Quantum state preparation using tensor networks

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openAccess

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Volume Title

A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä

Date

2023-07

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Mcode

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Language

en

Pages

12
1-12

Series

Quantum Science and Technology, Volume 8, issue 3

Abstract

Quantum state preparation is a vital routine in many quantum algorithms, including solution of linear systems of equations, Monte Carlo simulations, quantum sampling, and machine learning. However, to date, there is no established framework of encoding classical data into gate-based quantum devices. In this work, we propose a method for the encoding of vectors obtained by sampling analytical functions into quantum circuits that features polynomial runtime with respect to the number of qubits and provides > 99.9 % accuracy, which is better than a state-of-the-art two-qubit gate fidelity. We employ hardware-efficient variational quantum circuits, which are simulated using tensor networks, and matrix product state representation of vectors. In order to tune variational gates, we utilize Riemannian optimization incorporating auto-gradient calculation. Besides, we propose a ‘cut once, measure twice’ method, which allows us to avoid barren plateaus during gates’ update, benchmarking it up to 100-qubit circuits. Remarkably, any vectors that feature low-rank structure—not limited by analytical functions—can be encoded using the presented approach. Our method can be easily implemented on modern quantum hardware, and facilitates the use of the hybrid-quantum computing architectures.

Description

Funding Information: The work of Ar A M, A A T, F N, and M R P was supported by Terra Quantum A G. The work of S V D was financially supported by Terra Quantum A G through the consultancy agreement. Publisher Copyright: © 2023 The Author(s). Published by IOP Publishing Ltd

Keywords

quantum computing, quantum state preparation, Riemannian optimization, tensor networks, variational circuits

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Citation

Melnikov , A A , Termanova , A A , Dolgov , S V , Neukart , F & Perelshtein , M R 2023 , ' Quantum state preparation using tensor networks ' , Quantum Science and Technology , vol. 8 , no. 3 , 035027 , pp. 1-12 . https://doi.org/10.1088/2058-9565/acd9e7