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.

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.