Optically Controlled Distributed Quantum Computing Using Atomic Ensembles As Qubits
Technical Report,15 Aug 2009,14 Aug 2015
NORTHWESTERN UNIV CHICAGO IL CHICAGO United States
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The goal of this project was to demonstrate the feasibility of realizing a large quantum computer by linking a series of elementary quantum computers EQCs, using ensembles of atoms as qubits. We built all the tools for making an EQC. However, experimental work revealed that use of light shift imbalance only is not enough to achieve the required blockade. We have now shown why this is the case, and have identified how the blockade can be restored by using Rydberg interaction assisted light-shift imbalance. However, due to lack of necessary lasers, we were unable to demonstrate the EQC using this scheme. Instead, we focused on exploring other aspects of collective state entanglement for precision metrology. Specifically, we have shown how to realize spin-squeezed collective state atomic interferometer COSAIN and collective state atomic clock COSAC, capable of improving the performance by a factor of root-N, thus reaching the Heisenberg limit. Significant experimental work has been carried out to demonstrate these devices, and this work will be carried to completion in the near future.