Quarton couplers for ultrafast superconducting qubit readout: Part II, Experiment
ORAL
Abstract
Fast, high-fidelity, quantum nondemolition (QND) qubit readout is an essential tool for quantum information processing. In superconducting qubits, state-of-the-art readout is enabled by a dispersive cross-Kerr coupling between a qubit and its readout resonator. Although dispersive readout can be high-fidelity and QND, it is limited to ~50ns readout time by the ~10 MHz dispersive cross-Kerr. We previously proposed (Ye et al., PRL 2021) using quarton couplers to reach ultrastrong (~1 GHz) cross-Kerr between superconducting qubits and resonators. Here, we present a new superconducting qubit readout scheme exploiting the large qubit-resonator cross-Kerr enabled by quarton couplers. In part 1/2, we present the theoretical work on new quarton coupling physics and its realistic application to ultrafast readout. Full stochastic master equation simulations indicate that ultrafast readout times <5 ns with high (~99%) readout fidelity and QND-ness can be achieved. In part 2/2, we present early experimental work demonstrating the key properties of quarton coupling schemes including large cross-Kerr coupling and self-Kerr cancellation to linearize qubits into resonators suitable for readout.
*This research was funded in part by the ARO/LPS EMAQs program, the AWS Center for Quantum Computing, and the MIT Center for Quantum Engineering via support from the Laboratory for Physical Sciences under Contract No. H98230-19-C-0292. This material is based upon work supported under Air Force Contract No. FA8702-15-D-0001. Any opinions, findings, conclusions, or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the U.S. Air Force.
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Presenters
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Jeremy Kline
- Massachusetts Institute of Technology