55,011 research outputs found
Tunneling between helical Majorana modes and helical Luttinger liquids
We propose and study the charge transport through single and double quantum
point contacts setup between helical Majorana modes and an interacting helical
Luttinger liquid. We show that the differential conductance decreases for
stronger repulsive interactions and that the point contacts become insulating
above a critical interaction strength. For a single point contact, the
differential conductance as a function of bias voltage shows a series of peaks
due to Andreev reflection of electrons in the Majorana modes. In the case of
two point contacts, interference phenomena make the structure of the individual
resonance peaks less universal and show modulations with different separation
distance between the contacts. For small separation distance the overall
features remain similar to the case of a single point contact.Comment: v.2: 14 pages, 11 figures; adding one figure, an appendix, and some
minor change
APPLICATION OF PRICE ELASTICITIES TO FARM POLICY ANALYSIS: COMMENT
Demand and Price Analysis,
Kondo effect in coupled quantum dots with RKKY interaction: Finite temperature and magnetic field effects
We study transport through two quantum dots coupled by an RKKY interaction as
a function of temperature and magnetic field. By applying the Numerical
Renormalization Group (NRG) method we obtain the transmission and the linear
conductance. At zero temperature and magnetic field, we observe a quantum phase
transition between the Kondo screened state and a local spin singlet as the
RKKY interaction is tuned. Above the critical RKKY coupling the Kondo peak is
split. However, we find that both finite temperature and magnetic field restore
the Kondo resonance. Our results agree well with recent transport experiments
on gold grain quantum dots in the presence of magnetic impurities.Comment: 4 pages, 5 figure
Quasirandom permutations are characterized by 4-point densities
For permutations π and τ of lengths |π|≤|τ| , let t(π,τ) be the probability that the restriction of τ to a random |π| -point set is (order) isomorphic to π . We show that every sequence {τj} of permutations such that |τj|→∞ and t(π,τj)→1/4! for every 4-point permutation π is quasirandom (that is, t(π,τj)→1/|π|! for every π ). This answers a question posed by Graham
Quasinormal Modes of Kerr Black Holes in Four and Higher Dimensions
We analytically calculate to leading order the asymptotic form of quasinormal
frequencies of Kerr black holes in four, five and seven dimensions. All the
relevant quantities can be explicitly expressed in terms of elliptical
integrals. In four dimensions, we confirm the results obtained by Keshest and
Hod by comparing the analytic results to the numerical ones.Comment: 14 pages, 7 figure
ESTIMATING THE EFFECT OF HOUSEHOLD AGE-SEX COMPOSITION ON FOOD EXPENDITURES
Food Consumption/Nutrition/Food Safety,
A global approach for using kinematic redundancy to minimize base reactions of manipulators
An important consideration in the use of manipulators in microgravity environments is the minimization of the base reactions, i.e. the magnitude of the force and the moment exerted by the manipulator on its base as it performs its tasks. One approach which was proposed and implemented is to use the redundant degree of freedom in a kinematically redundant manipulator to plan manipulator trajectories to minimize base reactions. A global approach was developed for minimizing the magnitude of the base reactions for kinematically redundant manipulators which integrates the Partitioned Jacobian method of redundancy resolution, a 4-3-4 joint-trajectory representation and the minimization of a cost function which is the time-integral of the magnitude of the base reactions. The global approach was also compared with a local approach developed earlier for the case of point-to-point motion of a three degree-of-freedom planar manipulator with one redundant degree-of-freedom. The results show that the global approach is more effective in reducing and smoothing the base force while the local approach is superior in reducing the base moment
Two-stage Kondo effect in side-coupled quantum dots: Renormalized perturbative scaling theory and Numerical Renormalization Group analysis
We study numerically and analytically the dynamical (AC) conductance through
a two-dot system, where only one of the dots is coupled to the leads but it is
also side-coupled to the other dot through an antiferromagnetic exchange (RKKY)
interaction. In this case the RKKY interaction gives rise to a ``two-stage
Kondo effect'' where the two spins are screened by two consecutive Kondo
effects. We formulate a renormalized scaling theory that captures remarkably
well the cross-over from the strongly conductive correlated regime to the low
temperature low conductance state. Our analytical formulas agree well with our
numerical renormalization group results. The frequency dependent current noise
spectrum is also discussed.Comment: 6 pages, 7 figure
HOUSEHOLD FLUID MILK EXPENDITURE PATTERNS IN THE SOUTH AND UNITED STATES
Food Consumption/Nutrition/Food Safety,
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