The spectrum of a quantum system has in general bound, scattering and
resonant parts. The Hilbert space includes only the bound and scattering
spectra, and discards the resonances. One must therefore enlarge the Hilbert
space to a rigged Hilbert space, within which the physical bound, scattering
and resonance spectra are included on the same footing. In these lectures, I
will explain how this is done.Comment: 23 pages; written version of the five-lecture course delivered at the
2006 Summer School of CINVESTAV, Mexico City, July 200
