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 a bichromatic resonant pulse. The state vector evolution is studied for two different pulse designs. It is shown that the laser pulse can generate an effective exchange coupling between electron spins localized in different dots. Possible applications of this effect to quantum-information processing (entanglement generation, quantum-state engineering) are discussed.

Figure 1

Schematics of the states for a single electron confined in the double-dot structure. These one-electron states are used for construction of the two-electron states; see text for details.

Figure 2

Transition scheme connecting the states ∣1⟩ and ∣2⟩ through the use of the auxiliary states ∣5⟩, ∣6⟩, ∣7⟩, ∣8⟩, and ∣13⟩ in the case of the two-photon resonance ${\Delta }_1=-{\Delta }_2=\Delta$. Here ${\Delta }_1$ and ${\Delta }_2$ are the detunings of the pulse frequencies ${\omega }_1$ and ${\omega }_2$, respectively, from the exact resonance.

Figure 3

Transition scheme connecting the states ∣1⟩ and ∣2⟩ through the use of the auxiliary states ∣3⟩, ∣4⟩, ∣5⟩, ∣6⟩, ∣7⟩, and ∣8⟩ in the two-photon resonant case; see Fig. 2.