Although dark matter accounts for 85% of the matter in our Universe, its fundamental nature remains a mystery. It is likely passing through our laboratories on Earth unnoticed, leaving faint traces that are incredibly challenging to measure. We are developing cutting-edge quantum sensors to hunt for these elusive traces.

We use mechanical oscillators to search for dark matter¹. Dark matter particles passing by would cause the mechanical oscillators to experience occasional kicks. We will precisely monitor the mechanical oscillators and hunt for such events.

If dark matter is instead wave-like in nature, it will drive oscillatory motion of the mechanical oscillators, and we will also search for this effect.

Each of our mechanical oscillators consists of a magnetically-levitated superconductor. This platform is exceptionally well suited for dark matter searches:

• Quantum readout: We precisely monitor the motion of our levitated superconductors using superconducting quantum circuits^2-4, leveraging the rapid advances in superconducting quantum computers.
• Extreme isolation: Our levitated superconductors are highly isolated from environmental noise². They are levitated within stable traps, far from other surfaces, in ultrahigh vacuum, at extremely low temperatures (~10 mK), within magnetic shielding, and decoupled from external vibrations.

In the near term we will search for dark matter via its theorized non-gravitational interactions with ordinary matter^5,6. However, our ultimate goal is much more ambitious: to hunt for dark matter through its gravitational interaction. While all current laboratory searches rely on the existence of stronger, non-gravitational interactions, gravity is the only dark matter interaction guaranteed to exist according to astrophysical and cosmological observations. Because gravity is much weaker than the other fundamental forces, a gravity-based search is exceptionally challenging-and entirely unique.

Our vision is to build a 3D meter-scale array that is densely packed with mechanical sensors^7,8. When a dark matter particle passes through the array, its gravitational pull will excite the sensors it passes close to, leaving a 1D track of excited sensors within the 3D array. For this search the individual sensors will need to be precisely monitored using quantum sensing techniques. Magnetically-levitated superconductors make the ideal platform for building this detector.

Our group recently relocated to University College Cork (UCC), Ireland. This is an ideal location for this project, which applies quantum sensing to astroparticle physics:

• UCC has world-leading expertise in precision cryogenic experiments.
• UCC has vibrant astrophysics research environment.
• Quantum physics is a strategic priority of the university.

Our laboratory is currently being fitted for precision physics experiments. It will be fully operational with our dilution refrigerator and SQUID readout systems this Spring.