Automatic quantum circuit encoding of a given arbitrary quantum state

Fuente: arXiv
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Main Authors: Shirakawa, Tomonori, Ueda, Hiroshi, Yunoki, Seiji
Format: Preprint
Published: 2021
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author Shirakawa, Tomonori
Ueda, Hiroshi
Yunoki, Seiji
author_facet Shirakawa, Tomonori
Ueda, Hiroshi
Yunoki, Seiji
contents We propose a quantum-classical hybrid algorithm to encode a given arbitrarily quantum state $\vert Ψ\rangle$ onto an optimal quantum circuit $\hat{\mathcal{C}}$ with a finite number of single- and two-qubit quantum gates. The proposed algorithm employs as an objective function the absolute value of fidelity $F = \langle 0 \vert \hat{\mathcal{C}}^{\dagger} \vert Ψ\rangle$, which is maximized iteratively to construct an optimal quantum circuit $\hat{\mathcal{C}}$ with controlled accuracy. The key ingredient of the algorithm is the sequential determination of a set of optimal two-qubit unitary operators one by one via the singular value decomposition of the fidelity tensor. Once the optimal unitary operators are determined, including the location of qubits on which each unitary operator acts, elementary quantum gates are assigned algebraically. With noiseless numerical simulations, we demonstrate the algorithm to encode a ground state of quantum many-body systems, including the spin-1/2 antiferromagnetic Heisenberg model and the spin-1/2 XY model. The results are also compared with the quantum circuit encoding of the same quantum state onto a quantum circuit in a given circuit structure. Moreover, we demonstrate that the algorithm can also be applied to construct an optimal quantum circuit for classical data such as a classical image that is represented as a quantum state by the amplitude encoding. Finally, we also experimentally demonstrate that a quantum circuit generated by the AQCE algorithm can indeed represent the original quantum state reasonably on a noisy real quantum device.
format Preprint
id arxiv_https___arxiv_org_abs_2112_14524
institution arXiv
publishDate 2021
record_format arxiv
spellingShingle Automatic quantum circuit encoding of a given arbitrary quantum state
Shirakawa, Tomonori
Ueda, Hiroshi
Yunoki, Seiji
Quantum Physics
Statistical Mechanics
Strongly Correlated Electrons
We propose a quantum-classical hybrid algorithm to encode a given arbitrarily quantum state $\vert Ψ\rangle$ onto an optimal quantum circuit $\hat{\mathcal{C}}$ with a finite number of single- and two-qubit quantum gates. The proposed algorithm employs as an objective function the absolute value of fidelity $F = \langle 0 \vert \hat{\mathcal{C}}^{\dagger} \vert Ψ\rangle$, which is maximized iteratively to construct an optimal quantum circuit $\hat{\mathcal{C}}$ with controlled accuracy. The key ingredient of the algorithm is the sequential determination of a set of optimal two-qubit unitary operators one by one via the singular value decomposition of the fidelity tensor. Once the optimal unitary operators are determined, including the location of qubits on which each unitary operator acts, elementary quantum gates are assigned algebraically. With noiseless numerical simulations, we demonstrate the algorithm to encode a ground state of quantum many-body systems, including the spin-1/2 antiferromagnetic Heisenberg model and the spin-1/2 XY model. The results are also compared with the quantum circuit encoding of the same quantum state onto a quantum circuit in a given circuit structure. Moreover, we demonstrate that the algorithm can also be applied to construct an optimal quantum circuit for classical data such as a classical image that is represented as a quantum state by the amplitude encoding. Finally, we also experimentally demonstrate that a quantum circuit generated by the AQCE algorithm can indeed represent the original quantum state reasonably on a noisy real quantum device.
title Automatic quantum circuit encoding of a given arbitrary quantum state
topic Quantum Physics
Statistical Mechanics
Strongly Correlated Electrons
url https://arxiv.org/abs/2112.14524