Theory-agnostic framework for dynamical scalarization of compact binaries

Abstract

Gravitational wave observations can provide unprecedented insight into the fundamental nature of gravity and allow for novel tests of modifications to General Relativity. One proposed modification suggests that gravity may undergo a phase transition in the strong-field regime; the detection of such a new phase would comprise a smoking-gun for corrections to General Relativity at the classical level. Several classes of modified gravity predict the existence of such a transition-known as spontaneous scalarization-associated with the spontaneous symmetry breaking of a scalar field near a compact object. Using a strong-field-agnostic effective-field-theory approach, we show that all theories that exhibit spontaneous scalarization can also manifest dynamical scalarization, a phase transition associated with symmetry breaking in a binary system. We derive an effective pointparticle action that provides a simple parametrization describing both phenomena, which establishes a foundation for theory-agnostic searches for scalarization in gravitational-wave observations. This parametrization can be mapped onto any theory in which scalarization occurs; we demonstrate this point explicitly for binary black holes with a toy model of modified electrodynamics.

Dynamical descalarization in binary black hole mergers

“…This is currently under study [59]. It would be interesting to frame this effect within the effective field theory (EFT) of [62] or in a post-Newtonian framework [63][64][65], although the latter may not be suitable for the modeling of a nonlinear dynamical scalarization process.…”

Black hole sensitivities in Einstein-scalar-Gauss-Bonnet gravity

“…Our results are important for the PN description of black hole binaries in ESGB gravity [43, 47-49, 97, 98], including gravitational waveform predictions [49,50], al-lowing to finally specialize them to scalarized black hole binaries. Our work could also be used to develop an effective action model [99] of dynamical black hole descalarization [57] and explore further the differences with respect to neutron star binaries in scalar-tensor theories [100][101][102][103][104][105] that predict spontaneous scalarization [106].…”

Neutron Stars in Scalar-Tensor Theories: Analytic Scalar Charges and Universal Relations

“…One may also apply the calculation to spontaneous vectorization [40,71,72], tensorization [73], or spinorization [74]. Another direction of extension might be to consider analytic representation for the dynamical/induced scalarization [75][76][77][78][79][80] in compact binary mergers. Finally, the parameter region of the coupling parameter β 0 that gives rise to spontaneous scalarization in the scalartensor theories studied here has been shown to be inconsistent with solar system experiments if one includes cosmological evolution of the scalar field [78,[81][82][83][84].…”