Universal decoherence induced by an environmental quantum phase transition

Decoherence induced by coupling a system with an environment may display universal features. We demonstrate that when the coupling to the system drives a quantum phase transition in the environment, the decay of quantum coherences in the system is Gaussian with a width independent of the system-envi...

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Autores principales: Cucchietti, F.M., Fernandez-Vidal, S., Paz, J.P.
Formato: JOUR
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Acceso en línea:http://hdl.handle.net/20.500.12110/paper_10502947_v75_n3_p_Cucchietti
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Sumario:Decoherence induced by coupling a system with an environment may display universal features. We demonstrate that when the coupling to the system drives a quantum phase transition in the environment, the decay of quantum coherences in the system is Gaussian with a width independent of the system-environment coupling strength. We obtain analytical results for a class of solvable models, and present numerical evidence supporting the validity of our results in more general cases. This effect opens the way for a quantum simulation algorithm, where a single qubit is used to detect a quantum phase transition. We discuss possible implementations of such an algorithm and relate our results to available data on universal decoherence in NMR echo experiments. © 2007 The American Physical Society.