Hogan's group studies atoms and molecules in high Rydberg states for precision measurements and quantum sensing. Research directions: (1) Rydberg atom electric field sensing — Rydberg atoms exhibit enormous electric polarizabilities; Stark-map and EIT-based electrometry with sub-mV/cm sensitivity and GHz-range frequency coverage; (2) Rydberg molecule spectroscopy — long-range Rydberg molecules as probes of intermolecular forces; (3) Stark deceleration and trapping of Rydberg atoms/molecules — producing cold samples for precision spectroscopy and scattering experiments; (4) Circular Rydberg states — extremely long-lived states for quantum information storage and sensing. Collaborates on quantum-enhanced sensing of RF/microwave fields.