Quantum computing with an electron spin ensemble.

We propose to encode a register of quantum bits in different collective electron spin wave excitations in a solid medium. Coupling to spins is enabled by locating them in the vicinity of a superconducting transmission line cavity, and making use of their strong collective coupling to the quantized radiation field. The transformation between different spin waves is achieved by applying gradient magnetic fields across the sample, while a Cooper pair box, resonant with the cavity field, may be used to carry out one- and two-qubit gate operations.

[1]  Klaus Mølmer,et al.  Holographic quantum computing. , 2008, Physical review letters.

[2]  R J Schoelkopf,et al.  Hybrid quantum processors: molecular ensembles as quantum memory for solid state circuits. , 2006, Physical review letters.

[3]  Mixed collective states of many spins , 2002, quant-ph/0201043.

[4]  A. Imamoğlu.  Cavity QED based on collective magnetic dipole coupling: spin ensembles as hybrid two-level systems. , 2008, Physical review letters.

[5]  Freeman J. Dyson,et al.  General Theory of Spin-Wave Interactions , 1956 .

[6]  C. Kittel,et al.  Dipolar Broadening of Magnetic Resonance Lines in Magnetically Diluted Crystals , 1953 .

[7]  L Frunzio,et al.  Approaching unit visibility for control of a superconducting qubit with dispersive readout. , 2005, Physical review letters.

[8]  C. Kittel,et al.  FERROMAGNETIC RELAXATION MECHANISM FOR Mz IN YTTRIUM IRON GARNET , 1960 .

[9]  John M Martinis,et al.  Magnetism in SQUIDs at millikelvin temperatures. , 2008, Physical review letters.

[10]  Eugene E. Haller,et al.  Solid-state quantum memory using the 31P nuclear spin , 2008, Nature.

[11]  C. Kittel,et al.  Ferromagnetic Relaxation Mechanism for M z in Yttrium Iron Garnet , 1960 .

[12]  S. A. Lyon,et al.  Electron spin relaxation times of phosphorus donors in silicon , 2003 .

[13]  P. Zoller,et al.  A coherent all-electrical interface between polar molecules and mesoscopic superconducting resonators , 2006 .

[14]  S. Kröll,et al.  Complete reconstruction of the quantum state of a single-photon wave packet absorbed by a Doppler-broadened transition. , 2001, Physical review letters.

[15]  E Knill,et al.  Efficient refocusing of one-spin and two-spin interactions for NMR quantum computation. , 1999, Journal of magnetic resonance.

[16]  Bradley A. Chase,et al.  Collective processes of an ensemble of spin- 1 ∕ 2 particles , 2008, 0805.2911.

[17]  Jian-Wei Pan,et al.  A millisecond quantum memory for scalable quantum networks , 2008, 0807.5064.

[18]  P. Callaghan.  Principles of Nuclear Magnetic Resonance Microscopy , 1991 .

[19]  I. Walmsley,et al.  Efficient spatially resolved multimode quantum memory , 2007, 0710.5033.

[20]  K. Mølmer,et al.  Quantum computing with a single molecular ensemble and a Cooper pair box , 2007, 0711.0606.

[21]  S. Girvin,et al.  Charge-insensitive qubit design derived from the Cooper pair box , 2007, cond-mat/0703002.

[22]  R. Rosenfeld.  Nature , 2009, Otolaryngology--head and neck surgery : official journal of American Academy of Otolaryngology-Head and Neck Surgery.

[23]  Field inside a random distribution of parallel dipoles. , 2004, Physical review letters.

[24]  S. Girvin,et al.  Strong coupling of a single photon to a superconducting qubit using circuit quantum electrodynamics , 2004, Nature.

[25]  M. Saffman,et al.  Scaling the neutral-atom Rydberg gate quantum computer by collective encoding in holmium atoms , 2008, 0805.0440.

[26]  Electron spin relaxation of N@C60 in CS2 in CS2. , 2005, The Journal of chemical physics.

[27]  J. Morton,et al.  Environmental effects on electron spin relaxation in N @ C 60 , 2006, quant-ph/0611108.

[28]  S. Girvin,et al.  Wiring up quantum systems , 2008, Nature.

[29]  B C Buchler,et al.  Photon echoes generated by reversing magnetic field gradients in a rubidium vapor. , 2008, Optics letters.

[30]  M. Saffman,et al.  Quantum computing with collective ensembles of multilevel systems. , 2007, Physical review letters.