3,927 research outputs found

    Photon-Assisted Quasiparticle Transport and Andreev Transport through an Interacting Quantum Dot

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    Resonant tunneling through a quantum dot coupled to superconducting reservoirs in the presence of time-dependent external voltage has been studied. A general formula of the current is derived based on the nonequilibrium Green's function technique. Using this formula photon-assisted quasiparticle transport has been investigated for the quantum dot connected to superconductors. In addition, resonant Andreev transport through a strongly correlated quantum dot connected to a normal metallic lead and a superconducting lead is studied.Comment: 9 pages(1 column) with 3 figure

    Exploring Dynamics between Instructional Designers and Higher Education Faculty: An Ethnographic Case Study

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    This study concentrated on individual and team traits of an instructional design team in the presence of a robust relationship between the team members and faculty at a southeast state university in U.S.A. Three exploratory themes emerged from the interpersonal dynamics observed in this qualitative inquiry: (1) expertise, (2) work motivation, and (3) team culture. Preliminary results first suggested that professionalism with a mix of task mental models, assertiveness, and proactivity be implanted in the instructional designers. Then, instructional designers’ growth and survival needs allow for active learning and continuous reflection on curriculum development and instruction delivery in the e-Learning business. Next, loose-tight leadership, collective cognition, and collegiality are rooted in the team culture as the instructional design team becomes established. Implications and recommendations were discussed in the research study

    Suppression of 2\pi\ phase-slip due to hidden zero modes in one dimensional topological superconductors

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    We study phase slips in one-dimensional topological superconducting wires. These wires have been proposed as building blocks for topologically protected qubits in which the quantum information is distributed over the length of the device and thus is immune to local sources of decoherence. However, phase-slips are non-local events that can result in decoherence. Phase slips in topological superconductors are peculiar for the reason that they occur in multiples of 4\pi\ (instead of 2\pi\ in conventional superconductors). We re-establish this fact via a beautiful analogy to the particle physics concept of dynamic symmetry breaking by explicitly finding a "hidden" zero mode in the fermion spectrum computed in the background of a 2\pi\ phase-slip. Armed with the understanding of phase-slips in topological superconductors, we propose a simple experimental setup with which the predictions can be tested by monitoring tunneling rate of a superconducting flux quantum through a topological superconducting wire.Comment: 18 pages,14 figures, Updated referenc

    Attitude Determination and Control System With Variable-Speed Single-Gimbal Control Moment Gyroscopes for Nanosatellites

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    This paper presents a novel Attitude Determination and Control System (ADCS) utilizing Variable-Speed Control Moment Gyroscopes (VSCMG) tailored explicitly for nanosatellites. The VSCMG was realized by spherical motor technology, in which a patented magnetic field design controls the inner rotor and gimbal. Because of the characteristics of the control moment gyroscope, the proposed ADCS offers improved attitude maneuverability and reduced power consumption, addressing the limitations of traditional ADCS solutions for nanosatellites. Furthermore, the adoption of spherical motor technology shrinks the VSCMG into a smaller form factor, which allows the VSCMG to be fitted into a nanosatellite. This research paper introduces the specifications of the integrated ADCS family based on VSCMG, as well as the components used in the system
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