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

Charge qubit entanglement via conditional single-electron transfer in an array of quantum dots

We propose a novel scheme to generate entanglement among quantum-dot-based charge qubits via sequential electron transfer in an auxiliary quantum dot structure whose transport properties are conditioned by qubit states. The transfer protocol requires the utilization of resonant optical pulses combined with an appropriate voltage gate pattern. As an example illustrating the application of this scheme, we examine the nine-qubit Shor code state preparation together with the error syndrome measurement

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