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Q: Quantenoptik und Photonik

Q 40: Quanteninformation III

Q 40.5: Vortrag

Mittwoch, 15. März 2006, 12:10–12:25, HI

A realistic quantum gate on an atom chip — •Philipp Treutlein¹, Antonio Negretti², Tommaso Calarco², Theodor W. Hänsch¹, and Jakob Reichel³ — ¹Max-Planck-Institut für Quantenoptik and LMU München, Germany — ²ECT* and Universita di Trento, Trento, Italy — ³Laboratoire Kaster Brossel de l’ENS, Paris, France

We propose a realistic scheme for a quantum gate on an atom chip and discuss the progress of our experiment towards its realization. In contrast to previous proposals [1], the qubit is encoded in two hyperfine states of ⁸⁷Rb with a very long coherence lifetime. The quantum phase gate is implemented by state-selective collisions of two qubit atoms in a state-selective potential. This scheme allows for gate operation times below one millisecond, more than three orders of magnitude shorter than the experimentally demonstrated coherence lifetime of the qubit [2]. A crucial role is played by microwave fields guided on the atom chip, which generate the state-selective potential for the atoms. We present a simulation of the gate performance in a realistic potential and show that high fidelity gate operations are possible, taking a large number of error sources into account. On the experimental side, we discuss the chip fabrication, show measurements of the propagation characteristics of the microwave guiding structures on the chip, and present the current status of our experiment.

[1] T. Calarco et al., Phys. Rev. A 61, 022304 (2000).

[2] Ph. Treutlein et al., Phys. Rev. Lett. 92, 203005 (2004).