Fig. 1: Device design for interferometric fermion parity measurement.
From: Interferometric single-shot parity measurement in InAs–Al hybrid devices
a, Idealized model of the system. A nanowire tuned into a 1DTS state hosts MZMs at its ends, depicted by stars. A quantum dot is tunably coupled to the MZMs by tunnel couplings tL and tR, forming an interferometer, which is sensitive to the magnetic flux Φ enclosed by the dashed line and the combined fermion parity Z of the dot–MZMs system. Poisoning by a quasiparticle (purple circle) flips the parity. b, Example energy spectra of the interferometer with total parity Z = −1 (red) and Z = +1 (blue) in the vicinity of the avoided crossing between the states with N and N + 1 electrons on the dot, as a function of the plunger voltage on the quantum dot; see equation (2). c, Gate layout for the interference loop formed by the triple quantum dot and the gate-defined nanowire (light green). Voltage VWP1 is applied to the wire plunger gate (yellow) and voltage VQD2 is applied to the dot 2 plunger gate (purple). The effective couplings tL and tR of panel a depend on the couplings tm1, t12 and tm2, t23 and detuning of quantum dots 1 and 3, respectively. Quantum dot 2 is capacitively coupled to an off-chip resonator chip for dispersive gate sensing and CQ measurement, which also includes a bias tee for applying dc voltages.
