Differential Privacy of Quantum and Quantum-Inspired Classical Recommendation Algorithms

Fuente: arXiv
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Main Authors: Li, Chenjian, Ying, Mingsheng, Guan, Ji
Format: Preprint
Published: 2025
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author Li, Chenjian
Ying, Mingsheng
Guan, Ji
author_facet Li, Chenjian
Ying, Mingsheng
Guan, Ji
contents We study the differential privacy (DP) of the quantum recommendation algorithm of Kerenidis--Prakash and its quantum-inspired classical counterpart. Under standard low-rank and incoherence assumptions on the preference matrix, we show that the randomness already present in the algorithms' measurement/$\ell_2$-sampling steps can act as a privacy-curating mechanism, yielding $(\varepsilon,δ)$-DP without injecting additional DP noise through the interface. Concretely, for a system with $m$ users and $n$ items and rank parameter $k$, we prove $\varepsilon=\mathcal O(\sqrt{k/n})$ and $δ= \mathcal O\big(k^2/\min^2\{m,n\}\big)$; in the typical regime $k=\mathrm{polylog}(m,n)$ this simplifies to $\varepsilon=\tilde{\mathcal O}(1/\sqrt n)$ and $δ=\tilde{\mathcal O}\big(1/\min^2\{m,n\}\big)$. Our analysis introduces a perturbation technique for truncated SVD under a single-entry update, which tracks the induced change in the low-rank reconstruction while avoiding unstable singular-vector comparisons. Finally, we validate the scaling on real-world rating datasets and compare against classical DP recommender baselines.
format Preprint
id arxiv_https___arxiv_org_abs_2502_04758
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Differential Privacy of Quantum and Quantum-Inspired Classical Recommendation Algorithms
Li, Chenjian
Ying, Mingsheng
Guan, Ji
Quantum Physics
Cryptography and Security
Emerging Technologies
Machine Learning
We study the differential privacy (DP) of the quantum recommendation algorithm of Kerenidis--Prakash and its quantum-inspired classical counterpart. Under standard low-rank and incoherence assumptions on the preference matrix, we show that the randomness already present in the algorithms' measurement/$\ell_2$-sampling steps can act as a privacy-curating mechanism, yielding $(\varepsilon,δ)$-DP without injecting additional DP noise through the interface. Concretely, for a system with $m$ users and $n$ items and rank parameter $k$, we prove $\varepsilon=\mathcal O(\sqrt{k/n})$ and $δ= \mathcal O\big(k^2/\min^2\{m,n\}\big)$; in the typical regime $k=\mathrm{polylog}(m,n)$ this simplifies to $\varepsilon=\tilde{\mathcal O}(1/\sqrt n)$ and $δ=\tilde{\mathcal O}\big(1/\min^2\{m,n\}\big)$. Our analysis introduces a perturbation technique for truncated SVD under a single-entry update, which tracks the induced change in the low-rank reconstruction while avoiding unstable singular-vector comparisons. Finally, we validate the scaling on real-world rating datasets and compare against classical DP recommender baselines.
title Differential Privacy of Quantum and Quantum-Inspired Classical Recommendation Algorithms
topic Quantum Physics
Cryptography and Security
Emerging Technologies
Machine Learning
url https://arxiv.org/abs/2502.04758