  Jahn-Teller effect (JTE) widely exists in polyatomic systems including
organic molecules, nano-magnets, and solid-state defects. Detecting the JTE at
single-molecule level can provide unique properties about the detected
individual object. However, such measurements are challenging because of the
weak signals associated with a single quantum object. Here, we propose that the
dynamic JTE of single defects in solids can be observed with nearby quantum
sensors. With numerical simulations, we demonstrate the real-time monitoring of
quantum jumps between different stable configurations of single substitutional
nitrogen defect centers (P1 centers) in diamond. This is achieved by measuring
the spin coherence of a single nitrogen-vacancy (NV) center near the P1 center
with the double electron-electron resonance (DEER) technique. Our work extends
the ability of NV center as a quantum probe to sense the rich physics in
various electron-vibrational coupled systems.
