The Effective Theory of Gravity: Gravitational Vacuum Condensate Stars, Scalar Gravitational Waves & Dynamical Vacuum Energy
Date: 07 JULY 2025 from 14:00 to 15:00
Event location: Sala IR-2A
Classical general relativity acquires an infrared relevant addition from the quantum conformal anomaly, which activates the scalar conformal part of the metric, and is responsible for macroscopically large effects on light cones and black hole horizons. A consistent low energy EFT description of vacuum energy, insensitive to ultra short distance scales, also requires that the cosmological `constant' in Einstein's theory be replaced by an exact 4-form abelian gauge field strength F = dA. If A is identified as the Chern-Simons 3--form of the Euler class, defined in terms of the spin connection, the conformal anomaly of massless fermions contributes a J . A interaction to the effective action. Due to the extreme blueshifting of local frequencies in the near-horizon region of a `black hole,' the lightest fermions of the Standard Model can be treated as massless there, providing a 3-current source for the `Maxwell' equation d *F = *J. In this phase boundary region, torsion is activated, and both F and vacuum energy can change rapidly. The Schwarzschild black hole horizon is thereby replaced by a surface, with a positive surface tension, separating regions of differing vacuum energy. The result is a gravitational vacuum condensate star, a cold, compact, horizonless object with a p= -rho non-singular de Sitter, zero entropy, and thin quantum phase boundary layer at the Schwarzschild radius, consistent with quantum theory. The activation of the conformal scalar degree of freedom in the EFT also predicts the existence of a spin-0 `breather' mode polarization of gravitational waves in addition to the transvese, tracefree polarizations of GR, at levels that may be detectable by the current and planned LSC array of 3 or more GW detectors. The variable dynamical vacuum energy of the EFT has consequences for cosmology as well, distinguishing it from the fixed LambdaCDM model, which can be tested by observations.