Infrared dynamics of the strongly open phase

Determine the infrared behavior and construct an analytical blocked action that captures the infrared limit of the strongly open phase in the self-interacting scalar field theory studied via the renormalization group within the Closed Time Path formalism.

Background

The renormalization-group analysis reveals a separatrix between weakly and strongly open phases, with non-relativistic scaling regimes and environment-induced phase transitions. In the strongly open phase, open interaction channels drive the flow into a regime where the current low-order Landau–Ginzburg-type ansatz becomes insufficient.

The authors explicitly note their inability to access the infrared limit of the strongly open phase with the present ansatz, indicating the need for an improved analytical form of the blocked action to reconstruct the IR dynamics.