Mitigated barren plateaus in the time-nonlocal optimization of analog quantum-algorithm protocols

Fuente: arXiv
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Main Authors: Broers, Lukas, Mathey, Ludwig
Format: Preprint
Published: 2021
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author Broers, Lukas
Mathey, Ludwig
author_facet Broers, Lukas
Mathey, Ludwig
contents Quantum machine learning has emerged as a promising utilization of near-term quantum computation devices. However, algorithmic classes such as variational quantum algorithms have been shown to suffer from barren plateaus due to vanishing gradients in their parameters spaces. We present an approach to quantum algorithm optimization that is based on trainable Fourier coefficients of Hamiltonian system parameters. Our ansatz is exclusive to the extension of discrete quantum variational algorithms to analog quantum optimal control schemes and is non-local in time. We demonstrate the viability of our ansatz on the objectives of compiling the quantum Fourier transform and preparing ground states of random problem Hamiltonians. In comparison to the temporally local discretization ansätze in quantum optimal control and parameterized circuits, our ansatz exhibits faster and more consistent convergence. We uniformly sample objective gradients across the parameter space and find that in our ansatz the variance decays at a non-exponential rate with the number of qubits, while it decays at an exponential rate in the temporally local benchmark ansatz. This indicates the mitigation of barren plateaus in our ansatz. We propose our ansatz as a viable candidate for near-term quantum machine learning.
format Preprint
id arxiv_https___arxiv_org_abs_2111_08085
institution arXiv
publishDate 2021
record_format arxiv
spellingShingle Mitigated barren plateaus in the time-nonlocal optimization of analog quantum-algorithm protocols
Broers, Lukas
Mathey, Ludwig
Quantum Physics
Other Condensed Matter
Quantum machine learning has emerged as a promising utilization of near-term quantum computation devices. However, algorithmic classes such as variational quantum algorithms have been shown to suffer from barren plateaus due to vanishing gradients in their parameters spaces. We present an approach to quantum algorithm optimization that is based on trainable Fourier coefficients of Hamiltonian system parameters. Our ansatz is exclusive to the extension of discrete quantum variational algorithms to analog quantum optimal control schemes and is non-local in time. We demonstrate the viability of our ansatz on the objectives of compiling the quantum Fourier transform and preparing ground states of random problem Hamiltonians. In comparison to the temporally local discretization ansätze in quantum optimal control and parameterized circuits, our ansatz exhibits faster and more consistent convergence. We uniformly sample objective gradients across the parameter space and find that in our ansatz the variance decays at a non-exponential rate with the number of qubits, while it decays at an exponential rate in the temporally local benchmark ansatz. This indicates the mitigation of barren plateaus in our ansatz. We propose our ansatz as a viable candidate for near-term quantum machine learning.
title Mitigated barren plateaus in the time-nonlocal optimization of analog quantum-algorithm protocols
topic Quantum Physics
Other Condensed Matter
url https://arxiv.org/abs/2111.08085