# Ultrasensitive Inertial and Force Sensors with Diamagnetically Levitated Magnets

## TL;DR

This paper proposes a theoretically designed ultrasensitive force and inertial sensor using a diamagnetically levitated magnet above a superconductor, achieving extremely high sensitivity for various scientific and technological applications.

## Contribution

It introduces a novel stable levitation method for magnets without external fields and demonstrates its potential as an ultra-sensitive sensor with unprecedented sensitivity levels.

## Key findings

- Force sensitivity around 10^{-23} N/√Hz for 100 nm magnets
- Acceleration sensitivity around 10^{-14} g/√Hz for 10 mm magnets
- Potential applications in gravimetry, space industry, and fundamental physics

## Abstract

We theoretically show that a magnet can be stably levitated on top of a punctured superconductor sheet in the Meissner state without applying any external field. The trapping potential created by such induced-only superconducting currents is characterized for magnetic spheres ranging from tens of nanometers to tens of millimeters. Such a diamagnetically levitated magnet is predicted to be extremely well isolated from the environment. We therefore propose to use it as an ultrasensitive force and inertial sensor. A magnetomechanical read-out of its displacement can be performed by using superconducting quantum interference devices. An analysis using current technology shows that force and acceleration sensitivities on the order of $10^{-23}\text{N}/\sqrt{\text{Hz}}$ (for a 100 nm magnet) and $10^{-14}g/\sqrt{\text{Hz}}$ (for a 10 mm magnet) might be within reach in a cryogenic environment. Such unprecedented sensitivities can be used for a variety of purposes, from designing ultra-sensitive inertial sensors for technological applications (i.e. gravimetry, avionics, and space industry), to scientific investigations on measuring Casimir forces of magnetic origin and gravitational physics.