A simple lower bound for the complexity of estimating partition functions on a quantum computer

Fuente: arXiv
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Auteurs principaux: Chen, Zherui, Nannicini, Giacomo
Format: Preprint
Publié: 2024
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author Chen, Zherui
Nannicini, Giacomo
author_facet Chen, Zherui
Nannicini, Giacomo
contents We study the complexity of estimating the partition function $\mathsf{Z}(β)=\sum_{x\inχ} e^{-βH(x)}$ for a Gibbs distribution characterized by the Hamiltonian $H(x)$. We provide a simple and natural lower bound for quantum algorithms that solve this task by relying on reflections through the coherent encoding of Gibbs states. Our primary contribution is a $\varOmega(1/ε)$ lower bound for the number of reflections needed to estimate the partition function with a quantum algorithm. The proof is based on a reduction from the problem of estimating the Hamming weight of an unknown binary string.
format Preprint
id arxiv_https___arxiv_org_abs_2404_02414
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle A simple lower bound for the complexity of estimating partition functions on a quantum computer
Chen, Zherui
Nannicini, Giacomo
Quantum Physics
Computational Complexity
Data Structures and Algorithms
Statistics Theory
We study the complexity of estimating the partition function $\mathsf{Z}(β)=\sum_{x\inχ} e^{-βH(x)}$ for a Gibbs distribution characterized by the Hamiltonian $H(x)$. We provide a simple and natural lower bound for quantum algorithms that solve this task by relying on reflections through the coherent encoding of Gibbs states. Our primary contribution is a $\varOmega(1/ε)$ lower bound for the number of reflections needed to estimate the partition function with a quantum algorithm. The proof is based on a reduction from the problem of estimating the Hamming weight of an unknown binary string.
title A simple lower bound for the complexity of estimating partition functions on a quantum computer
topic Quantum Physics
Computational Complexity
Data Structures and Algorithms
Statistics Theory
url https://arxiv.org/abs/2404.02414