A single hole spin in a semiconductor quantum dot has emerged as a quantum bit that is potentially superior to an electron spin. A key feature of holes is that they have a greatly reduced hyperfine interaction with nuclear spins, which is one of the biggest difficulties in working with an electron spin. It is now essential to show that holes are viable for quantum information processing by demonstrating fast quantum gates and scalability. To this end, we have developed InAs/GaAs quantum dots coupled through coherent tunnelling and charged with controlled numbers of holes. We report fast, single-qubit gates using a sequence of short laser pulses. We then take the important next step towards scalability of quantum information by optically controlling two interacting hole spins in separate dots.
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Englund, D., Faraon, A., Zhang, B., Yamamoto, Y. & Vuckovic, J. Generation and transfer of single photons on a photonic chip. Opt. Express 15, 5550–5558 (2007).
Berezovsky, J., Mikkelson, M. H., Stoltz, N. G., Coldren, L. A. & Awschalom, D. D. Picosecond coherent optical manipulation of a single electron spin in a quantum dot. Science 320, 349–352 (2008).
Press, D., Ladd, T. D., Zhang, B. & Yamamoto, Y. Complete quantum control of a single quantum dot spin using ultrafast optical pulses. Nature 456, 218–221 (2008).
Greilich, A. et al. Ultrafast optical rotations of electron spins in quantum dots. Nature Phys. 5, 262–266 (2009).
Kim, E. D. et al. Fast spin rotations by optically controlled geometric phases in a charge-tunable InAs quantum dot. Phys. Rev. Lett. 104, 167401 (2010).
Press, D. et al. Ultrafast optical spin echo in a single quantum dot. Nature Photon. 4, 367–370 (2010).
de Vasconcellos, S. M., Gordon, S., Bichler, M., Meier, T. & Zrenner, A. Coherent control of a single exciton qubit. Nature Photon. 4, 545–548 (2010).
Kim, D., Carter, S. G., Greilich, A., Bracker, A. S. & Gammon, D. Ultrafast optical control of entanglement between two quantum-dot spins. Nature Phys. 7, 223–229 (2011).
Heiss, D. et al. Observation of extremely slow hole spin relaxation in self-assembled quantum dots. Phys. Rev. B 76, 241306(R) (2007).
Gerardot, B. D. et al. Optical pumping of a single hole spin in a quantum dot. Nature 451, 441–444 (2008).
Brunner, D. et al. A coherent single-hole spin in a semiconductor. Science 325, 70–72 (2009).
Merkulov, I. A., Efros, A. L. & Rosen, M. Electron spin relaxation by nuclei in semiconductor quantum dots. Phys. Rev. B 65, 205309 (2002).
Greilich, A. et al. Mode locking of electron spin coherences in singly charged quantum dots. Science 313, 341–345 (2006).
Petta, J. R. et al. Coherent manipulation of coupled electron spins in semiconductor quantum dots. Science 309, 2180–2184 (2005).
Fischer, J., Coish, W. A., Bulaev, D. V. & Loss, D. Spin decoherence of a heavy hole coupled to nuclear spins in a quantum dot. Phys. Rev. B 78, 155329 (2008).
Fischer, J. & Loss, D. Hybridization and spin decoherence in heavy-hole quantum dots. Phys. Rev. Lett. 105, 266603 (2010).
Eble, B. et al. Hole–nuclear spin interaction in quantum dots. Phys. Rev. Lett. 102, 146601 (2009).
Fallahi, P., Yilmaz, S. T. & Imamoglu, A. Measurement of a heavy-hole hyperfine interaction in InGaAs quantum dots using resonance fluorescence. Phys. Rev. Lett. 105, 257402 (2010).
Chekhovich, E. A., Krysa, A. B., Skolnick, M. S. & Tartakovskii, A. I. Direct measurement of the hole–nuclear spin interaction in single InP/GaInP quantum dots using photoluminescence spectroscopy. Phys. Rev. Lett. 106, 027402 (2011).
Winkler, R. Spin–Orbit Coupling Effects in Two-Dimensional Electron and Hole Systems (Springer-Verlag, 2003).
