Figure 1
(a) QFI vs. \(\lambda t\), (b) Fidelity vs. \(\lambda t\), for \(N=34\) and \(n_m=903\) (red), \(N=28\) and \(n_m=613\) (green), \(N=25\) and \(n_m=488\) (brown), \(N=10\) and \(n_m=78\) (pink), \(N=5\) and \(n_m=20\) (sky blue). Here \(D/\lambda \) \(=0.01\) and the maximal time is \(\lambda t_m\) \(=4\). Here we do not consider the d–d interaction and the collective decay of the atoms, i.e., \(g=\) \(\gamma =0\), and the difference interval of the estimated phase is \(\delta \phi \) \(=0.0001\). In (a,b), blue lines indicate the curve got from the analytical expression, and the red, green, brown, pink, sky blue lines indicate the numerical simulation result got from this paper under the same parameters, respectively.
