tomograms).

Several indicators of correlations between different parts of a [*classical*]{} system have been used extensively in various applications such as automated image processing. These correlators are obtained from classical tomograms. Their definitions, however, are not intrinsically classical in nature, and it is worth examining their applicability in quantum contexts. Since correlations are inherently present in entangled states of quantum systems, a natural question that arises is whether the performance of entanglement quantifiers obtained from these correlators is comparable to that of standard indicators such as $\xi_{\textsc{svne}}$.

We examine quantum systems where the spacings between energy levels change significantly with changes in the parameters, with two or more levels moving close to each other for specific values of the parameters and then moving away as these values change. We will henceforth refer to this feature as avoided energy-level crossing. Extensive studies [@AClinkPT; @ent_change; @ent_max] have established that entanglement (as measured by standard indicators such as $\xi_{\textsc{svne}}$) is generically at an extremum at an avoided crossing. Typically, the energy spectrum and the spacing between the energy levels depend on the strengths of the nonlinearity and the coupling between subsystems. With changes in the values of these parameters, the spacing between adjacent 