Rabi oscillations in the four-level double-dot structure under the influence of the resonant pulse

We study theoretically the quantum dynamics of an electron in the symmetric four-level double-dot structure under the influence of the monochromatic resonant pulse. The probability amplitudes of the eigenstates relevant for the quantum dynamics are found from the solution of the non-stationary Schr\"odinger equation. The first-order correction term to the solution obtained through the rotating wave approximation is calculated. The three-level double-dot dynamics and the two-level single-dot dynamics, as well as the off-resonant excitation process, are derived from the general formulae for corresponding choices of the pulse and structure parameters. The results obtained may be applied to the solid-state qubit design.Comment: Accepted for publication in Phys. Rev.

Entanglement and quantum state engineering in the optically driven two-electron double-dot structure

We study theoretically the quantum dynamics of two interacting electrons in the symmetric double-dot structure under the influence of the bichromatic resonant pulse. The state vector evolution is studied for two different pulse designs. It is shown that the laser pulse can generate the effective exchange coupling between the electron spins localized in different dots. Possible applications of this effect to the quantum information processing (entanglement generation, quantum state engineering) are discussed.Comment: 28 pages, 3 figure

Selective electron transfer between the quantum dots under the resonant pulse

The coherent quantum dynamics of an electron in the quantum-dot ring structure under the resonant electromagnetic pulse is studied theoretically. A possibility of the selective electron transfer between any two dots is demonstrated. The transfer probability as a function of the pulse and dot parameters is calculated. It is shown that this probability can be close to unity. The factors lowering the transfer probability in real systems are discussed. The results obtained may be used in the engineering of novel nanoelectronic devices for quantum bits processing.Comment: Presented at the International Symposium "Quantum Informatics - 2004", Moscow, October 5-8, 2004; to appear in Fiz. Tekh. Poluprovodn. (St. Petersburg

Resonant optical electron transfer in one-dimensional multiwell structures

We consider coherent single-electron dynamics in the one-dimensional nanostructure under resonant electromagnetic pulse. The structure is composed of two deep quantum wells positioned at the edges of structure and separated by a sequence of shallow internal wells. We show that complete electron transfer between the states localized in the edge wells through one of excited delocalized states can take place at discrete set of times provided that the pulse frequency matches one of resonant transition frequencies. The transfer time varies from several tens to several hundreds of picoseconds and depends on the structure and pulse parameters. The results obtained in this paper can be applied to the developments of the quantum networks used in quantum communications and/or quantum information processing.Comment: 25 pages,16 figure

Quantum register based on structured diamond waveguide with NV centers

We propose a scheme of quantum information processing with NV-centers embedded inside diamond nanostructure. Single NV-center placed in the cavity plays role of an electron spin qubit which evolution is controlled by microwave pulses. Besides, it couples to the cavity field via optical photon exchange. In their turn, neighbor cavities are coupled to each other through the photon hopping to form a bus waveguide mode. This waveguide mode overlaps with all NV-centers. Entanglement between distant centers is organized by appropriate tuning of their optical frequency relative to the waveguide frequency via electrostatic control without lasers. We describe the controlled-Z operation that is by one order of magnitude faster than in off-resonant laser-assisted schemes proposed earlier. Spectral characteristics of the one-dimensional chain of microdisks are calculated by means of numerical modeling, using the approach analogous to the tight-binding approximation in the solid-state physics. The data obtained allow to optimize the geometry of the microdisk array for the effective implementation of quantum operations.Comment: to be published in Proc. of SPI