TY - JOUR
T1 - Quantum information processing using localized ensembles of nuclear spins
Y1 - 2004
A1 - J. M. Taylor
A1 - G. Giedke
A1 - H. Christ
A1 - B. Paredes
A1 - J. I. Cirac
A1 - P. Zoller
A1 - M. D. Lukin
A1 - A. Imamoglu
AB - We describe a technique for quantum information processing based on localized en sembles of nuclear spins. A qubit is identified as the presence or absence of a collective excitation of a mesoscopic ensemble of nuclear spins surrounding a single quantum dot. All single and two-qubit operations can be effected using hyperfine interactions and single-electron spin rotations, hence the proposed scheme avoids gate errors arising from entanglement between spin and orbital degrees of freedom. Ultra-long coherence times of nuclear spins suggest that this scheme could be particularly well suited for applications where long lived memory is essential.
UR - http://arxiv.org/abs/cond-mat/0407640v2
ER -
TY - JOUR
T1 - Controlling a mesoscopic spin environment by quantum bit manipulation
JF - Physical Review Letters
Y1 - 2003
A1 - J. M. Taylor
A1 - A. Imamoglu
A1 - M. D. Lukin
AB - We present a unified description of cooling and manipulation of a mesoscopic bath of nuclear spins via coupling to a single quantum system of electronic spin (quantum bit). We show that a bath cooled by the quantum bit rapidly saturates. Although the resulting saturated states of the spin bath (``dark states'') generally have low degrees of polarization and purity, their symmetry properties make them a valuable resource for the coherent manipulation of quantum bits. Specifically, we demonstrate that the dark states of nuclear ensembles can be used to coherently control the system-bath interaction and to provide a robust, long-lived quantum memory for qubit states.
VL - 91
UR - http://arxiv.org/abs/cond-mat/0308459v1
CP - 24
J1 - Phys. Rev. Lett.
U5 - 10.1103/PhysRevLett.91.246802
ER -