Spontaneous symmetry breaking in scalar light front field theories

by Lubo MARTINOVIC (Bratislava)

Thursday 19 Sept 2002, 14:00 → 15:00 Europe/Zurich

TH Auditorium (CERN)

It has been a long-standing problem how one could describe spontaneous symmetry breaking (SSB) in light front (LF) field theory with its apparently 'trivial' vacuum structure. We propose a solution to this problem by formulating a quantum treatment of the SSB phenomenon in lambda phi⁴ models. It is based on quantization in a finite volume with antiperiodic real or complex scalar fields. This choice of boundary conditions avoids a necessity to solve zero mode constraints and simultaneously enables one to define a unitary operator which shifts the scalar field to the true minimum of the LF energy. Degenerate vacua, connected by parity or rotation operators, have a form of boson coherent states. The Goldstone theorem as well as some properties of the Goldstone boson state and of its matrix elements are then derived in Fock representation.