  We propose an optomechanical nano-gravimeter based on exceptional points. The
system is a coupled cavity optomechanical system, in which the gain and loss
are applied by driving the cavities with a blue detuned and red detuned
electromagnetic field, respectively. When the gain and loss reach a balance,
the system will show the degeneracy of exceptional points, and any perturbation
will cause an eigenfrequencies split, which is proportional to the square root
of the perturbation strength. Compared with the traditional optomechanical
sensors, the sensitivity is greatly enhanced. This work paves the way for the
design of optomechanical ultrasensitive force sensors that can be applied to
detect non-Newtonian effects, high-order weak interactions, and so on.
