Benign versus malicious ghosts in higher-derivative theories
Jul, 2004Citations per year
Abstract:
Interacting theories with higher derivatives involve ghosts. They correspond to instabilities that display themselves at the classical level. We notice that comparatively benign mechanical higher-derivative systems exist where the classical vacuum is stable with respect to small perturbations and the problems appear only at the nonperturbative level. We argue that benign higher-derivative field theories exist which are stable with respect to small fluctuations with nonzero momenta. A particular example is the 6D N=2 higher-derivative SYM theory, which is finite and unitary at the perturbative level. The inflation-like instability with respect to small fluctuations of static modes is always present, however.Note:
- 22 pages LaTeX, 4 ps figures. Final version published in Nucl. Phys. B
- 11.15.-q
- 11.15.Bt
- 11.10.Kk
- field theory: action
- derivative: high
- ghost
- effective action
- gauge field theory: Yang-Mills
- field theory: scalar
- perturbation theory: higher-order
References(13)
Figures(4)