Micron-size spatial superpositions for the QGEM-protocol via screening and trapping

Abstract

The quantum gravity-induced entanglement of masses (QGEM) protocol for testing quantum gravity using entanglement witnessing utilizes the creation of spatial quantum superpositions of two neutral, massive matter-wave interferometers kept adjacent to each other, separated by a distance d. The mass and the spatial superposition should be such that the two quantum systems can entangle solely via the quantum nature of gravity. Despite being charge-neutral, there are many electromagnetic backgrounds that can also entangle the systems, such as the dipole-dipole interaction, and the Casimir-Polder interaction. To minimize electromagnetic-induced interactions between the masses it is pertinent to isolate the two superpositions by a conducting plate. However, the conducting plate will also exert forces on the masses and hence the trajectories of the two superpositions would be affected. To minimize this effect, we propose to trap the two interferometers such that the trapping potential dominates over the attraction between the conducting plate and the matter-wave interferometers. The superpositions can still be created via the Stern-Gerlach effect in the direction parallel to the plate, where the trapping potential is negligible. The combination of trapping and shielding provides a better parameter space for the parallel configuration of the experiment, where the requirement on the size of the spatial superposition, to witness the entanglement between the two masses purely due to their quantum nature of gravity, decreases by at least two orders of magnitude as compared to the original protocol paper.

Version accepted to PRR

References in corpus (10)

• A Spin Entanglement Witness for Quantum Gravity
• Gravitationally-induced entanglement between two massive particles is sufficient evidence of quantum effects in gravity
• Motional Quantum Ground State of a Levitated Nanoparticle from Room Temperature
• Quantum Decoherence
• Effective EMI shielding behaviour of thin graphene/PMMA nanolaminates in the THz range
• Decoherence effects in non-classicality tests of gravity
• Witnessing the non-classical nature of gravity in the presence of unknown interactions
• Long Spin Coherence Times of Nitrogen Vacancy Centres in Milled Nanodiamonds
• Relaxation of experimental parameters in a Quantum-Gravity Induced Entanglement of Masses Protocol using electromagnetic screening
• Electromagnetic properties of polycrystalline diamond from 35K to room temperature and microwave to terahertz frequencies

Cited by in corpus (10)

• Decoherence of a matter-wave interferometer due to dipole-dipole interactions
• Dephasing due to electromagnetic interactions in spatial qubits
• Testing Whether Gravity Acts as a Quantum Entity When Measured
• Quantum signature of gravity in optomechanical systems with conditional measurement
• Phonon-induced contrast in a matter-wave interferometer
• Inertial Torsion Noise in Matter-Wave Interferometers for Gravity Experiments
• Magnetic noise in macroscopic quantum spatial superposition
• Theoretical Study of the Squeezed-Light-Enhanced Sensitivity to Gravity-Induced Entanglement via Finite-Time Analysis
• Gravity induced entanglement of multiple massive particles with large spin
• Entanglement witnesses mediated via axionLike particles