All optical quantum control of a spin-quantum state and ultrafast transduction into an electric current

Abstract

The ability to control and exploit quantum coherence and entanglement drives research across many fields ranging from ultra-cold quantum gases to spin systems in condensed matter. Transcending different physical systems, optical approaches have proven themselves to be particularly powerful, since they profit from the established toolbox of quantum optical techniques, are state-selective, contact-less and can be extremely fast. Here, we demonstrate how a precisely timed sequence of monochromatic ultrafast (~2-5 ps) optical pulses, with a well defined polarisation can be used to prepare arbitrary superpositions of exciton spin states in a semiconductor quantum dot, achieve ultrafast control of the spin-wavefunction without an applied magnetic field and make high fidelity read-out the quantum state in an arbitrary basis simply by detecting a strong (~2-10$ pA) electric current flowing in an external circuit. The results obtained show that the combined quantum state preparation, control and read-out can be performed with a near-unity (>97%) fidelity. Our methods are fully applicable to other quantum systems and have strong potential for scaling to more complex systems such as molecules and spin-chains.

References in corpus (9)

• Coherent Population Trapping of an Electron Spin in a Single Negatively Charged Quantum Dot
• Ultrafast optical control of entanglement between two quantum dot spins
• Observation of extremely slow hole spin relaxation in self-assembled quantum dots
• Fast optical preparation, control and read-out of single quantum dot spin
• Theory of fast optical spin rotation in a quantum dot based on geometric phases and trapped states
• Complete control of a matter qubit using a single picosecond laser pulse
• A Charge and Spin Readout Scheme For Single Self-Assembled Quantum Dots
• High fidelity optical preparation and coherent Larmor precession of a single hole in an InGaAs quantum dot molecule
• Optical Spin Initialization and Non-Destructive Measurement in a Quantum Dot Molecule

Cited by in corpus (11)

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• Circuit QED with Hole-Spin Qubits in Ge/Si Nanowire Quantum Dots
• Dissipative preparation of the exciton and biexciton in a self-assembled quantum dot on picosecond timescales
• Resonance fluorescence of GaAs quantum dots with near-unity photon indistinguishability
• The crux of using the cascaded emission of a 3-level quantum ladder system to generate indistinguishable photons
• Determinisitic Writing and Control of the Dark Exciton Spin using Short Single Optical Pulses
• Deterministic Coherent Writing of a Long-Lived Semiconductor Spin Qubit Using One Ultrafast Optical Pulse
• Non-linear two-photon resonance fluorescence on a single artificial atom
• Controlled tunneling induced dephasing of Rabi rotations for ultra-high fidelity hole spin initialization
• Ultrafast Coherent Manipulation of Trions in Site-Controlled Nanowire Quantum Dots
• Unraveling spin dynamics from charge fluctuations