Abstract
We present a method to improve the convergence of variational algorithms based on hidden inverses (HIs) to mitigate coherent errors. In the context of error mitigation, this means replacing the hardware implementation of certain Hermitian gates with their inverses. Doing so results in noise cancellation and a more resilient quantum circuit. This approach improves performance in a variety of two-qubit error models where the noise operator also inverts with the gate inversion. We apply the mitigation scheme on superconducting quantum processors running the variational quantum eigensolver (VQE) algorithm to find the H 2 ground-state energy. When implemented on superconducting hardware we find that the mitigation scheme effectively reduces the energy fluctuations in the parameter learning path in VQE, reducing the number of iterations for a converged value. We also provide a detailed numerical simulation of VQE performance under different noise models and explore how HIs and randomized compiling affect the underlying loss landscape of the learning problem. These simulations help explain our experimental hardware outcomes, helping to connect lower-level gate performance to application-specific behavior in contrast to metrics like fidelity which often do not provide an intuitive insight into observed high level performance.
Original language | English |
---|---|
Article number | 014008 |
Journal | Quantum Science and Technology |
Volume | 8 |
Issue number | 1 |
DOIs | |
State | Published - Jan 2023 |
Funding
Authors thank Kenneth Brown for helpful discussions. This work was supported as part of the ASCR Quantum Testbed Pathfinder Program at Oak Ridge National Laboratory under FWP # ERKJ332. S M was supported through US Department of Energy Grant No. DE-SC0019294 awarded to Duke and is funded in part by an NSF QISE-NET fellowship (1747426). This research used resources of the Oak Ridge Leadership Computing Facility, which is a DOE Office of Science User Facility supported under Contract No. DE-AC05-00OR22725.
Keywords
- coherent noise mitigation
- error mitigation
- ground state estimation
- quantum chemistry
- superconducting qubits
- variational quantum eigensolver