Speaker
Description
Quantum sensing has matured rapidly into a competitive platform for fundamental physics, and arrays of mechanical sensors are now positioned to test well-motivated dark matter scenarios long considered out of experimental reach. I will discuss POLONAISE, a magnetic-levitation experiment at Leiden University that re-purposes cryogenic vibration-isolation hardware originally developed for the Einstein Telescope Pathfinder as a direct dark matter detector. Using this platform, we have performed the first laboratory search for ultralight vector dark matter coupled to B–L with a magnetically levitated mass [Amaral et al., PRL 134, 251001 (2025)], setting a constraint of g_{B−L} ≲ 3 × 10⁻²¹ near 10⁻¹³ eV/c² and laying out a staged upgrade path projected to surpass MICROSCOPE and LIGO/Virgo. I will then present new results from our December 2025 data run searching for ultraheavy dark matter at 10⁷–10¹¹ GeV coupling to ordinary matter via a long-range force, in a regime not covered by existing direct-detection experiments. I will close with a discussion of other measurements we are pursuing with this technology and my outlook for this emerging interdisciplinary program.