  We study damping signatures at the Jiangmen Underground Neutrino Observatory
(JUNO), a medium-baseline reactor neutrino oscillation experiment. These
damping signatures are motivated by various new physics models, including
quantum decoherence, $\nu_3$ decay, neutrino absorption, and wave packet
decoherence. The phenomenological effects of these models can be characterized
by exponential damping factors at the probability level. We assess how well
JUNO can constrain these damping parameters and how to disentangle these
different damping signatures at JUNO. Compared to current experimental limits,
JUNO can significantly improve the limits on $\tau_3/m_3$ in the $\nu_3$ decay
model, the width of the neutrino wave packet $\sigma_x$, and the intrinsic
relative dispersion of neutrino momentum $\sigma_{\rm rel}$.
