Sophia E. Economou

Stimulated and spontaneous optical generation of electron spin coherence in charged GaAs quantum dots

We report on the coherent optical excitation of electron spin polarization in the ground state of charged GaAs quantum dots via an intermediate charged exciton (trion) state. Coherent optical fields are used for the creation and detection of the Raman spin coherence between the spin ground states of the charged quantum dot. The measured spin decoherence time, which is likely limited by the nature of the spin ensemble, approaches 10 ns at zero field. We also show that the Raman spin coherence in the quantum beats is caused not only by the usual stimulated Raman interaction but also by simultaneous spontaneous radiative decay of either excited trion state to a coherent combination of the two spin states.

Quantum control of a spin qubit coupled to a photonic crystal cavity

Using a long-lived quantum-dot spin qubit coupled to a GaAs-based photonic crystal cavity, researchers demonstrate complete quantum control of an electron spin qubit. By cleverly controlling the charge state of the InAs quantum dot using laser pulses, optical initialization, control and readout of an electron spin are achieved.

Theory of fast optical spin rotation in a quantum dot based on geometric phases and trapped states.

A method is proposed for the optical rotation of the spin of an electron in a quantum dot using excited trion states to implement operations significantly faster than those of most existing proposals. Key ingredients are the geometric phase induced by 2pi hyperbolic secant pulses, use of coherently trapped states and use of naturally dark states. Our proposal covers a variety of quantum dots by addressing different parameter regimes. Numerical simulations with typical parameters for InAs self-assembled quantum dots, including their dissipative dynamics, give fidelities of the operations in excess of 99%.

Spin coherence and echo modulation of the silicon vacancy in4H−SiCat room temperature

The silicon vacancy in silicon carbide is a strong emergent candidate for applications in quantum information processing and sensing. We perform room temperature optically-detected magnetic resonance and spin echo measurements on an ensemble of vacancies and find the properties depend strongly on magnetic field. The spin echo decay time varies from less than 10

Unified theory of consequences of spontaneous emission in a A system

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Scalable qubit architecture based on holes in quantum dot molecules

s at low fields to 80

Directing nuclear spin flips in InAs quantum dots using detuned optical pulse trains.

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Spin–cavity interactions between a quantum dot molecule and a photonic crystal cavity

s at 68 mT, and a strong field-dependent spin echo modulation is also observed. The modulation is attributed to the interaction with nuclear spins and is well-described by a theoretical model.

Silicon vacancy center in4H-SiC: Electronic structure and spin-photon interfaces

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Electron-Nuclear Dynamics in a Quantum Dot under Nonunitary Electron Control

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