Causality as an emergent macroscopic phenomenon: The Lee-Wick O(N) model

Understand

In quantum mechanics the deterministic property of classical physics is an emergent phenomenon appropriate only on macroscopic scales.

• Lee and Wick introduced Lorentz invariant quantum theories where causality is an emergent phenomenon appropriate for macroscopic time scales.
• In this paper we analyze a Lee-Wick version of the O(N) model.
• We argue that in the large N limit this theory has a unitary and Lorentz invariant S matrix and is therefore free of paradoxes in scattering experiments.