6 papers
Measurement-induced state transitions in multi-qubit transmon processors
Baptiste Hoyau, Alexander McDonald, Boris M. Varbanov +2
Dispersive readout of the transmon qubit in circuit QED is known to lose its quantum non-demolition character at small to moderate measurement drive amplitudes. This phenomenon is…
Measurement-induced state transitions across the fluxonium qubit landscape
Alex A. Chapple, Boris M. Varbanov, Alexander McDonald +1
Understanding the mechanisms that limit high-fidelity readout in circuit quantum electrodynamics is essential for its optimization. Multi-photon resonances are understood to be a l…
Robustness of longitudinal transmon readout to ionization
Alex A. Chapple, Alexander McDonald, Manuel H. Muñoz-Arias +1
Multi-photon processes deteriorate the quantum non-demolition (QND) character of the dispersive readout in circuit QED, causing readout to lag behind single and two-qubit gates, in…
Exponentially enhanced sensing through nonreciprocal light propagation
Paul-Ãdouard Blanchard, Alexander McDonald, Philippe St-Jean
Non-reciprocity is a key resource for pushing the performance of photonic devices beyond the fundamental limits imposed by Lorentz reciprocity. Here, we report on the realization o…
High-fidelity gates in a transmon using bath engineering for passive leakage reset
Ted Thorbeck, Alexander McDonald, O. Lanes +6
Leakage, the occupation of any state not used in the computation, is one of the of the most devastating errors in quantum error correction. Transmons, the most common superconducti…
Measurement-Induced Transmon Ionization
Marie Frédérique Dumas, Benjamin Groleau-Paré, Alexander McDonald +4
Despite the high measurement fidelity that can now be reached, the dispersive qubit readout of circuit quantum electrodynamics is plagued by a loss of its quantum nondemolition cha…