Atomic ensemble mesoscopic

This part addresses mesoscopic systems as diverse as SQUIDS, Bose condensates, trapped atomic ensembles, electronic inerferometers and micromasers. It shows that coherence and entanglement can persist in such systems ... 

The frozen Rydberg gas corresponds to a quantum mesoscopic system, where the coherence of the two-level system is shared with the ensemble of the other atoms, offering an interesting example of decoherence through interaction with the environment [Joos 2003]. 

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