Fig. 2: Projected RG flows in (X, Y)-plane.
From: Multicomponent Kardar-Parisi-Zhang universality in degenerate coupled condensates
The RG flows in Eq. (8) where T = 1, with the Cole–Hopf line X = 1 (red) and a line of fixed points with an emergent fluctuation dissipation relation X = Y (black). For the SCGLE, Quadrant I gives KPZ scaling in both modes, Quadrant IV is an STV-dominated phase, Quadrants II and III have a dynamical instability in the gapless modes, making the mapping inappropriate. Bare parameters which lie on the Cole–Hopf line in Quadrant I flow to the decoupled KPZ fixed point at (1, 1), denoted by the star. The point (0, 0) corresponds to an exceptional point, where \({\tilde{\theta }}_{1}\) and \({\tilde{\theta }}_{2}\) are decoupled in the rotated basis, and thus is an unstable fixed point describing a KPZ mode decoupled from an EW mode. The square at (1, − 1) is a fixed point predicted in Quadrant II where there is a complex Cole–Hopf solution, but is unstable and thus not considered further.
