Gl. Alberghi et al., Effective action and thermodynamics of radiating shells in general relativity - art. no. 124018, PHYS REV D, 6012(12), 1999, pp. 4018
An effective action is obtained for the area and mass aspect of a thin shel
l of radiating self-gravitating matter. On following a mini-superspace appr
oach, the geometry of the embedding space-time is not dynamical but fixed t
o be either Minkowski or Schwarzschild inside the shell and Vaidya in the e
xternal space filled with radiation. The Euler-Lagrange equations of motion
are discussed and shown to entail the expected invariance of the effective
Lagrangian under time reparametrization. They are equivalent to the usual
junction equations and suggest a macroscopic quasi-static thermodynamic des
cription. [S0556-2821(99)00324-0].