Characterisation of a levitated sub-mg ferromagnetic cube in a planar alternating-current magnetic Paul trap

TL;DR

This paper demonstrates room-temperature magnetic levitation of a sub-milligram ferromagnetic cube using a planar AC magnetic Paul trap, showing promising properties for quantum sensing and coupling applications.

Contribution

It is the first characterization of a ferromagnetic cube levitated in a planar AC magnetic trap at room temperature, with analysis aligned to Mathieu equations and high-quality librational modes.

Findings

Quality factors up to 2500 for librational modes

Behavior consistent with Mathieu equations

Potential for MHz librational modes in micron-sized particles

Abstract

Microscopic levitated objects are a promising platform for inertial sensing, testing gravity at small scales, optomechanics in the quantum regime, and large-mass superpositions. However, existing levitation techniques harnessing optical and electrical fields suffer from noise induced by elevated internal temperatures and charge noise, respectively. Meissner-based magnetic levitation circumvents both sources of decoherence but requires cryogenic environments. Here we characterize a sub-mg ferromagnetic cube levitated in an alternating-current planar magnetic Paul trap at room temperature. We show behavior in line with the Mathieu equations and quality factors of up to 2500 for the librational modes. Besides technological sensing applications, this technique sets out a path for MHz librational modes in the micron-sized particle limit, allowing for magnetic coupling to superconducting circuits and spin-based quantum systems.