Figure 2: Experimental data.

(a) Evolution of the resonance under different gain settings. Left: Coherent state probe. Right: Squeezed state probe. Spectra are corrected for detector dark noise. The grey plane represents the optical shot noise level. The spectra are arranged proportional to the electronic gain that was set for the recording. Solid black lines stem from fits to a Lorentzian distribution. (b) Phase space trajectory of the mechanical oscillator’s position, normalized to shot noise. As the bandwidth of the detector was much larger than the mechanical dissipation rate, it was possible to monitor the thermal evolution of the oscillator in real-time. |α〉 and |ξ〉 refer to the coherent- and squeezed-state probe, respectively. Thin red circles represent the standard deviation of the distribution recorded with |α〉, green circles visualize the same quantity when the mechanical mode is probed with |ξ〉. The presented signals are low-pass filtered around the resonance frequency Ω_m with a bandwidth equal to mechanical dissipation rate Γ_m. (c) The histogram shows the marginal distribution along the quadrature of the cooled mechanical mode, comparing the squeezed (green) and the coherent (red) probe. Solid lines represent fits to the data, assuming a normal distribution, such that the vertical axis is scaled to be a probability density function (PDF), with the same normalization to unity as in the phase space plots.