Figure 4

The time evolution of final mean phonon number \(n_{f}^{i}\) (\(i=1,2\)) and quantum synchronization \(S_{c}\) without the voltage modulation (\(\eta =0\)). The pink shaded region signifies the ground state cooling for \(N<1\). Here we set \(\omega _{\mathrm{lc}}=\omega _{0}\) in (a), and \(\omega _{\mathrm{lc}}/\omega _{0}=10\) in (b). The other parameters are the same as in Fig. 3