Distributed inner product estimation with limited quantum communication

Fuente: arXiv
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Main Authors: Arunachalam, Srinivasan, Schatzki, Louis
Format: Preprint
Published: 2024
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author Arunachalam, Srinivasan
Schatzki, Louis
author_facet Arunachalam, Srinivasan
Schatzki, Louis
contents We consider the task of distributed inner product estimation when allowed limited quantum communication. Here, Alice and Bob are given $k$ copies of an unknown $n$-qubit quantum states $\vert ψ\rangle,\vert ϕ\rangle$ respectively. They are allowed to communicate $q$ qubits and unlimited classical communication, and their goal is to estimate $|\langle ψ|ϕ\rangle|^2$ up to constant accuracy. We show that $k=Θ(\sqrt{2^{n-q}})$ copies are essentially necessary and sufficient for this task (extending the work of Anshu, Landau and Liu (STOC'22) who considered the case when $q=0$). Additionally, we consider estimating $|\langle ψ|M|ϕ\rangle|^2$, for arbitrary Hermitian $M$. For this task we show that certain norms on $M$ characterize the sample complexity of estimating $|\langle ψ|M|ϕ\rangle|^2$ when using only classical~communication.
format Preprint
id arxiv_https___arxiv_org_abs_2410_12684
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Distributed inner product estimation with limited quantum communication
Arunachalam, Srinivasan
Schatzki, Louis
Quantum Physics
Computational Complexity
We consider the task of distributed inner product estimation when allowed limited quantum communication. Here, Alice and Bob are given $k$ copies of an unknown $n$-qubit quantum states $\vert ψ\rangle,\vert ϕ\rangle$ respectively. They are allowed to communicate $q$ qubits and unlimited classical communication, and their goal is to estimate $|\langle ψ|ϕ\rangle|^2$ up to constant accuracy. We show that $k=Θ(\sqrt{2^{n-q}})$ copies are essentially necessary and sufficient for this task (extending the work of Anshu, Landau and Liu (STOC'22) who considered the case when $q=0$). Additionally, we consider estimating $|\langle ψ|M|ϕ\rangle|^2$, for arbitrary Hermitian $M$. For this task we show that certain norms on $M$ characterize the sample complexity of estimating $|\langle ψ|M|ϕ\rangle|^2$ when using only classical~communication.
title Distributed inner product estimation with limited quantum communication
topic Quantum Physics
Computational Complexity
url https://arxiv.org/abs/2410.12684