Fast, High-Fidelity Addressed Single-Qubit Gates Using Efficient Composite Pulse Sequences.
Physical review letters 131:12 (2023) 120601
Abstract:
We use electronic microwave control methods to implement addressed single-qubit gates with high speed and fidelity, for ^{43}Ca^{+} hyperfine "atomic clock" qubits in a cryogenic (100 K) surface trap. For a single qubit, we benchmark an error of 1.5×10^{-6} per Clifford gate (implemented using 600 ns π/2 pulses). For 2 qubits in the same trap zone (ion separation 5 μm), we use a spatial microwave field gradient, combined with an efficient four-pulse scheme, to implement independent addressed gates. Parallel randomized benchmarking on both qubits yields an average error 3.4×10^{-5} per addressed π/2 gate. The scheme scales theoretically to larger numbers of qubits in a single register.Data for "Cryogenic ion trap system for high-fidelity near-field microwave-driven quantum logic"
University of Oxford (2023)
Abstract:
Datasets used to generate the figures of "Cryogenic ion trap system for high-fidelity near-field microwave-driven quantum logic", accepted for publication in "Quantum Science and Technology"Cryogenic ion trap system for high-fidelity near-field microwave-driven quantum logic
ArXiv 2207.11364 (2022)
Phonon-number resolution of voltage-biased mechanical oscillators with weakly-anharmonic superconducting circuits
Phys. Rev. A 104 (2021) 053509-053509
Abstract:
Observing quantum phenomena in macroscopic objects, and the potential discovery of a fundamental limit in the applicability of quantum mechanics, has been a central topic of modern experimental physics. Highly coherent and heavy micro-mechanical oscillators controlled by superconducting circuits are a promising system for this task. Here, we focus in particular on the electrostatic coupling of motion to a weakly anharmonic circuit, namely the transmon qubit. In the case of a megahertz mechanical oscillator coupled to a gigahertz transmon, we explain the difficulties in bridging the large electro-mechanical frequency gap. To remedy this issue, we explore the requirements to reach phonon-number resolution in the resonant coupling of a megahertz transmon and a mechanical oscillator.Corrigendum: QuCAT: quantum circuit analyzer tool in Python (2020 New J. Phys. 22 013025)
New Journal of Physics IOP Publishing 23:10 (2021) 109501