S. Juchem - W. Cassing - J.M. Häuser
Institut für Theoretische Physik, Universität Gießen, D-35392 Gießen, Germany
Received: 8 January 1998 / Revised version: 7 April 1998 Communicated by A. Schäfer
Using the method of correlation dynamics we investigate the properties of a field-theory for fermions and scalar bosons coupled via a Yukawa interaction. Within this approach, which consists in an expansion of full equal-time Green functions into connected equal-time Green functions and a corresponding truncation of the hierarchy of equations of motion we carry out calculations up to 4th order in the connected Green functions and evaluate the effective potential of the theory in 1+1 dimensions on a torus. Comparing the different approximations we find a strong influence of the connected 4-point functions on the properties of the system.
11.10-z Field theory - 11.10.Ef Lagrangian and Hamiltonian approach - 11.15.Tk Other nonperturbativ techniques