Coherent control with optical pulses for deterministic spin-photon entanglement

Abstract

We present a procedure for the optical coherent control of quantum bits within a quantum dot spin-exciton system, as a preliminary step to implementing a proposal by Yao, Liu, and Sham [Phys. Rev. Lett. 95, 030504 (2005)] for deterministic spin-photon entanglement. The experiment proposed here utilizes a series of picosecond optical pulses from a single laser to coherently control a single self-assembled quantum dot in a magnetic field, creating the precursor state in 25 ps with a predicted fidelity of 0.991. If allowed to decay in an appropriate cavity, the ideal precursor superposition state would create maximum spin-photon entanglement. Numerical simulations using values typical of InAs quantum dots give a predicted entropy of entanglement of 0.929, largely limited by radiative decay and electron spin flips.

Coherent population trapping in negatively charged self-assembled quantum dots using a train of femtosecond pulses

“…are the time-dependent Rabi frequencies with the associated transition dipole moments μ x and μ y where μ x = μ T +X− = μ T −X+ and μ * x = μ x whereas μ y = μ T +X+ = μ T −X− , μ * y = − μ y , and μ y = iμ x [29]. The area of the individual pulse in the pulse train is defined as = ∞ −∞ α(t)dt, with…”

Quantum Entanglement of Quantum Dot Spin Using Flying Qubits

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Coherent Control to Prepare an InAs Quantum Dot for Spin-Photon Entanglement

“…Here the cavity dynamics are replaced with decay by interaction with the vacuum. In the procedure, based on that proposed by Truex et al [10], the coherent optical excitation of the preentangled state involves first the preparation of a coherent superposition state, followed by a coherent transferal of one component of the superposition to the ground state. If the remaining component of the preentangled state could radiate into only one mode, the emitted photon would be entangled with the remaining spin.…”