Gain-free quantum sensing via \mathcalPT-like-induced coherence enhancement in cavity-magnomechanical system

A gain-free \mathcalPT-like-induced coherence enhancement quantum sensing scheme is implemented in a cavity-magnomechanical system. In the absence of a conventional gain-loss balance, \mathcalPT-like behavior arises near an exceptional point, where symmetry and its breaking lead to robust quantum coherence. The optimal sensing regime is directly determined by the phase of the coherent parameters. Governed alternately by the \mathcalPT-symmetric and symmetry-broken regimes, this quantum coherence can either suppress or enhance the signal-to-noise ratio, depending on the probe configuration. These results provide a clear and experimentally friendly framework for optimizing quantum-coherence-based sensing in realistic hybrid quantum systems.