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Autori principali: Danz, Sven, Berta, Mario, Schröder, Stefan, Kienast, Pascal, Wilhelm, Frank K., Ciani, Alessandro
Natura: Preprint
Pubblicazione: 2024
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Accesso online:https://arxiv.org/abs/2405.08694
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author Danz, Sven
Berta, Mario
Schröder, Stefan
Kienast, Pascal
Wilhelm, Frank K.
Ciani, Alessandro
author_facet Danz, Sven
Berta, Mario
Schröder, Stefan
Kienast, Pascal
Wilhelm, Frank K.
Ciani, Alessandro
contents We study the problem of estimating frequency response functions of systems of coupled, classical harmonic oscillators using a quantum computer. The functional form of these response functions can be mapped to a corresponding eigenproblem of a Hermitian matrix $H$, thus suggesting the use of quantum phase estimation. Our proposed quantum algorithm operates in the standard $s$-sparse, oracle-based query access model. For a network of $N$ oscillators with maximum norm $\lVert H \rVert_{\mathrm{max}}$, and when the eigenvalue tolerance $\varepsilon$ is much smaller than the minimum eigenvalue gap, we use $\mathcal{O}(\log(N s \lVert H \rVert_{\mathrm{max}}/\varepsilon)$ algorithmic qubits and obtain a rigorous worst-case query complexity upper bound $\mathcal{O}(s \lVert H \rVert_{\mathrm{max}}/(δ^2 \varepsilon) )$ up to logarithmic factors, where $δ$ denotes the desired precision on the coefficients appearing in the response functions. Crucially, our proposal does not suffer from the infamous state preparation bottleneck and can as such potentially achieve large quantum speedups compared to relevant classical methods. As a proof-of-principle of exponential quantum speedup, we show that a simple adaptation of our algorithm solves the random glued-trees problem in polynomial time. We discuss practical limitations as well as potential improvements for quantifying finite size, end-to-end complexities for application to relevant instances.
format Preprint
id arxiv_https___arxiv_org_abs_2405_08694
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Calculating response functions of coupled oscillators using quantum phase estimation
Danz, Sven
Berta, Mario
Schröder, Stefan
Kienast, Pascal
Wilhelm, Frank K.
Ciani, Alessandro
Quantum Physics
We study the problem of estimating frequency response functions of systems of coupled, classical harmonic oscillators using a quantum computer. The functional form of these response functions can be mapped to a corresponding eigenproblem of a Hermitian matrix $H$, thus suggesting the use of quantum phase estimation. Our proposed quantum algorithm operates in the standard $s$-sparse, oracle-based query access model. For a network of $N$ oscillators with maximum norm $\lVert H \rVert_{\mathrm{max}}$, and when the eigenvalue tolerance $\varepsilon$ is much smaller than the minimum eigenvalue gap, we use $\mathcal{O}(\log(N s \lVert H \rVert_{\mathrm{max}}/\varepsilon)$ algorithmic qubits and obtain a rigorous worst-case query complexity upper bound $\mathcal{O}(s \lVert H \rVert_{\mathrm{max}}/(δ^2 \varepsilon) )$ up to logarithmic factors, where $δ$ denotes the desired precision on the coefficients appearing in the response functions. Crucially, our proposal does not suffer from the infamous state preparation bottleneck and can as such potentially achieve large quantum speedups compared to relevant classical methods. As a proof-of-principle of exponential quantum speedup, we show that a simple adaptation of our algorithm solves the random glued-trees problem in polynomial time. We discuss practical limitations as well as potential improvements for quantifying finite size, end-to-end complexities for application to relevant instances.
title Calculating response functions of coupled oscillators using quantum phase estimation
topic Quantum Physics
url https://arxiv.org/abs/2405.08694