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Environment-assisted quantum control of a solid state spin via 2-color coherent dark states



Jacob M. Taylor, Jack Hansom, Carsten Schulte, Claire Le Gall, Clemens Matthiesen, Edmund Clarke, Maxime Hugues, Mete Atature


Semiconductor quantum dots (QDs) offer an efficient and scalable interface between single spins and optical photons. However, the solid-state environment of the QD represents an inherent source of noise, generally considered detrimental to coherent control of the spin quantum bit. Here, we demonstrate the creation of electron spin superpositions through coherent population trapping (CPT) in the absence of an external magnetic field. The interaction of the electron spin with the nuclear spin bath lifts the degeneracy of spin- selective optical transitions, leading to a sub-linewidth spin splitting and directly providing the Λ-system required for CPT. Once a dark state is generated, we demonstrate multi-axis quantum control of the spin state, implemented through phase control of the laser fields and subsequent projection on a rotated basis. Spin control with sub-linewidth splitting of the optical transitions allows the possibility to generate many-photon cluster states11, with foreseeable implications for scalable measurement-based quantum computation.
Nature Physics


quantum dots, dark states, coherent population trapping


Taylor, J. , Hansom, J. , Schulte, C. , Le, C. , Matthiesen, C. , Clarke, E. , Hugues, M. and Atature, M. (2014), Environment-assisted quantum control of a solid state spin via 2-color coherent dark states, Nature Physics, [online], (Accessed March 3, 2024)
Created September 7, 2014, Updated November 10, 2018