be employed. In , we investigate how these indicators behave close to avoided crossings in the two bipartite CV models mentioned above. In , we extend our analysis to the multipartite HQ model. Concluding remarks are made in .

\[sec:review\]Entanglement indicators from tomograms
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We first consider generic CV systems. A typical example of a bipartite CV system is two coupled oscillators (equivalently, a single-mode radiation field interacting with a multilevel atom modelled as an oscillator). The tomogram is obtained from the quorum of observables that contain complete information about the state. These observables are represented by the rotated quadrature operators $$\mathbb{X}_{{\theta_{\textsc{a}}}} = (a \,e^{-i {\theta_{\textsc{a}}}} + a^{\dagger} \,e^{i {\theta_{\textsc{a}}}})/\sqrt{2},\;\;
 \mathbb{X}_{{\theta_{\textsc{b}}}} = (b e^{-i {\theta_{\textsc{b}}}} + b^{\dagger} e^{i {\theta_{\textsc{b}}}})/\sqrt{2}.
\label{eqn:rotQuadOps}$$ Here $0 \leqslant  {\theta_{\textsc{a}}}, {\theta_{\textsc{b}}}< \pi$, and $(a, a^{\dagger})$ \[respectively, $(b, b^{\dagger})$\] are the oscillator annihilation and creation operators corresponding to the two subsystems A and B. The bipartite tomogram is given by $$w(X_{{\theta_{\textsc{a}}}},{\theta_{\textsc{a}}};  X_{{\theta_{\textsc{b}}}},{\theta_{\textsc{b}}}) =
\bra{X_{{\theta_{\textsc{a}}}},{\theta_{\textsc{a}}};X_{{\theta_{\textsc{b}}}},{\theta_{\textsc{b}}}} \rho_{\textsc{ab}} \ket{X_{{\theta_{\textsc{a}}}},{\theta_{\textsc{a}}};X_{{\theta_{\textsc{b}}}},{\theta_{\textsc{b}}}}, 
\label{eqn:tomoDefn}$$ where $\rho_{\textsc{ab}}$ denotes the bipartite density matrix. Here $\mathbb{X}_{\theta_{i}}\ket{X_{\theta_{i}},\theta_{i}}=X_{\theta_{i}}\ket{X_{\theta_{i}},\theta_{i}}$ ($i$=A,B), and the product basis state $\ket{X_{{\theta_{\textsc{a}}}},{\theta_{\textsc{a}}}} \otimes \ket{X_{{\theta_{\textsc{b}}}},{\theta_{\textsc{b}}}}$ is written as $\ket{X_{{\theta_{\textsc{a}}}},{\theta_{\textsc{a}}};X_{{\theta_{\textsc{b}}}},{\theta_{\textsc{b}}}}$. The normalization condition is given by $$\int_{-\infty}^{\infty}\! \rmd X_{{\theta_{\textsc{a}}}} \int_{-\infty}^{\infty} \!\rmd X_{{\theta_{\textsc{b}}}} w(X_{{\theta_{\textsc{a}}}},{\theta_{\textsc{a}}};X_{{\theta_{\textsc{b}}}},{\theta_{\textsc{b}}}) = 1
\label{eqn:tomoNorm}$$ for each 