Develops quantum metrology for ultra-weakly-coupled dark sectors and fundamental physics. Directions: (1) axion dark matter detection using entangled probe state preparation and superconducting qubit QND readout (HAYSTAC, ADMX); (2) dark radiation/energy detection with Cooper-pair box quasiparticle sensors; (3) GW detectors based on high-B-field microwave cavities probing early-universe phase transitions; (4) emergent gauge symmetries in quantum spin liquids. Co-PI DARPA QuSeN (quantum sensing of neutrinos, 2025). Devices/Sensors lead, DOE Quantum Science Center.

Prof. Figueroa-Feliciano leads Northwestern's experimental program in quantum sensing for particle physics. Key directions: (1) SuperCDMS SNOLAB — Northwestern's NU's role in the Super Cryogenic Dark Matter Search at SNOLAB (2 km underground in Canada), using ultra-pure Si and Ge crystals with superconducting TES sensors to detect low-mass dark matter (particles below the proton mass); in March 2026 the experiment reached operating temperature (<10 mK), transitioning to detector calibration for the first ever dark matter search at the site; (2) NEXUS facility at Fermilab: Northwestern-built test facility led by Figueroa-Feliciano for SuperCDMS detector calibration and for measuring how ionizing radiation affects superconducting qubits (published fall 2025); (3) Qubit-based quantum sensing: developing HVeV R&D devices with <1 eV resolution and qubit parity-detection techniques for eV-scale and sub-eV dark matter detection. Associate Vice President for Research at Northwestern; INQUIRE Executive Committee. Joint appointment at Fermilab.

Grassellino directs the DOE's SQMS Center, a Fermilab-Northwestern-led national quantum initiative center, and pioneered nitrogen-doping surface treatments that give niobium superconducting RF (SRF) cavities record-high quality factors. Beyond their traditional use in particle accelerators, these ultra-high-Q cavities are now deployed as extremely sensitive electromagnetic detectors: the Dark SRF experiment set new sensitivity limits on dark-photon light-shining-through-wall searches, and SRF cavities (e.g. the MAGO design) are being explored as high-frequency gravitational-wave and axion detectors, alongside long-lived multimode quantum memories for superconducting quantum computing.

Hogan proposed that the holographic principle implies a fundamental, universal quantum uncertainty ('holographic noise') in the transverse position of spacetime at the Planck scale, and co-led the Fermilab Holometer -- twin co-located, power-recycled Michelson interferometers -- to search for it, ruling out the simplest models to high significance. This is a distinct fundamental-light-physics/quantum-sensing approach from squeezed-light-enhanced GW interferometers (e.g., LIGO), using precision laser interferometry to probe quantum properties of spacetime itself rather than squeezing quantum noise in a detector.

Romanenko leads the Quantum Technology thrust at the SQMS Center, using ultra-high-coherence 3D niobium SRF cavities as both long-lived quantum memories for multimode superconducting quantum computing and as ultra-sensitive detectors for fundamental physics. He conceived and led the Dark SRF experiment, the first demonstration of SRF cavities used as light-shining-through-wall detectors, achieving new sensitivity limits for hidden-sector dark photons, and continues to explore SRF-based sensing of dark matter and gravitational waves.