Bayer, M. et al. Fine structure of neutral and charged excitons in self-assembled In(Ga)As/(Al)GaAs quantum dots. Phys. Rev. B 65, 195315 (2002).
Doty, M. F. et al. Electrically tunable g factors in quantum dot molecular spin states. Phys. Rev. Lett. 97, 197202 (2006).
Andlauer, T. & Vogl, P. Electrically controllable g tensors in quantum dot molecules. Phys. Rev. B 79, 045307 (2009).
Doty, M. F. et al. Antibonding ground states in InAs quantum-dot molecules. Phys. Rev. Lett. 102, 047401 (2009).
Kavokin, K. Symmetry of anisotropic exchange interactions in semiconductor nanostructures. Phys. Rev. B 69, 075302 (2004).
Scheibner, M., Bracker, A. S., Kim, D. & Gammon, D. Essential concepts in the optical properties of quantum dot molecules. Solid State Commun. 149, 1427–1435 (2009).
Stinaff, E. A. et al. Optical signatures of coupled quantum dots. Science 311, 636–639 (2006).
Krenner, H. J. et al. Optically probing spin and charge interactions in a tunable artificial molecule. Phys. Rev. Lett. 97, 076403 (2006).
Doty, M. F. et al. Optical spectra of doubly charged quantum dot molecules in electric and magnetic fields. Phys. Rev. B 78, 115316 (2008).
Atature, M. et al. Quantum-dot spin-state preparation with near-unity fidelity. Science 312, 551–553 (2006).
Xu, X. et al. Fast spin state initialization in a singly charged InAs–GaAs quantum dot by optical cooling. Phys. Rev. Lett. 99, 097401 (2007).
Kim, D. et al. Optical spin initialization and nondestructive measurement in a quantum dot molecule. Phys. Rev. Lett. 101, 236804 (2008).
Vamivakas, A. N. et al. Observation of spin-dependent quantum jumps via quantum dot resonance fluorescence. Nature 467, 297–300 (2010).
Ladd, T. D. et al. Pulsed nuclear pumping and spin diffusion in a single charged quantum dot. Phys. Rev. Lett. 105, 107401 (2010).
Xu, X. et al. Optically controlled locking of the nuclear field via coherent dark-state spectroscopy. Nature 459, 1105–1109 (2009).
Latta, C. et al. Confluence of resonant laser excitation and bidirectional quantum-dot nuclear-spin polarization. Nature Phys. 5, 758–763 (2009).
Bracker, A. S. et al. Engineering electron and hole tunneling with asymmetric InAs quantum dot molecules. Appl. Phys. Lett. 89, 233110 (2006).
Calarco, T., Datta, A., Fedichev, P., Pazy, E. & Zoller, P. Spin-based all-optical quantum computation with quantum dots: understanding and suppressing decoherence. Phys. Rev. A 68, 012310 (2003).
Emary, C. & Sham, L. J. Optically controlled logic gates for two spin qubits in vertically coupled quantum dots. Phys. Rev. B 75, 125317 (2007).
Economou, S. E. & Reinecke, T. L. Optically induced spin gates in coupled quantum dots using the electron–hole exchange interaction. Phys. Rev. B 78, 115306 (2008).
De Greve, K. et al. Ultrafast coherent control and suppressed nuclear feedback of a single quantum dot hole qubit. Nature Phys. http://dx.doi.org/10.1038/nphys2078 (2011)
Godden, T. M. et al. Coherent optical control of the spin of a single hole in a quantum dot. Preprint at arXiv:1106.6282.
Greilich, A. et al. Nuclei-induced frequency focusing of electron spin coherence. Science 317, 1896–1899 (2007).
Doty, M. F. et al. Hole–spin mixing in InAs quantum dot molecules. Phys. Rev. B 81, 035308 (2010).
This work was supported by a Multi-University Research Initiative (US Army Research Office; W911NF0910406) and the US Office of Naval Research.
The authors declare no competing financial interests.
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Greilich, A., Carter, S., Kim, D. et al. Optical control of one and two hole spins in interacting quantum dots. Nature Photon 5, 702–708 (2011). https://doi.org/10.1038/nphoton.2011.237
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