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Abstract:

We theoretically study specific schemes for performing a fundamental two-qubit quantum gate via controlled atomic collisions by switching microscopic potentials. In particular we calculate the fidelity of a gate operation for a configuration where a potential barrier between two atoms is instantaneously removed and restored after a certain time. Possible implementations could be based on microtraps created by magnetic and electric fields, or potentials induced by laser light.

Abstract:

Controlled cold collisions of atoms in optical lattices allow implementation of highly parallel entanglement operation and quantum gates. Applications include quantum computing with efficient quantum error correction. The use of cold controlled collisions of atoms, trapped in the ground state of the lattice wells, a mechanism to introduce dynamic phase shifts depending on the state of the atoms is proposed. In lattices with ordered filling structures, highly parallel entanglement operations could be implemented, corresponding to a novel class of quantum gates. These multi-qubit quantum gates can be employed for efficient quantum error correction. How the parallelism in an optical lattice could be used for quantum computation in general is discussed.