TY - JOUR

T1 - Parity-to-charge conversion in Majorana qubit readout

AU - Munk, Morten I. K.

AU - Schulenborg, Jens

AU - Egger, Reinhold

AU - Flensberg, Karsten

PY - 2020/8/17

Y1 - 2020/8/17

N2 - 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.

AB - 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.

KW - NON-ABELIAN STATISTICS

KW - P-WAVE

KW - QUANTUM

KW - NANOWIRE

KW - FERMIONS

KW - SUPERCONDUCTOR

KW - STATES

KW - SIGNATURE

U2 - 10.1103/PhysRevResearch.2.033254

DO - 10.1103/PhysRevResearch.2.033254

M3 - Journal article

VL - 2

JO - Physical Review Research

JF - Physical Review Research

SN - 2643-1564

IS - 3

M1 - 033254

ER -