Acceleration sensing with magnetically levitated oscillators above a superconductor

Abstract

We experimentally demonstrate stable trapping of a permanent magnet sphere above a lead superconductor, in vacuum pressures of $4\times 10^{-8}$~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 $\sim 10^{-10}\text{m}/\sqrt{\text{Hz}}$ at 30.75~Hz frequency. With current experimental parameters, we find an acceleration sensitivity of $S_a^{1/2}=1.2\pm 0.2\times 10^{-10}\text{g}/\sqrt{\text{Hz}}$, for a thermal noise limited system. By considering a 300~mK environment, at a background helium pressure of $1\times 10^{-10}$~mbar, acceleration sensitivities of $S_a^{1/2}\sim 3\times 10^{-15}\text{g}/\sqrt{\text{Hz}}$ could be possible with ideal conditions and vibration isolation. To feasibly measure with such a sensitivity, feedback cooling must be implemented.

5 pages, 3 figures, The following article has been accepted by Applied Physics Letters

References in corpus (4)

• Nanotube mechanical resonators with quality factors of up to 5 million
• Cold Damping of an Optically Levitated Nanoparticle to micro-Kelvin Temperatures
• Testing collapse models with levitated nanoparticles: the detection challenge
• Optimal control for feedback cooling in cavityless levitated optomechanics