_{0}/2$ and $\Phi=0$ respectively; in the latter, partially coherent transport exhibits an oscillation with magnetic flux having a period of $\Phi_0$.Comment: 8 pages, 3 figure

Kondo correlation and spin-flip scattering in spin-dependent transport through a quantum dot coupled to ferromagnetic leads

We investigate the linear and nonlinear dc transport through an interacting quantum dot connected to two ferromagnetic electrodes around Kondo regime with spin-flip scattering in the dot. Using a slave-boson mean field approach for the Anderson Hamiltonian having finite on-site Coulomb repulsion, we find that a spin-flip scattering always depresses the Kondo correlation at arbitrary polarization strength in both parallel and antiparallel alignment of the lead magnetization and that it effectively reinforces the tunneling related conductance in the antiparallel configuration. For systems deep in the Kondo regime, the zero-bias single Kondo peak in the differential conductance is split into two peaks by the intradot spin-flip scattering; while for systems somewhat further from the Kondo center, the spin-flip process in the dot may turn the zero-bias anomaly into a three-peak structure.Comment: 4 pages, 2 figure

Hydrogen vehicles: Impacts of DOE technical targets on market acceptance and societal benefits

Hydrogen vehicles (H2V), including H2 internal combustion engine, fuel cell and fuel cell plug-in hybrid, could greatly reduce petroleum consumption and greenhouse gas (GHG) emissions in the transportation sector. The U.S. Department of Energy has adopted targets for vehicle component technologies to address key technical barriers to widespread commercialization of H2Vs. This study estimates the market acceptance of H2Vs and the resulting societal benefits and subsidy in 41 scenarios that reflect a wide range of progress in meeting these technical targets. Important results include: (1) H2Vs could reach 20–70% market shares by 2050, depending on progress in achieving the technical targets. With a basic hydrogen infrastructure (∼5% hydrogen availability), the H2V market share is estimated to be 2–8%. Fuel cell and hydrogen costs are the most important factors affecting the long-term market shares of H2Vs. (2) Meeting all technical targets on time could result in about an 80% cut in petroleum use and a 62% (or 72% with aggressive electricity de-carbonization) reduction in GHG in 2050. (3) The required hydrogen infrastructure subsidy is estimated to range from $22 to$47 billion and the vehicle subsidy from $4 to$17 billion. (4) Long-term H2V market shares, societal benefits and hydrogen subsidies appear to be highly robust against delay in one target, if all other targets are met on time. R&D diversification could provide insurance for greater societal benefits. (5) Both H2Vs and plug-in electric vehicles could exceed 50% market shares by 2050, if all targets are met on time. The overlapping technology, the fuel cell plug-in hybrid electric vehicle, appears attractive both in the short and long runs, but for different reasons

A study on the extraction and purification technology of tea sapogenin

In order to extract and purify tea sapogenin, first the extraction liquid is obtained using mechanically pressed tea-seeds as raw material, which will be decreased by organic solvent. When the conditions like the methanol volume fraction is 75v/v, solid-liquid is 1:4 and the ultrasonic frequency is 25.8 Hz, extract them for 30 min. After this, collect the extraction liquid and slowly add in Hz-841 macroporous resin column, then elute it with 0.3% NaOH. The third step is to elute with ethanol of different concentrations after the coloring pigment is got rid of, and then detect it with thin layer chromatography (TLC). It is discovered that there is only tea sapogenin in the 35 – 95v/v ethanol elution liquid. The last step is to collect the 95% ethanol elution liquid and vacuum condense it; and then tea-Tea sapogenin with a purity of 96% can be obtained

The effects of graded levels of calorie restriction : XI. Evaluation of the main hypotheses underpinning the life extension effects of CR using the hepatic transcriptome

We would like to acknowledge the BSU staff for their invaluable help with caring for the animals.Peer reviewedPublisher PD

Stability, Adiabaticity and Transfer efficiency in a nonlinear \Lambda-system

We investigate the relationship between stability, adiabaticity and transfer efficiency in a \Lambda-type atom-molecule coupling system via a nonlinear stimulated Raman adiabatic passage. We find that only when the pump and control lasers overlap in time domain, the coherent population trapping (CPT) state could become unstable. If the overlapping time of the two lasers is short so that unstable growth of the deviation from the CPT state is negligible, then good adiabaticity of the CPT state could be maintained even in the unstable region. In this case, a high atom-molecule transfer efficiency could be obtained by chirping applied laser pulses to elegantly compensate the frequency shift induced by intra-atomic collision. Our results could be useful for efficiently photoassociating ground-state molecules from a cold atomic gas with strong atom-atom collisional interaction

The effects of graded levels of calorie restriction : V. Impact of short term calorie and protein restriction on physical activity in the C57BL/6 mouse

Peer reviewedPublisher PD

Quantum contextuality for a relativistic spin-1/2 particle

The quantum predictions for a single nonrelativistic spin-1/2 particle can be reproduced by noncontextual hidden variables. Here we show that quantum contextuality for a relativistic electron moving in a Coulomb potential naturally emerges if relativistic effects are taken into account. The contextuality can be identified through the violation of noncontextuality inequalities. We also discuss quantum contextuality for the free Dirac electron as well as the relativistic Dirac oscillator.Comment: REVTeX4, 5 page