On the periods of motives with complex multiplication and a conjecture of Gross-Deligne

 
V. Maillot and D. Roessler

 
 
  We prove that the existence of an automorphism of finite order on a variety X defined over a number field implies the existence of algebraic linear relations between the logarithm of certain periods of X and the logarithm of special values of the Gamma-function. This implies that a slight variation of results by Anderson, Colmez and Gross on the periods of CM abelian varieties is valid for a larger class of CM motives. In particular, we prove a weak form of the period conjecture of Gross-Deligne.

Our proof relies on the arithmetic fixed point formula (equivariant arithmetic Riemann-Roch theorem) proved by K. Köhler and the second author, and the vanishing of the equivariant analytic torsion for the Dolbeault complex.