  We investigate the quantum networks that their nodes are considered as
quantum harmonic oscillators. The entanglement of the ground state can be used
to quantify the amount of information one part of a network shares with the
other part of the system. The networks which we studied in this paper, are
called strongly regular graphs (SRG). These kinds of graphs have some special
properties like they have three strata in the stratification basis. The Schur
complement method is used to calculate the Schmidt number and entanglement
entropy between two parts of graph. We could obtain analytically, all blocks of
adjacency matrix in several important kinds of strongly regular graphs. Also
the entanglement entropy in the large coupling limit is considered in these
graphs and the relationship between Entanglement entropy and the ratio of size
of boundary to size of the system is found. Then, area-law is studied to show
that there are no entanglement entropy for the highest size of system. Then,
the graph isomorphism problem is considered in SRGs by using the elements of
blocks of adjacency matrices. Two SRGs with the same parameters:
$(\eta,\kappa,\lambda,\nu)$ are isomorphic if they can be made identical by
relabeling their vertices. So the adjacency matrices of two isomorphic SRGs
become identical by replacing of rows and columns. The nonisomirph SRGs could
be distinguished by using the elements of blocks of adja- cency matrices in the
stratification basis, numerically.
