Papers by Keyword: Quantum Interference

Abstract: We propose a four-terminal nano device made of quantum wires with Rashba spin-orbit (SO) coupling. In each terminal there are several independent channels formed with quantum wires. The coherent transmission of electrons in such a nano system is a combined effect of quantum interference and spin precession. When defining two opposite terminals as source and drain leads, the charge and spin currents in channels of other two terminals exhibit spatial distributions which reflect the competition between spin precession and quantum interference during the tunneling of electrons. Since the four-terminal nano device is geometrically simple for the moving paths of charge and spin, our investigation may shed some light on the basic physical picture on this issue.

Abstract: We studied transport properties through a noninteracting quantum dots array with a side quantum dot employing the equation of motion method and Green function technique. The linear conductance has been calculated numerically. It is shown that an antiresonance always pinned at the energy level of side quantum dot. The conductance develops Fano line shape when the side quantum dot level is not aligned with that of the quantum dots in the array due to quantum interference through different channels.

Abstract: The frequency-sensitive optical response due to two-photon resonance of electromagnetically induced transparency (EIT) in a tunable band structure of an EIT-based layered medium is considered. The unit cells of this periodic layered structure are composed of dielectric (e.g., GaAs) and EIT atomic vapor. The frequency-sensitive behavior of controllable reflectance and transmittance depending on the external control field can be applicable to new device design (e.g., it can serve as the fundamental working mechanism for photonic switches and photonic logic gates). Some two-input logic gates (e.g., OR and NAND gates) are designed based on the present effect of sensitive switching control that results from the two-photon resonance.