Jean-Marie Barbaroux, Francois Germinet, Serguei Tcheremchantsev Fractal dimensions and the Phenomenon of Intermittency in Quantum Dynamics (657K, .ps) ABSTRACT. We exhibit an intermittency phenomenon in quantum dynamics. More precisely we derive new lower bounds for the moments of order {\it p} associated to the state $\psi(t)={\rm e}^{-itH}\psi$ and averaged in time between $0$ and {\it T}. These lower bounds are expressed in terms of generalized fractal dimensions $D^\pm_{\mu_\psi}(1/(1+p/d))$ of the measure $\mu_\psi$ (where {\it d} is the space dimension). This improves notably previous results, obtained in terms of Hausdorff and Packing dimension.