Spontaneous and persistent currents in mesoscopic Aharonov-Bohm loops: Static properties and coherent dynamic behavior in crossed electric and magnetic fields

摘要: Mesoscopic or macromolecular conducting rings with a fixed number of electrons are shown to support persistent currents due the Aharonov-Bohm flux, and “spontaneous” without flux when structural transformation in ring is blocked by strong coupling externally azimuthal-symmetric environment. In free-standing ring, symmetry breaking removes azimuthal periodicity, which further restored at increasing field, however. The dynamics loop crossed electric magnetic fields investigated within tight-binding approximation; we show that transitions between discrete quantum states occur static voltage pulses prescribed duration applied loop. particular, three-site one three an interesting system can serve as qubit (quantum bit information) qugate logical gate) because presence field perpendicular switches degenerate ground mimicking NOT Hadamard gates computers.