Ultra-dispersive resonator readout of a quantum-dot qubit using longitudinal coupling

Demonstrates quantum-dot hybrid-qubit readout through a parametrically activated longitudinal interaction with a superconducting resonator.

Key Results

Operates with qubit-resonator detuning of roughly 10 GHz in an ultra-dispersive regime.
Uses state-dependent resonator response near the hybrid-qubit anticrossings.
Reconstructs the four-state double-dot Hamiltonian from spectroscopy and readout data.