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arXiv · 2601.06608

Magnetic levitation and spatial superposition of a nanodiamond with a current-carrying chip

Qian Xiang·Shafaq Gulzar Elahi·Andrew Geraci·Sougato Bose·Anupam Mazumdar
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Abstract

We propose a current-carrying-chip scheme for generating spatial quantum superpositions using a levitating nanodiamond with a built-in nitrogen-vacancy (NV) centre defect. Our setup is quite versatile and we aim to create the superposition for a mass range of $10^{-19}~{\rm kg}< m< 10^{-15}~{\rm kg}$ and a superposition size ${\cal O}(10) {\rm \mu m} < \Delta x < {\cal O}(1){\rm nm}$, respectively, in $t\leq 0.1$s, depending on the position we launch from the center of the diamagnetic trap. We provide an in-depth analysis of two parallel chips that can create levitation and spatial superposition along the $x$-axis, while producing a very tight trap in the $y$ direction, and the direction of gravity, i.e., the $z$ direction. Numerical simulations demonstrate that our setup can create a one-dimensional spatial superposition state along the x-axis. Throughout this process, the particle is stably levitated in the z-direction, and its motion is effectively confined in the y-direction for a Gaussian initial condition. This setup presents a viable platform for a diamagnetically levitated nanoparticle for a table-top experiment exploring the possibility of creating a macroscopic Schr\"odinger Cat state to test the quantum gravity induced entanglement of masses (QGEM) protocol.

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Qian Xiang, Shafaq Gulzar Elahi, Andrew Geraci, Sougato Bose, Anupam Mazumdar. 2026-01-10. Magnetic levitation and spatial superposition of a nanodiamond with a current-carrying chip. https://arxiv.org/abs/2601.06608

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