Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:2405.20506

Do small massive superpositions necessarily significantly entangle with gravity?

Adrian Kent

Published May 30, 2024• 0 citations
arXivHTMLPDF

Abstract

Christodoulou and Rovelli (CR) [1] have argued that a Bose et al.-Marletto-Vedral (BMV) experiment that confirmed the quantum nature of gravity would give laboratory evidence for a quantum superposition of spacetime geometries created in the course of the experiment. Hanif et al. [2] have argued that mass interferometers can be used to test whether gravity acts as a quantum entity when measured. We note that not all quantum models of gravity imply that mass superpositions necessarily become significantly entangled with any degrees of freedom of the gravitational field during the experiments discussed.

DOI
10.48550/arxiv.2405.20506

Related papers

Information content of the gravitational field of a quantum superposition

Alessio Belenchia, Robert M. Wald, Flaminia Giacomini +3 more

When a massive quantum body is put into a spatial superposition, it is of interest to consider the quantum aspects of the gravitational field sourced by the body. We argue that in order to understand how the body may become entangled with other massive bodies via gravitational interactions, it must be thought of as being entangled with its own Newtonian-like gravitational field. Thus, a Newtonian-like gravitational field must be capable of carrying quantum information. Our analysis supports the view that table-top experiments testing entanglement of systems interacting via gravity do probe the quantum nature of gravity, even if no “gravitons” are emitted during the experiment.

arXiv:1905.04496•International Journal of Modern Physics D•May 15, 2019•49 citations

What gravity mediated entanglement can really tell us about quantum gravity

Eduardo Martín-Martínez, Tales Rick Perche

We revisit the Bose-Marletto-Vedral (BMV) tabletop experimental proposal---which aims to witness quantum gravity using gravity-mediated entanglement---analyzing the role of locality in the experiment. We first carry out a fully quantum modeling of the interaction of matter and gravity and then show in what way gravity-mediated entanglement in the BMV experiment could be accounted for without appealing to quantum degrees of freedom of the gravitational field. We discuss what assumptions are needed in order to interpret the current BMV experiment proposals as a proof of quantum gravity, and also identify the modifications that a BMV-like experiment could have in order to serve as proof of quantum gravity without having to assume the existence of local mediators in the gravitational field.

arXiv:2208.09489•Physical review. D/Physical review. D.•Nov 16, 2023•41 citations

Discussions About Some Assumptions on Quantum Gravity-induced Entanglement of Masses

Jin Tan

Finding quantum characteristics in gravity has interested physicists for many decades.While there has been significant progress on the theoretical side, the experimental side still needs to yield sufficient evidence to prove the quantum nature of gravity.Therefore, the Bose et al.-Marletto-Vedral (BMV) experiment is proposed to resolve this problem.This paper analyzes two variations from the experiment that introduce the following changes: 1) linear increase in distance between masses and 2) significant time length for splitting and recombining.These variables affect the wave function by influencing the phases picked up during evolution and thus produce effects on the quantum witness.Nonetheless, despite these impacts, the entanglement between masses is reduced but not destroyed.At the end of this paper, the meaning of witnessing entanglement in the BMV experiment is discussed.Although proving the non-classicality of gravity does not guarantee the quantum nature of gravity, the experiment is sufficient to rule out classical gravity in the research of the nature of gravity.

International journal of high school research•May 31, 2024•0 citations

Gravitational decoherence by the apparatus in the quantum-gravity-induced entanglement of masses

Fabian Gunnink, Anupam Mazumdar, Martine Schut +1 more

Abstract One of the outstanding questions in modern physics is how to test whether gravity is classical or quantum in a laboratory. Recently there has been a proposal to test the quantum nature of gravity by creating quantum superpositions of two nearby neutral masses, close enough that the quantum nature of gravity can entangle the two quantum systems, but still sufficiently far away that all other known Standard Model interactions remain negligible. However, preparing superposition states of a neutral mass (the light system) requires the vicinity of laboratory apparatus (the heavy system). We will suppose that such a heavy system can be modelled as another quantum system; since gravity is universal, the lighter system can get entangled with the heavier system, providing an inherent source of gravitational decoherence. In this paper, we will consider a toy model composed of two light and two heavy quantum oscillators prepared in the motional ground state, forming pairs of probe-detector systems, and study under what conditions the entanglement between two light systems evades the decoherence induced by the heavy systems. We conclude by estimating the decoherence in the proposed experiment for testing the quantum nature of gravity.

arXiv:2210.16919•Classical and Quantum Gravity•Oct 18, 2023•10 citations

Classical Gravity Cannot Mediate Entanglement by Local Means

Chiara Marletto, Vlatko Vedral

We rebut a recent paper that claims that classical gravity can entangle two massive superpositions by local means. We refute the misconceptions appearing in this paper and confirm that the quantum features are necessary in the gravitational field if it can lead to entanglement by local propagation between distant masses.

arXiv:2510.19969•Oct 22, 2025•0 citations

Tabletop Quantum Gravity: Probing Spacetime via Massive Superposition — E8 Intelligence Research

