Hierarchical Multigrid Ansatz for Variational Quantum Algorithms

Fuente: arXiv
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Auteurs principaux: Keller, Christo Meriwether, Eidenbenz, Stephan, Bärtschi, Andreas, O'Malley, Daniel, Golden, John, Misra, Satyajayant
Format: Preprint
Publié: 2023
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author Keller, Christo Meriwether
Eidenbenz, Stephan
Bärtschi, Andreas
O'Malley, Daniel
Golden, John
Misra, Satyajayant
author_facet Keller, Christo Meriwether
Eidenbenz, Stephan
Bärtschi, Andreas
O'Malley, Daniel
Golden, John
Misra, Satyajayant
contents Quantum computing is an emerging topic in engineering that promises to enhance supercomputing using fundamental physics. In the near term, the best candidate algorithms for achieving this advantage are variational quantum algorithms (VQAs). We design and numerically evaluate a novel ansatz for VQAs, focusing in particular on the variational quantum eigensolver (VQE). As our ansatz is inspired by classical multigrid hierarchy methods, we call it "multigrid" ansatz. The multigrid ansatz creates a parameterized quantum circuit for a quantum problem on $n$ qubits by successively building and optimizing circuits for smaller qubit counts $j < n$, reusing optimized parameter values as initial solutions to next level hierarchy at $j+1$. We show through numerical simulation that the multigrid ansatz outperforms the standard hardware-efficient ansatz in terms of solution quality for the Laplacian eigensolver as well as for a large class of combinatorial optimization problems with specific examples for MaxCut and Maximum $k$-Satisfiability. Our studies establish the multi-grid ansatz as a viable candidate for many VQAs and in particular present a promising alternative to the QAOA approach for combinatorial optimization problems.
format Preprint
id arxiv_https___arxiv_org_abs_2312_15048
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Hierarchical Multigrid Ansatz for Variational Quantum Algorithms
Keller, Christo Meriwether
Eidenbenz, Stephan
Bärtschi, Andreas
O'Malley, Daniel
Golden, John
Misra, Satyajayant
Quantum Physics
Emerging Technologies
Quantum computing is an emerging topic in engineering that promises to enhance supercomputing using fundamental physics. In the near term, the best candidate algorithms for achieving this advantage are variational quantum algorithms (VQAs). We design and numerically evaluate a novel ansatz for VQAs, focusing in particular on the variational quantum eigensolver (VQE). As our ansatz is inspired by classical multigrid hierarchy methods, we call it "multigrid" ansatz. The multigrid ansatz creates a parameterized quantum circuit for a quantum problem on $n$ qubits by successively building and optimizing circuits for smaller qubit counts $j < n$, reusing optimized parameter values as initial solutions to next level hierarchy at $j+1$. We show through numerical simulation that the multigrid ansatz outperforms the standard hardware-efficient ansatz in terms of solution quality for the Laplacian eigensolver as well as for a large class of combinatorial optimization problems with specific examples for MaxCut and Maximum $k$-Satisfiability. Our studies establish the multi-grid ansatz as a viable candidate for many VQAs and in particular present a promising alternative to the QAOA approach for combinatorial optimization problems.
title Hierarchical Multigrid Ansatz for Variational Quantum Algorithms
topic Quantum Physics
Emerging Technologies
url https://arxiv.org/abs/2312.15048