Parity-to-charge conversion in Majorana qubit readout

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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 [Kirsanskas, Franckie, and Wacker, Phys. Rev. B 97, 035432 (2018); Mozgunov and Lidar, Quantum 4, 227 (2020); Nathan and Rudner, arXiv:2004.01469], 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.

Original languageEnglish
Article number033254
JournalPhysical Review Research
Volume2
Issue number3
Number of pages19
DOIs
Publication statusPublished - 17 Aug 2020

    Research areas

  • NON-ABELIAN STATISTICS, P-WAVE, QUANTUM, NANOWIRE, FERMIONS, SUPERCONDUCTOR, STATES, SIGNATURE

ID: 255449435