Coherent Manipulation of Coupled Electron Spins in Semiconductor Quantum Dots

We demonstrated coherent control of a quantum two-level system based on two-electron spin states in a double quantum dot, allowing state preparation, coherent manipulation, and projective readout. These techniques are based on rapid electrical control of the exchange interaction. Separating and late...

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Bibliographic Details
Published in:Science (American Association for the Advancement of Science) 2005-09, Vol.309 (5744), p.2180-2184
Main Authors: Petta, J. R, Johnson, A. C, Taylor, J. M, Laird, E. A, Yacoby, A, Lukin, M. D, Marcus, C. M, Hanson, M. P, Gossard, A. C
Format: Article
Language:English
Subjects:
Classical and quantum physics: mechanics and fields
Condensed matter: electronic structure, electrical, magnetic, and optical properties
Electric potential
Electron spin
Electron states and collective excitations in thin films, multilayers, quantum wells, mesoscopic and nanoscale systems
Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures
Electrons
Exact sciences and technology
Ground state
Magnetic fields
Physics
Quantum computation
Quantum dots
Quantum information
Semiconductors
Sensors
Singlet state
Statistics
Testing
Tunnels
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Summary:We demonstrated coherent control of a quantum two-level system based on two-electron spin states in a double quantum dot, allowing state preparation, coherent manipulation, and projective readout. These techniques are based on rapid electrical control of the exchange interaction. Separating and later recombining a singlet spin state provided a measurement of the spin dephasing time, Tâ‚‚*, of [approximately]10 nanoseconds, limited by hyperfine interactions with the gallium arsenide host nuclei. Rabi oscillations of two-electron spin states were demonstrated, and spin-echo pulse sequences were used to suppress hyperfine-induced dephasing. Using these quantum control techniques, a coherence time for two-electron spin states exceeding 1 microsecond was observed.
ISSN:0036-8075
1095-9203
DOI:10.1126/science.1116955