Variational learning algorithms for quantum query complexity

Fuente: arXiv
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Main Authors: Wu, Zipeng, Hou, Shi-Yao, Zhang, Chao, Li, Lvzhou, Zeng, Bei
Format: Preprint
Published: 2022
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author Wu, Zipeng
Hou, Shi-Yao
Zhang, Chao
Li, Lvzhou
Zeng, Bei
author_facet Wu, Zipeng
Hou, Shi-Yao
Zhang, Chao
Li, Lvzhou
Zeng, Bei
contents Quantum query complexity plays an important role in studying quantum algorithms, which captures the most known quantum algorithms, such as search and period finding. A query algorithm applies $U_tO_x\cdots U_1O_xU_0$ to some input state, where $O_x$ is the oracle dependent on some input variable $x$, and $U_i$s are unitary operations that are independent of $x$, followed by some measurements for readout. In this work, we develop variational learning algorithms to study quantum query complexity, by formulating $U_i$s as parameterized quantum circuits and introducing a loss function that is directly given by the error probability of the query algorithm. We apply our method to analyze various cases of quantum query complexity, including a new algorithm solving the Hamming modulo problem with $4$ queries for the case of $5$-bit modulo $5$, answering an open question raised in arXiv:2112.14682, and the result is further confirmed by a Semidefinite Programming (SDP) algorithm. Compared with the SDP algorithm, our method can be readily implemented on the near-term Noisy Intermediate-Scale Quantum (NISQ) devices and is more flexible to be adapted to other cases such as the fractional query models.
format Preprint
id arxiv_https___arxiv_org_abs_2205_07449
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Variational learning algorithms for quantum query complexity
Wu, Zipeng
Hou, Shi-Yao
Zhang, Chao
Li, Lvzhou
Zeng, Bei
Quantum Physics
Quantum query complexity plays an important role in studying quantum algorithms, which captures the most known quantum algorithms, such as search and period finding. A query algorithm applies $U_tO_x\cdots U_1O_xU_0$ to some input state, where $O_x$ is the oracle dependent on some input variable $x$, and $U_i$s are unitary operations that are independent of $x$, followed by some measurements for readout. In this work, we develop variational learning algorithms to study quantum query complexity, by formulating $U_i$s as parameterized quantum circuits and introducing a loss function that is directly given by the error probability of the query algorithm. We apply our method to analyze various cases of quantum query complexity, including a new algorithm solving the Hamming modulo problem with $4$ queries for the case of $5$-bit modulo $5$, answering an open question raised in arXiv:2112.14682, and the result is further confirmed by a Semidefinite Programming (SDP) algorithm. Compared with the SDP algorithm, our method can be readily implemented on the near-term Noisy Intermediate-Scale Quantum (NISQ) devices and is more flexible to be adapted to other cases such as the fractional query models.
title Variational learning algorithms for quantum query complexity
topic Quantum Physics
url https://arxiv.org/abs/2205.07449