The Han Lab (Chemistry, joined fall 2023) develops quantum sensing tools rooted in electron and nuclear spin physics for life-science applications. Directions: (1) DNP-enhanced NMR quantum sensing using coupled electron-nuclear spin clusters — designing novel biradical and multi-spin systems achieving 700-fold ¹³C signal enhancement at 14.1 T via P1 center clusters in HPHT diamond (exchange coupling >100 MHz); aiming for in-cell NMR with sensitivity to track water dynamics in a single cell; (2) High-field pulsed EPR at 240 GHz / 8.6 T: time-resolved Gd-Gd EPR (TiGGER) for tracking inter-residue distances during protein functional cycles in solution with sub-nm resolution; rapid-scan field-domain EPR development; (3) Integration of DNP/EPR with nanodiamond-based quantum sensors: coupled electron-nuclear spin cluster design for long-range quantum sensing in biological environments, bridging conventional NMR/EPR and NV-center-based quantum sensing. Han directs the EPR/DNP component of IMSERC (Northwestern's core facility) and brought three new EPR spectrometers and a 600 MHz DNP-NMR system.
Hemmer pioneered NV-diamond spin sensing and super-resolution with spin defects, working on coherent control, photonic integration of NV sensors, and diamond-based magnetometry/imaging bridging physics and engineering. In the broader landscape of NV-centre ensemble quantum sensing (DEER, nano-NMR, T1 relaxometry) operating near pT/sqrt(Hz) sensitivity, this work is directly in the NV ensemble sensing lineage, emphasizing photonic integration and super-resolution readout.
Hetet's group couples NV-center ensemble electron spins in electrically or optically levitated micro-diamonds to the mechanical (rotational and translational) degrees of freedom of the host particle, demonstrating spin-dependent torques strong enough to deflect a cantilever, spin-cooling of levitated motion, and NMR performed on a levitating microparticle. This complements the well-established line of NV-ensemble quantum sensing experiments (DEER, NMR, T1-relaxometry) that reach pT/sqrt(Hz)-class sensitivities, extending the toolbox toward mechanical and single-atom/single-spin readout.
NON-PREFERRED (astronomy pivot, kept for review). Hewitt builds and operates low-frequency radio interferometers (HERA, MWA) to detect the redshifted 21-cm signal from the Cosmic Dawn and Epoch of Reionization; the sensors are large radio antenna arrays rather than quantum sensors, so this is a borderline astro-instrumentation inclusion.
Explores boundary between condensed-matter physics and quantum sensing using superconductor-semiconductor circuits. Directions: (1) gate-tunable superconductor-semiconductor parametric amplifier for quantum-limited readout (PRA 2023); (2) room-temperature capacitive strong coupling to mechanical motion for electromechanical sensing (Nano Letters 2025); (3) quantum criticality in Josephson junction arrays; (4) synthetic Hamiltonians in hybrid SC-semi devices probing hidden material behavior. IST Austria → Microsoft → JILA → UChicago Nov 2023.
Studies optical quantum science in solid-state systems with emphasis on photonic integration. Directions: (1) photonic integration of NV-center spin qubits in diamond nanophotonic circuits for scalable quantum sensing arrays; (2) 2D semiconductor (TMD) nanophotonic devices exploiting valley and spin-valley degrees of freedom; (3) engineering light-matter interactions for quantum information and sensing in nanoscale optical cavities. Key goal: scalable on-chip quantum sensing platforms.
Hoffman develops and applies electron-nuclear double resonance (ENDOR) spectroscopy -- a combination of EPR and NMR -- to resolve individual hyperfine-coupled nuclei at metalloenzyme active sites with atomic-scale precision, work that has revealed mechanisms of nitrogenase nitrogen fixation, radical-SAM enzyme catalysis, and copper/methane monooxygenase chemistry. The technique pushes magnetic-resonance spectroscopic resolution well past what conventional EPR can resolve, in a manner methodologically continuous with molecular spin-qubit sensing.
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.
Hogan leads the Stanford effort on MAGIS-100, a 100-meter atom-interferometric gradiometer at Fermilab designed to search for mid-band gravitational waves and ultralight dark matter using laser-cooled strontium atoms in free fall. His group also develops compact cold-atom gravimeters and gradiometers and explores large-momentum-transfer atom optics to push interferometer sensitivity toward tests of general relativity.
Hollberg works on optical atomic clocks, laser frequency stabilization, and frequency-comb metrology, including chip-scale and field-deployable clock technology with applications to relativistic geodesy and precision tests of fundamental physics.