Regal's group laser-cools membrane mechanical oscillators to measure displacement and tiny forces at quantum limits, assembles and entangles single neutral atoms in optical tweezers, and develops optical-to-microwave transduction and atom-based magnetometry - exploring control at the atomic, optical, and mesoscopic quantum frontier. For context, this complements the established paradigm of NV-diamond ensemble magnetometry (Hahn-echo/DEER, nanoscale NMR, T1 relaxometry) operating near pT/√Hz sensitivity.