Probing quantum mechanics and quantum aspects of general relativity, along with the sensing and constraining of classical gravity, can all be enabled by unprecedented spatial sizes of superpositions of massive objects. In this paper, we show that there is a feasible setup sourced by realizable magnetic field gradients $O\left(10\text{–}100\right)\mathrm{T}$ ${\mathrm{m}}^{-1}$ to construct a large spatial superposition of $O\left({10}^{-4}\text{–}{10}^{-8}\right)\mathrm{m}$ for $O\left({10}^{-17}\text{–}{10}^{-14}\right)\mathrm{kg}$ masses within a time of up to 0.1–10 seconds. The scale of superpositions is unrestricted as long as quantum coherence can be maintained for a required amount of time.

• Received 27 June 2021
• Accepted 21 January 2022

DOI:https://doi.org/10.1103/PhysRevResearch.4.023087

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

Published by the American Physical Society