Variational methods in nuclear pairing theory

Particle number conserving groundstate wave functions are constructed by use of the Thouless-Peierls formalism. A comparison with PBCS- and FBCS-solutions shows an encouraging advantage of this method: 1. the groundstate is lower in energy than the FBCS groundstate, 2. the computer time necessary to obtain the groundstate wave function as well as its energy is smaller than with the FBCS method.