Bonn 2000 – scientific programme

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Q: Quantenoptik

Q 37: Poster: Quanteninformation

Q 37.2: Poster

Thursday, April 6, 2000, 16:30–19:30, Aula

Speed of ion trap information processors — •Ferdinand Schmidt-Kaler¹, Christian Roos¹, Andreas Mundt¹, Dietrich Leibfried¹, Rainer Blatt¹, and Andrew Steane² — ¹Institut für Experimentalphysik, Universität Innsbruck, Austria — ²Centre for Quantum Computation, Clarendon Laboratory, Oxford, England

The combination of arbitrary driven unitary evolution, good scaling properties, and reliable measurement techniques of the resulting states are essential ingredients for a quantum information processor [1]. In this work we examine, both theoretically and experimentally, the maximum speed at which general operations can be driven in the ion trap system. Our aim is to clarify the trade-off between precision and speed of quantum logic gates, and to derive the optimal way to operate the processor.
We performed demonstration experiments using a single ground state cooled ⁴⁰Ca⁺ ion [2]. The basic gate operations involve electronic and vibrational excitation. Thus, we have driven a fast carrier and a fast sideband excitation. In the latter case, we reach Ω_Rabi=47kHz, hence we reach the regime of Ω_Rabi ≫ Ω_recoil, and observe indeed a reduced accuracy due to off-resonant carrier excitation. We fully understand the experimental findings and compare them with numerical simulations.

[1] J. I. Cirac and P. Zoller, Phys. Rev. Lett. 74, 4091 (1995)

[2] Ch. Roos, Th. Zeiger, H. Rohde, H. C. Nägerl, J. Eschner, D. Leibfried, F. Schmidt-Kaler, and R. Blatt, Phys. Rev. Lett. 83, 4713 (1999)