Photonic Qubit and Nuclear Qubit for Quantum Information Systems
Yoshihisa Yamamoto (Stanford Univ.)


Novel nonclassical light, indistinguishable single photons and entangled photons are generated on demand with a single quantum dot microvacity device [1] [2] and successfully applied to quantum key distribution systems [3][4] and fundamental test of quantum mechanics. The system replacing a quantum dot with an ensemble of impurities is expected to realize efficient quantum memory and quantum repeater systems. Optical pumping and optical detection of nuclear spins in solids are studied toward realization of a large-scale solid state NMR quantum computer. [5][6] Preliminary results are encouraging in terms of high nuclear polarization and long decoherence time.


[1] C. Santori, M. Pelton, G. S. Solomon, Y. Dale, and Y. Yamamoto. Triggered Single Photons from a Quantum Dot. Phys. Rev. Lett., 86: 1502-1505, 2001.

[2] C. Santori, D. Fattal, J. Vuckovic, G. S. Solomon, and Y. Yamamoto. Indistinguishable photons from a singlephoton device. Nature, 419: 594-597, 2002.

[3] K. Inoue, E. Waks, and Y. Yamamoto. Differential Phase Shift Quantum Key Distribution. Phys. Rev. Lett. , 89: 037902-1 - 037902-3, 2002.

[4] E. Waks, K. Inoue, C. Santori, D. Fattal, J. Vuckovic, G. S. Solomon, and Y. Yamamoto. Quantum cryptography with a photon turnstile. Nature, 420: 762, 2002.

[5] T. D. Ladd, J. R. Goldman, F. Yamaguchi, Y. Yamamoto, E. Abe, and K. M. Itoh. All-Silicon Quantum Computer. Phys. Rev. Lett., 89: 017901-1 - 017901-4, 2002.

[6] C. P. Master, F. Yamaguchi, and Y. Yamamoto. Efficiency of Free Energy Calculations of Spin Lattices by Spectral Quantum Algorithms. Phys. Rev.A, 67: 032311-1 - 032311-9, 2003.

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