Engineering, control and longitudinal readout of Floquet qubits

Abstract

Properties of time-periodic Hamiltonians can be exploited to increase the dephasing time of qubits and to design protected one and two-qubit gates. Recently, Huang et al. [Phys. Rev. Applied 15, 034065 (2021)] have shown that time-dependent Floquet states offer a manifold of working points with dynamical protection larger than the few usual static sweet spots. Here, we use the framework of many-mode Floquet theory to describe approaches to robustly control Floquet qubits in the presence of multiple drive tones. Following the same approach, we introduce a longitudinal readout protocol to measure the Floquet qubit without the need of first adiabatically mapping back the Floquet states to the static qubit states, which results in a significant speedup in the measurement time of the Floquet qubit. The analytical approach developed here can be applied to any Hamiltonian involving a small number of distinct drive tones, typically the study of standard parametric gates for qubits outside of the rotating-wave approximation.

10 pages, 6 figures

References in corpus (4)

• Charge insensitive qubit design derived from the Cooper pair box
• QuTiP 2: A Python framework for the dynamics of open quantum systems
• Stroboscopic qubit measurement with squeezed illumination
• Flux control of superconducting qubits at dynamical sweet spots

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• Completely Positive Map for Noisy Driven Quantum Systems Derived by Keldysh Expansion
• Landau-Zener without a Qubit: Unveiling Multiphoton Interference, Synthetic Floquet Dimensions, and Dissipative Quantum Chaos
• Longitudinal coupling between electrically driven spin-qubits and a resonator
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• Theory of quasiparticle generation by microwave drives in superconducting qubits
• Optimization of Floquet fluxonium qubits with commensurable two-tone drives
• Floquet-engineered fast SNAP gates in weakly coupled circuit-QED systems
• Floquet Engineering Clock Transitions in Magnetic Molecules