Quantum Nondemolition Charge Measurement of a Josephson Qubit
arXiv:cond-mat/0412286 · doi:10.1103/PhysRevB.71.140505
Abstract
In a qubit system, the measurement operator does not necessarily commute with the qubit Hamiltonian, so that the readout process demolishes (mixes) the qubit energy eigenstates. The readout time is therefore limited by such a mixing time and its fidelity will be reduced. A quantum nondemolition readout scheme is proposed in which the charge of a flux qubit is measured. The measurement operator is shown to commute with the qubit Hamiltonian in the reduced two-level Hilbert space, even though the Hamiltonian contains non-commuting charge and flux terms.
4 pages, 3 figures, a paragraph added to describe how the scheme works in charge regime
References in corpus (6)
- Cavity quantum electrodynamics for superconducting electrical circuits: an architecture for quantum computation
- Coherent dynamics of a Josephson charge qubit
- Continuous Monitoring of Rabi Oscillations in a Josephson Flux Qubit
- Theory of weak continuous measurements in a strongly driven quantum bit
- Free Evolution of Superposition States in a Single Cooper Pair Box
- Flux Qubit in Charge-Phase Regime