Spontaneous recoherence of quantum states after decoherence |
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Authors: | M A?de?Ponte A?Cacheffo C J?Villas-B?as S S?Mizrahi M HY?Moussa |
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Institution: | (1) Department of Physics Blackett Laboratory, Imperial College London, Prince Consort Road, SW7 2BW London, UK;(2) Blackett Laboratory, Imperial College London, Prince Consort Road, SW7 2BW London, UK |
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Abstract: | In this work, we identify the set of time-dependent pure states building the
statistical mixture to which a system, initially in a pure state, is driven by
the reservoir. This set of time-dependent pure states, composing what we term
a pure basis, are those that diagonalize the reduced density operator
of the system. Next, we show that the evolution of the pure-basis
states reveals an interesting phenomenon as the system, after decoherence,
evolves toward the equilibrium: the spontaneous recoherence of quantum
states. Around our defined recoherence time, the statistical mixture
associated with a special kind of initial states termed even-symmetric,
spontaneously undergoes a recoherence process, by which the initial state of
the system emerges from the mixture except for its reduced excitation drained
into the reservoir. This phenomenon reveals that the reservoir only shuffle
the original information carried out by the initial state of the system
instead of erasing it. Moreover, as the spontaneously recohered state occurs
only for asymptotic time, we also present a protocol to extract it from the
mixture through specific projective measurements. The password to retrieve the
original information stems is the knowledge of both the initial state itself
and the associated pure basis. A definition of the decoherence time of
an N-state superposition is also presented. |
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Keywords: | |
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