Cushing's group develops quantum-light (entangled-photon) spectroscopies and tabletop attosecond/X-ray methods to probe electron and energy dynamics with quantum-enhanced sensitivity and resolution, including entangled-photon spectroscopy and imaging beyond classical shot-noise limits. For context, this complements the established paradigm of NV-diamond ensemble magnetometry (Hahn-echo/DEER, nanoscale NMR, T1 relaxometry) operating near pT/√Hz sensitivity.