Perfect state transfer in integral circulant graphs

The existence of perfect state transfer in quantum spin networks based on integral circulant graphs has been considered recently by Saxena, Severini and Shparlinski. We give the simple condition for characterizing integral circulant graphs allowing the perfect state transfer in terms of its eigenvalues. Using that, we complete the proof of results stated by Saxena, Severini and Shparlinski. Moreover, it is shown that in the class of unitary Cayley graphs there are only two of them allowing perfect state transfer.