title: Coherent manipulation of coupled electron spins in semiconductor quantum dots.
abstract: 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, T2*, 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.
authors.affiliation: Department of Physics, Harvard University, Cambridge, MA 02138, USA.
authors.forename: J R
authors.initials: JR
authors.lastname: Petta
authors.forename: A C
authors.initials: AC
authors.lastname: Johnson
authors.forename: J M
authors.initials: JM
authors.lastname: Taylor
authors.forename: E A
authors.initials: EA
authors.lastname: Laird
authors.forename: A
authors.initials: A
authors.lastname: Yacoby
authors.forename: M D
authors.initials: MD
authors.lastname: Lukin
authors.forename: C M
authors.initials: CM
authors.lastname: Marcus
authors.forename: M P
authors.initials: MP
authors.lastname: Hanson
authors.forename: A C
authors.initials: AC
authors.lastname: Gossard