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 …

The performance of a wide range of quantum computing algorithms and protocols depends
critically on the fidelity and speed of the employed qubit readout. Examples include gate …

Building a large-scale quantum computer requires effective strategies to correct errors that
inevitably arise in physical quantum systems. Quantum error-correction codes present a way …

The leakage of quantum information out of the two computational states of a qubit into other
energy states represents a major challenge for quantum error correction. During the …

Superconducting qubits are a promising platform for building fault-tolerant quantum
computers, with recent achievement showing the suppression of logical error with increasing …

The density of quasiparticles typically observed in superconducting qubits exceeds the
value expected in equilibrium by many orders of magnitude. Can this out-of-equilibrium …

Residual noise photons in a readout resonator become a major source of dephasing for a
superconducting qubit when the resonator is optimized for a fast, high-fidelity dispersive …

Minimizing leakage from computational states is a challenge when using many-level
systems like superconducting quantum circuits as qubits. We realize and extend the …

Quantum error correction with erasure qubits promises significant advantages over standard
error correction due to favorable thresholds for erasure errors. To realize this advantage in …

Cat qubits, for which logical| 0⟩ and| 1⟩ are coherent states|±α⟩ of a harmonic mode, offer
a promising route towards quantum error correction. Using dissipation to our advantage so …