Figure 1. Mechanical displacement and force sensitivity.

(a) Mechanical displacement spectrum S_z close to the mechanical resonance frequency ω_m/2π. The total displacement spectral density at ω_m is the sum of the displacement noise and the displacement imprecision . (b) Corresponding force sensitivity (dark grey). The individual components are the thermal force noise (dark yellow) and the imprecision force noise (turquoise), given by equations (1) and (2), respectively. The quantum back-action noise is neglected for simplicity. For the plots most of the parameters are those of device B, but we estimate the mass assuming that the graphene flake is a single layer. Further we choose n_add=0.5, T_bath=0.015 K, and n_p=2·10⁵ in a (see text).