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 later recombining a singlet spin state provided a measurement of the spin dephasing time, T2*, of ∼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.

[1]  C. Slichter.  Principles of magnetic resonance , 1963 .

[2]  B. Sapoval,et al.  Low field electron-nuclear spin coupling in gallium arsenide under optical pumping conditions , 1977 .

[3]  K. Schulten,et al.  Semiclassical description of electron spin motion in radicals including the effect of electron hopping , 1978 .

[4]  Anthony J Leggett,et al.  Influence of Dissipation on Quantum Tunneling in Macroscopic Systems , 1981 .

[5]  Ritchie,et al.  Measurements of Coulomb blockade with a noninvasive voltage probe. , 1993, Physical review letters.

[6]  Lov K. Grover.  Quantum Mechanics Helps in Searching for a Needle in a Haystack , 1997, quant-ph/9706033.

[7]  D. DiVincenzo,et al.  Quantum computation with quantum dots , 1997, cond-mat/9701055.

[8]  D. DiVincenzo,et al.  Coupled quantum dots as quantum gates , 1998, cond-mat/9808026.

[9]  J. Levy.  Universal quantum computation with spin-1/2 pairs and Heisenberg exchange. , 2001, Physical review letters.

[10]  S. Tarucha,et al.  Allowed and forbidden transitions in artificial hydrogen and helium atoms , 2002, Nature.

[11]  A. Khaetskii,et al.  Electron spin decoherence in quantum dots due to interaction with nuclei. , 2002, Physical review letters.

[12]  Electron spin relaxation by nuclei in semiconductor quantum dots , 2002, cond-mat/0202271.

[13]  P. Joyez,et al.  Manipulating the Quantum State of an Electrical Circuit , 2002, Science.

[14]  D A Lidar,et al.  Creating decoherence-free subspaces using strong and fast pulses. , 2002, Physical review letters.

[15]  S. Tarucha,et al.  Current Rectification by Pauli Exclusion in a Weakly Coupled Double Quantum Dot System , 2002, Science.

[16]  S. Sarma,et al.  Theory of nuclear-induced spectral diffusion: Spin decoherence of phosphorus donors in Si and GaAs quantum dots , 2002, cond-mat/0211567.

[17]  P. Matagne,et al.  Experiments And Simulations On A Few‐Electron Quantum Dot Circuit With Integrated Charge Read‐Out , 2002, cond-mat/0212489.

[18]  L. Vandersypen,et al.  Single-shot read-out of an individual electron spin in a quantum dot , 2004, Nature.

[19]  Hyperfine interaction in a quantum dot: Non-Markovian electron spin dynamics , 2004, cond-mat/0405676.

[20]  A. Gossard,et al.  Manipulation of a single charge in a double quantum dot. , 2004, Physical review letters.

[21]  L. Vandersypen,et al.  NMR techniques for quantum control and computation , 2004, quant-ph/0404064.

[22]  Jacob M. Taylor,et al.  Triplet–singlet spin relaxation via nuclei in a double quantum dot , 2005, Nature.

[23]  P. Zoller,et al.  Solid-state circuit for spin entanglement generation and purification. , 2005, Physical review letters.

[24]  L. Vandersypen,et al.  Control and Detection of Singlet-Triplet Mixing in a Random Nuclear Field , 2005, Science.

[25]  M. Siaj,et al.  Creating, Varying, and Growing Single-Site Molecular Contacts , 2005, Science.

[26]  M D Barrett,et al.  Implementation of the Semiclassical Quantum Fourier Transform in a Scalable System , 2005, Science.

[27]  Optical pumping of the electronic and nuclear spin of single charge-tunable quantum dots. , 2004, Physical review letters.