Quantum phase transition of infrared radiation

Abstract

Abstract We describe a phase transition of infrared radiation, driven by quantum fluctuations, which takes place at the boundary of (the conformal diagram of) Minkowski spacetime. Specifically, we consider a family of states interpolating between the vacuum and the Kraus-Polley-Reents infravacuum. A state from this family can be imagined as a static source emitting flashes of infrared radiation in distant past. The flashes are in suitable squeezed states and the time intervals between them are controlled by a certain parameter r. For r 0 lightcone normality breaks down, the S-matrix is stabilized by the Kraus-Polley-Reents mechanism and the rotational symmetry is restored. We interpret these two situations as ordered (r 0) phase of infrared radiation, and show that they can be distinguished by asymptotic fluctuations of the fields. We also determine the singular behaviour of some S-matrix elements near the critical point r = 0.

Keywords

• Nonperturbative Effects
• Global Symmetries
• Space-Time Symmetries