We experimentally demonstrate the stable trapping of a permanent magnet sphere above a lead superconductor, at vacuum pressures of mbar. The levitating magnet behaves as a harmonic oscillator, with frequencies in the 4–31 Hz range detected, and shows promise to be an ultrasensitive acceleration sensor. We directly apply an acceleration to the magnet with a current carrying wire, which we use to measure a background noise of at 30.75 Hz frequency. With current experimental parameters, we find an acceleration sensitivity of , for a thermal noise limited system. By considering a 300 mK environment, at a background helium pressure of mbar, acceleration sensitivities of could be possible with ideal conditions and vibration isolation. To feasibly measure with such a sensitivity, feedback cooling must be implemented.
The Earth's magnetic field in Southampton, UK (at sea level) has a vertical component of 44 469.57 nT and a horizontal component of 19 813.59 nT.