240 research outputs found

    Controlled Flow of Spin-Entangled Electrons via Adiabatic Quantum Pumping

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    We propose a method to dynamically generate and control the flow of spin-entangled electrons, each belonging to a spin-singlet, by means of adiabatic quantum pumping. The pumping cycle functions by periodic time variation of localized two-body interactions. We develop a generalized approach to adiabatic quantum pumping as traditional methods based on scattering matrix in one dimension cannot be applied here. We specifically compute the flow of spin-entangled electrons within a Hubbard-like model of quantum dots, and discuss possible implementations and identify parameters that can be used to control the singlet flow.Comment: 4 pages, 3 figure

    Adiabatic quantum pumping in an Aharonov-Bohm loop and in a Si-like nanowire: Role of interference in real space and in momentum space

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    We study the consequences of interference effects on the current generated by adiabatic quantum pumping in two distinct one-dimensional (1D) lattice model. The first model contains an Aharonov-Bohm (AB) loop within a tight-binding chain of lattice sites. The static AB phase is shown to strongly affect interference between the two arms of the loop, serving as an on-off switch and regulator for the pumped current. The second model simulates pumping in semiconductors with indirect band-gaps, by utilizing a tight-binding chain with next-nearest-neighbor coupling. The model exhibits signatures of interference between degenerate conduction band states with different Fermi wavevectors.Comment: 7 pages, 7 figure

    Transparent, Non-local, Species-selective Transport in an Optical Superlattice Containing Two Interacting Atom Species

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    In an optical superlattice of triple wells, containing two mutually interacting atom species in adjacent wells, we show that one species can be transported through the positions of the other species, yet avoiding significant overlap and direct interaction. The transfer protocol is optimized to be robust against missing atoms of either species in any lattice site, as well as against lattice fluctuations. The degree and the duration of the inter-species overlap during passage can be tuned, making possible controlled large-scale interaction-induced change of internal states.Comment: 7 pages and 5 figure
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