NUMERICAL SIGNATURES OF VACUUM INSTABILITY IN A ONE-DIMENSIONAL WICK-CUTKOSKY MODEL ON THE LIGHT-CONE

We extend a previous numerical study of a one-dimensional generalized Wick-Cutkosky model in which complex scalars interact via the exchange of real scalars. The numerical techniques are based on discretized li ght-cone quantization and the Lanczos diagonalization algorithm. Contr ary to previous results, we find that the vacuum instability of a cubi c theory can be detected numerically, given adequate resolution. For c omparison with the unstable case, we also consider two stable cases: o ne where a Tamm-Dancoff truncation is applied and another where a quar tic interaction of sufficient strength is added. In each case we compu te the mass gap and the critical coupling where the gap disappears.