Seidel switching for weighted multi-digraphs and its quantum perspective

Understand

Construction of graphs with equal eigenvalues (co-spectral graphs) is an interesting problem in spectral graph theory.

• Seidel switching is a well-known method for generating co-spectral graphs.
• From a matrix theoretic point of view, Seidel switching is a combined action of a number of unitary operations on graphs.
• Recent works [1] and [2] have shown significant connections between graph and quantum information theories.