Summary of working group 3: New challenges in theory and modeling

Working group three was devoted to contributions on theory and modeling of devices and new ideas, aiming at increasing the beam brightness and at generating radiation at short wavelengths. The contributions presented span from the beam dynamics in radiofrequency accelerators, emittance compensation schemes and optimization of the beam brightness at low energy, analysis of the emittance dilution processes during acceleration and compression, laser plasma sources and the generation of radiation in FELs and other radiation sources. Analysis specifically oriented to the modeling of the beam and radiation dynamics were also presented.