Gravitons probing from stochastic gravitational waves background
  Quantum gravity is a challenge in physics, and the existence of graviton is
the prime question at present. We study the detectability of the quantum noise
induced by gravitons in this letter. The correlation of the quantum noise in
the squeezed state is calculated, but we are surprised to find that the result
is the same as those from Grishchuk et.al. and Parikh et.al. This implies that
they are essentially about one thing: the quantum noise from the gravitons. The
further discussion shows the quantum noise should be completed from the leading
order of the interaction between gravitation and the detector. The squeezed
factor is estimated, and with it, the spectrum of the quantum noise is found to
be of the form $\Omega_0 \sim \nu^{4+a_0 \beta+b_0}$. After comparing it to the
sensitivities of several gravitational wave detectors, we conclude that the
quantum noise is detectable in the future.
