Facultat de Matemàtiques, Universitat de València, Burjassot, València 46100, Spain ; Department of Mathematics, University of Florida, Gainesville, Florida 32611
Abstract:
We prove that a finite group has two rational-valued irreducible characters if and only if it has two rational conjugacy classes, and determine the structure of any such group. Along the way we also prove a conjecture of Gow stating that any finite group of even order has a non-trivial rational-valued irreducible character of odd degree.