Trapped atomic ions have been used successfully to demonstrate1 basic elements of universal quantum information processing. Nevertheless, scaling up such methods to achieve large-scale, universal quantum information processing (or more specialized quantum simulations2,3,4,5) remains challenging. The use of easily controllable and stable microwave sources, rather than complex laser systems6,7, could remove obstacles to scalability. However, the microwave approach has drawbacks: it involves the use of magnetic-field-sensitive states, which shorten coherence times considerably, and requires large, stable magnetic field gradients. Here we show how to overcome both problems by using stationary atomic quantum states as qubits that are induced by microwave fields (that is, by dressing magnetic-field-sensitive states with microwave fields). This permits fast quantum logic, even in the presence of a small (effective) Lamb–Dicke parameter (and, therefore, moderate magnetic field gradients). We experimentally demonstrate the basic building blocks of this scheme, showing that the dressed states are long lived and that coherence times are increased by more than two orders of magnitude relative to those of bare magnetic-field-sensitive states. This improves the prospects of microwave-driven ion trap quantum information processing, and offers a route to extending coherence times in all systems that suffer from magnetic noise, such as neutral atoms, nitrogen-vacancy centres, quantum dots or circuit quantum electrodynamic systems.
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Blatt, R. & Wineland, D. Entangled states of trapped atomic ions. Nature 453, 1008–1015 (2008)
Friedenauer, A. Schmitz, H. Glueckert, J. T., Porras, D. & Schaetz, T. Simulating a quantum magnet with trapped ions. Nature Phys. 4, 757–761 (2008)
Kim, K. et al. Quantum simulation of frustrated Ising spins with trapped ions. Nature 465, 590–593 (2010)
Gerritsma, R. et al. Quantum simulation of the Dirac equation. Nature 463, 68–71 (2010)
Johanning, M. Varón, A. F. & Wunderlich, C. Quantum simulations with cold trapped ions. J. Phys. B 42, 154009 (2009)
Mintert, F. & Wunderlich, C. Ion-trap quantum logic using long-wavelength radiation. Phys. Rev. Lett. 87, 257904 (2001)
Ospelkaus, C. et al. Trapped-ion quantum logic gates based on oscillating magnetic fields. Phys. Rev. Lett. 101, 090502 (2008)
Ozeri, R. et al. Errors in trapped-ion quantum gates due to spontaneous photon scattering. Phys. Rev. A 75, 042329 (2007)
Plenio, M. B. & Knight, P. L. Decoherence limits to quantum computation using trapped ions. Proc. R. Soc. Lond. A 453, 2017–2041 (1997)
Sørensen, A. & Mølmer, K. Entanglement and quantum computation with ions in thermal motion. Phys. Rev. A 62, 022311 (2000)
Milburn, G. J. Schneider, S. & James, D. F. V. Ion trap quantum computing with warm ions. Fortschr. Phys. 48, 801–810 (2000)
Wunderlich, C. in Laser Physics at the Limit (eds Meschede, D., Zimmermann, C. & Figger, H. ) 261–271 (Springer, 2002)
Wunderlich, C. & Balzer, C. Quantum measurements and new concepts for experiments with trapped ions. Adv. At. Mol. Phys. 49, 293–372 (2003)
Mc Hugh, D. & Twamley, J. Quantum computer using a trapped-ion spin molecule and microwave radiation. Phys. Rev. A 71, 012315 (2005)
Wang, S. X. Labaziewicz, J. Ge, Y., Shewmon, R. & Chuang, I. L. Individual addressing of ions using magnetic field gradients in a surface-electrode ion trap. Appl. Phys. Lett. 94, 094103 (2009)
Johanning, M. et al. Individual addressing of trapped ions and coupling of motional and spin states using RF radiation. Phys. Rev. Lett. 102, 073004 (2009)
Häffner, H. et al. Robust entanglement. Appl. Phys. B 81, 151–153 (2005)
Kielpinski, D. et al. A decoherence-free quantum memory using trapped ions. Science 291, 1013–1015 (2001)
Home, J. P. et al. Complete methods set for scalable ion trap quantum information processing. Science 325, 1227–1230 (2009)
Viola, L. & Lloyd, S. Dynamical suppression of decoherence in two-state quantum systems. Phys. Rev. A 58, 2733–2744 (1998)
Rabl, P. et al. Strong magnetic coupling between an electronic spin qubit and a mechanical resonator. Phys. Rev. B 79, 041302 (2009)
Biercuk, M. J. et al. Optimized dynamical decoupling in a model quantum memory. Nature 458, 996–1000 (2009)
Bluhm, H. et al. Dephasing time of GaAs electron-spin qubits coupled to a nuclear bath exceeding 200 μs. Nature Phys. 7, 109–113 (2011)
Vitanov, N. V. Fleischhauer, M. Shore, B. W. & Bergmann, K. Coherent manipulation of atoms and molecules by sequential laser pulses. Adv. At. Mol. Phys. 46, 55–190 (2001)
Sørensen, J. et al. Efficient coherent internal state transfer in trapped ions using stimulated Raman adiabatic passage. New J. Phys. 8, 261 1–11. (2006)
Cirac, J. I. & Zoller, P. Quantum computations with cold trapped ions. Phys. Rev. Lett. 74, 4091–4094 (1995)
Specht, H. P. et al. A single-atom quantum memory. Nature 473, 190–192 (2011)
Simon, C. et al. Quantum memories. Eur. Phys. J. D 58, 1–22 (2010)
Clarke, J. & Wilhelm, F. K. Superconducting quantum bits. Nature 453, 1031–1042 (2008)
Hannemann, T. et al. Self-learning estimation of quantum states. Phys. Rev. A 65, 050303 1–4. (2002)
Technical help with the microwave set-up by T. F. Gloger is acknowledged. We acknowledge support by the Bundesministerium für Bildung und Forschung (FK 01BQ1012 and P3352014), the Deutsche Forschungsgemeinschaft, the European Commission under the STREP PICC, the German-Israeli Foundation, secunet AG and the Alexander von Humboldt Foundation.
The authors declare no competing financial interests.
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Timoney, N., Baumgart, I., Johanning, M. et al. Quantum gates and memory using microwave-dressed states. Nature 476, 185–188 (2011). https://doi.org/10.1038/nature10319
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