Graphs with integral spectrum
It is shown that only a fraction of \(2^{-\Omega(n)}\) of the graphs on \(n\) vertices have an integral spectrum. Although there are several explicit constructions of such graphs, no upper bound for their number has been known. Graphs of this type play an important role in quantum networks supporting the so-called perfect state transfer.
scientific article; zbMATH DE number 5376922
scientific article