Macroscopic quantum coherence and entanglement in mechanical systems

Fuente: arXiv
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Autores principales: Yadin, Benjamin, Fadel, Matteo
Formato: Preprint
Publicado: 2025
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author Yadin, Benjamin
Fadel, Matteo
author_facet Yadin, Benjamin
Fadel, Matteo
contents The notion of a macroscopic quantum state must be pinned down in order to assess how well experiments probe the large-scale limits of quantum mechanics. However, the issue of quantifying so-called quantum macroscopicity is fraught with multiple approaches having varying interpretations and levels of computability and measurability. Here, we introduce two measures that capture independent macroscopic properties: i) extensive size, measuring the degree of coherence in position or momentum observables relative to atomic-scale units, and ii) entangled size, quantifying the number of entangled subsystems. These measures unify many desirable features of past proposals while having rigorously justified interpretations from quantum information theory in terms of coherence and multipartite entanglement. We demonstrate how to estimate them and obtain lower-bounds using experimental data from micro-mechanical oscillators and diffracting molecules. Notably, we find evidence for genuine multipartite entanglement of $10^6$ to $10^7$ atoms in recent mechanical superposition states.
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id arxiv_https___arxiv_org_abs_2503_08324
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Macroscopic quantum coherence and entanglement in mechanical systems
Yadin, Benjamin
Fadel, Matteo
Quantum Physics
The notion of a macroscopic quantum state must be pinned down in order to assess how well experiments probe the large-scale limits of quantum mechanics. However, the issue of quantifying so-called quantum macroscopicity is fraught with multiple approaches having varying interpretations and levels of computability and measurability. Here, we introduce two measures that capture independent macroscopic properties: i) extensive size, measuring the degree of coherence in position or momentum observables relative to atomic-scale units, and ii) entangled size, quantifying the number of entangled subsystems. These measures unify many desirable features of past proposals while having rigorously justified interpretations from quantum information theory in terms of coherence and multipartite entanglement. We demonstrate how to estimate them and obtain lower-bounds using experimental data from micro-mechanical oscillators and diffracting molecules. Notably, we find evidence for genuine multipartite entanglement of $10^6$ to $10^7$ atoms in recent mechanical superposition states.
title Macroscopic quantum coherence and entanglement in mechanical systems
topic Quantum Physics
url https://arxiv.org/abs/2503.08324