112 research outputs found
Landau-Zener interferometry for qubits
One may probe intrinsic coherence of a qubit by periodically sweeping its
control parameter. The qubit is then excited by Landau-Zener (LZ) mechanism.
The interference between multiple LZ transition leads to the unusual
oscillatory dependence of the energy absorption rate on sweeping amplitude and
period. This interference pattern allows to determine the decoherence time of
the qubit. We introduce a simple phenomenological model describing this
"interferometer", and find the form of the interference pattern.Comment: 7 pages, 2 figures; added: microscopic derivation of the master
equation, finite temperature of the reservoi
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