Hannover 2003 – wissenschaftliches Programm

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Q: Quantenoptik

Q 13: Quantencomputer

Q 13.1: Vortrag

Montag, 24. März 2003, 16:30–16:45, F102

Quantum computation with cold atoms in an optical lattice — •Juan Jose Garcia-Ripoll and Juan Ignacio Cirac — M. P. I. für Quantenoptik, Hans-Kopfermann-Str, 1, Garching b. München, D-85748

In this talk we analyse an implementation of quantum computing using atoms confined in optical lattices. These systems have interesting features for computation: redundancy due to the large number of atoms which can be trapped, low temperatures and relatively slow decoherence. However, the same setups pose also important experimental challenges, such as being able to load the lattice with one atom per site or being able to measure the interaction and tunneling constants of these systems with high accuracy. These obstacles, together with the uncertainties in the atom-laser interaction, must be overcome to implement current proposals for quantum computing with neutral atoms.

We will analyse a way that solves the above mentioned problems and provides a very high gate fidelity even when most of the parameters describing the atomic ensemble (number of atoms per lattice site, tunneling rate, Rabi frequencies, etc) cannot be adjusted to precise values, and even have uncertainties of the order of the parameters themselves. Our method [1] combines the technique of adiabatic passage with ideas of quantum control theory. Basically, the experimental parameters which govern the system are adiabatically or abruptly in order to produce a controlled change in the system, while avoiding spurious dynamical and geometrical phases.

[1] García-Ripoll, J. J., Cirac, J. I., Phys. Rev. Lett. (submitted). arXiv:quant-ph/0208143.