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Event

Xiaohong Zhang (Université de Montréal)

Tuesday, January 24, 2023 15:30to16:30

Title: Oriented Cayley graphs with nice eigenvalues

´¡²ú²õ³Ù°ù²¹³¦³Ù:ÌýLet $G$ be a finite abelian group. Bridges and Mena characterized the Cayley graphs on $G$ that have only integer eigenvalues. An oriented Cayley graph on $G$ is a Cayley digraph $X(G,C)$ such that $C$ and $(-C)$ are disjoint. Consider the $(0,1,-1)$ skew-symmetric adjacency matrix of an oriented Cayley graph. We give a characterization of when all its eigenvalues are integer multiples of $sqrt{Delta}$ for some square-free integer $Delta<0$. This also characterizes oriented Cayley graphs on which continuous quantum walks are periodic, a necessary condition for the walk to admit uniform mixing or perfect state transfer. 

Seminar Physique Mathématique
CRM-Salle 4336-4384, Pav. André Aisenstadt

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