Preparing, manipulating, and measuring quantum states on a chip

J. R. Petta, A. C. Johnson, J. M. Taylor, E. A. Laird, A. Yacoby, M. D. Lukin, C. M. Marcus, M. P. Hanson, A. C. Gossard

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


We use gate voltage control of the exchange interaction to prepare, manipulate, and measure two-electron spin states in a GaAs double quantum dot. By placing two electrons in a single dot at low temperatures we prepare the system in a spin singlet state. The spin singlet is spatially separated by transferring an electron to an adjacent dot. The spatially separated spin singlet state dephases in ∼ 10 ns due to the contact hyperfine interaction with the GaAs host nuclei. To combat the hyperfine dephasing, we develop quantum control techniques based on fast electrical control of the exchange interaction. We demonstrate coherent spin-state rotations in a singlet-triplet qubit and harness the coherent rotations to implement a singlet-triplet spin echo refocusing pulse sequence. The singlet-triplet spin echo extends the spin coherence time to 1.2 μ s.

Original languageEnglish (US)
Pages (from-to)251-256
Number of pages6
JournalPhysica E: Low-Dimensional Systems and Nanostructures
Issue number2
StatePublished - Dec 2006

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics


  • Coherent manipulation
  • Spin echo
  • Spin qubit


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