Abstract
Let G be a graph with adjacency matrix A. The transition matrix of G is denoted by H(t) and it is defined by The graph G has perfect state transfer (PST) from a vertex u to another vertex v if there exist
such that the uvth entry of
has unit modulus. In case when
, we say that G is periodic at the vertex u at time
. The graph G is said to be periodic if it is periodic at all vertices at the same time. A gcd-graph is a Cayley graph over a finite abelian group defined by greatest common divisors. We establish a sufficient condition for a gcd-graph to have periodicity and PST at
. Using this we deduce that there exists gcd-graph having PST over an abelian group of order divisible by 4. Also we find a necessary and sufficient condition for a class of gcd-graphs to be periodic at
. Using this we characterize a class of gcd-graphs not exhibiting PST at
for all positive integers k.
Acknowledgements
We thank the anonymous reviewer(s) for the useful comments in an earlier manuscript.
Notes
No potential conflict of interest was reported by the authors.