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arXiv · 2004.02123

Parity-to-charge conversion in Majorana qubit readout

Morten I. K. Munk·Jens Schulenborg·Reinhold Egger·Karsten Flensberg
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Abstract

We study the time-dependent effect of Markovian readout processes on Majorana qubits whose parity degrees of freedom are converted into the charge of a tunnel-coupled quantum dot. By applying a recently established effective Lindbladian approximation [1-3], we obtain a completely positive and trace preserving Lindblad master equation for the combined dot-qubit dynamics, describing relaxation and decoherence processes beyond the rotating-wave approximation. This approach is applicable to a wide range of weakly coupled environments representing experimentally relevant readout devices. We study in detail the case of thermal decay in the presence of a generic Ohmic bosonic bath, in particular for potential fluctuations in an electromagnetic circuit. In addition, we consider the nonequilibrium measurement environment for a parity readout using a quantum point contact capacitively coupled to the dot charge.

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Morten I. K. Munk, Jens Schulenborg, Reinhold Egger, Karsten Flensberg. 2020-04-05. Parity-to-charge conversion in Majorana qubit readout. https://doi.org/10.1103/physrevresearch.2.033254

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