Andrew Stewart Caldin

FINDING: Quantum gravity experiments are transitioning from theoretical speculation to tabletop-scale tests probing the quantum nature of spacetime via superposition of massive systems. MATH: The core experimental framework relies on the quantum superposition of a mass \( m \) in two spatial locations separated by \( \Delta x \), generating a gravitational phase shift \( \Delta \phi = \frac{G m^2 \Delta t}{\hbar \Delta x} \) (for two masses in superposition, per Bose–Marletto–Vedral proposal). The decoherence timescale for gravitational entanglement is \( \tau \sim \frac{\hbar \Delta x}{G m^2} \). Penrose's criterion for gravitationally-induced collapse: \( E_G = \frac{G m^2}{\Delta x} \) compared to \( \hbar/\tau \). CONNECTION: The ratio \( \frac{G m^2}{\hbar c} \) (gravitational coupling) is dimensionless and tiny (~\(10^{-45}\) for protons), but the experimental geometry uses harmonic oscillator frequencies and lattice-like trap spacings — the optimal \( \Delta x \) often scale Author: Andrew Stewart Caldin, Independent Researcher, UK. Part of the E8 Intelligence Research series. Platform: e8intelligence.com

•Sep 21, 2026•0 citations
Christodoulou and Rovelli (CR) [1] have argued that a Bose et al.-Marletto-Vedral (BMV) experiment that confirmed the quantum nature of gravity would give laboratory evidence for a quantum superposition of spacetime geometries created in the course of the experiment. Hanif et al. [2] have argued that mass interferometers can be used to test whether gravity acts as a quantum entity when measured. We note that not all quantum models of gravity imply that mass superpositions necessarily become significantly entangled with any degrees of freedom of the gravitational field during the experiments discussed.
When a massive quantum body is put into a spatial superposition, it is of interest to consider the quantum aspects of the gravitational field sourced by the body. We argue that in order to understand how the body may become entangled with other massive bodies via gravitational interactions, it must be thought of as being entangled with its own Newtonian-like gravitational field. Thus, a Newtonian-like gravitational field must be capable of carrying quantum information. Our analysis supports the view that table-top experiments testing entanglement of systems interacting via gravity do probe the quantum nature of gravity, even if no “gravitons” are emitted during the experiment.
We revisit the Bose-Marletto-Vedral (BMV) tabletop experimental proposal---which aims to witness quantum gravity using gravity-mediated entanglement---analyzing the role of locality in the experiment. We first carry out a fully quantum modeling of the interaction of matter and gravity and then show in what way gravity-mediated entanglement in the BMV experiment could be accounted for without appealing to quantum degrees of freedom of the gravitational field. We discuss what assumptions are needed in order to interpret the current BMV experiment proposals as a proof of quantum gravity, and also identify the modifications that a BMV-like experiment could have in order to serve as proof of quantum gravity without having to assume the existence of local mediators in the gravitational field.
Finding quantum characteristics in gravity has interested physicists for many decades.While there has been significant progress on the theoretical side, the experimental side still needs to yield sufficient evidence to prove the quantum nature of gravity.Therefore, the Bose et al.-Marletto-Vedral (BMV) experiment is proposed to resolve this problem.This paper analyzes two variations from the experiment that introduce the following changes: 1) linear increase in distance between masses and 2) significant time length for splitting and recombining.These variables affect the wave function by influencing the phases picked up during evolution and thus produce effects on the quantum witness.Nonetheless, despite these impacts, the entanglement between masses is reduced but not destroyed.At the end of this paper, the meaning of witnessing entanglement in the BMV experiment is discussed.Although proving the non-classicality of gravity does not guarantee the quantum nature of gravity, the experiment is sufficient to rule out classical gravity in the research of the nature of gravity.
Abstract One of the outstanding questions in modern physics is how to test whether gravity is classical or quantum in a laboratory. Recently there has been a proposal to test the quantum nature of gravity by creating quantum superpositions of two nearby neutral masses, close enough that the quantum nature of gravity can entangle the two quantum systems, but still sufficiently far away that all other known Standard Model interactions remain negligible. However, preparing superposition states of a neutral mass (the light system) requires the vicinity of laboratory apparatus (the heavy system). We will suppose that such a heavy system can be modelled as another quantum system; since gravity is universal, the lighter system can get entangled with the heavier system, providing an inherent source of gravitational decoherence. In this paper, we will consider a toy model composed of two light and two heavy quantum oscillators prepared in the motional ground state, forming pairs of probe-detector systems, and study under what conditions the entanglement between two light systems evades the decoherence induced by the heavy systems. We conclude by estimating the decoherence in the proposed experiment for testing the quantum nature of gravity.
FINDING: Quantum gravity experiments are transitioning from theoretical speculation to tabletop-scale tests probing the quantum nature of spacetime via superposition of massive systems. MATH: The core experimental framework relies on the quantum superposition of a mass m m m in two spatial locations separated by Δx \Delta x Δx, generating a gravitational phase shift Δϕ=Gm2ΔtℏΔx \Delta \phi = \frac{G m^2 \Delta t}{\hbar \Delta x} Δϕ=ℏΔxGm2Δt​ (for two masses in superposition, per Bose–Marletto–Vedral proposal). The decoherence timescale for gravitational entanglement is τ∼ℏΔxGm2 \tau \sim \frac{\hbar \Delta x}{G m^2} τ∼Gm2ℏΔx​. Penrose's criterion for gravitationally-induced collapse: EG=Gm2Δx E_G = \frac{G m^2}{\Delta x} EG​=ΔxGm2​ compared to ℏ/τ \hbar/\tau ℏ/τ. CONNECTION: The ratio Gm2ℏc \frac{G m^2}{\hbar c} ℏcGm2​ (gravitational coupling) is dimensionless and tiny (~10−4510^{-45}10−45 for protons), but the experimental geometry uses harmonic oscillator frequencies and lattice-like trap spacings — the optimal Δx \Delta x Δx often scale Author: Andrew Stewart Caldin, Independent Researcher, UK. Part of the E8 Intelligence Research series. Platform: e8intelligence.com