Anneal-path correction in flux qubits
- URL: http://arxiv.org/abs/2002.11217v2
- Date: Tue, 16 Feb 2021 18:57:11 GMT
- Title: Anneal-path correction in flux qubits
- Authors: Mostafa Khezri, Jeffrey A. Grover, James I. Basham, Steven M.
Disseler, Huo Chen, Sergey Novikov, Kenneth M. Zick, Daniel A. Lidar
- Abstract summary: Quantum annealers require accurate control and optimized operation schemes to reduce noise levels.
We study a high coherence four-junction capacitively shunted flux qubit (CSFQ)
- Score: 0.0
- License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
- Abstract: Quantum annealers require accurate control and optimized operation schemes to
reduce noise levels, in order to eventually demonstrate a computational
advantage over classical algorithms. We study a high coherence four-junction
capacitively shunted flux qubit (CSFQ), using dispersive measurements to
extract system parameters and model the device. Josephson junction asymmetry
inherent to the device causes a deleterious nonlinear cross-talk when annealing
the qubit. We implement a nonlinear annealing path to correct the asymmetry
in-situ, resulting in a substantial increase in the probability of the qubit
being in the correct state given an applied flux bias. We also confirm the
multi-level structure of our CSFQ circuit model by annealing it through small
spectral gaps and observing quantum signatures of energy level crossings. Our
results demonstrate an anneal-path correction scheme designed and implemented
to improve control accuracy for high-coherence and high-control quantum
annealers, which leads to an enhancement of success probability in annealing
protocols.
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