Improved gravitational-wave constraints on higher-order curvature theories of gravity

Abstract

Gravitational wave observations of compact binaries allow us to test general relativity (and modifications thereof) in the strong and highly dynamical field regime of gravity. Here, we confront two extensions to general relativity, dynamical Chern-Simons, and Einstein-dilaton-Gauss-Bonnet theories, against the gravitational wave sources from the GWTC-1 and GWTC-2 catalogs by the LIGO-Virgo Collaboration. By stacking the posterior of individual events, we strengthen the constraint on the square root of the coupling parameter in Einstein-dilaton-Gauss-Bonnet gravity to ffiffiffiffiffiffiffiffiffiffiffi ffi α EdGB p < 1.7 km, but we are unable to place meaningful constraints on dynamical Chern-Simons gravity. Importantly, we also show that our bounds are robust to (i) the choice of general-relativity base waveform model, upon which we add modifications, (ii) unknown higher post-Newtonian order terms in the modifications to general relativity, (iii) the smallcoupling approximation, and (iv) uncertainties on the nature of the constituent compact objects.

Ghost of vector fields in compact stars

“…[43]. Effectively, this gauge undoes the Stueckelberg trick (7) and we only need to consider Eq. ( 5).…”

“…The first gravitational wave (GW) signal from a compact binary coalescence detected by the LIGO-Virgo collaboration [1] in 2015 opened a new vista into the nonlinear and highly dynamical regime of gravity. Moreover, and perhaps more excitingly, GWs now allow us to probe (or constrain) new physics beyond GR and the Standard Model [2][3][4][5][6][7]. This had so far been limited to astronomical probes either in the weak gravitational field and slow velocity in our Solar System or in the strong gravitational field, but small velocity and large separation regime of binary pulsars [8,9].…”

Effective Field Theory for the perturbations of a slowly rotating black hole

“…The strongest bound on α comes from the absence of any signal of scalar wave dipolar emission, sourced by that coupling, in black hole merger data. A recent analysis finds α (1.7 km) 2 [46] (see also refs. [12,47]).…”

Gravitational ringing of rotating black holes in higher-derivative gravity

“…the GR prediction that the geometry of a rotating black hole is given by the Kerr one, or even whether black objects are black holes at all [10]. In the light of these developments it is of great interest to study and identify what are the possible signatures of corrections to GR in gravitational wave signals [11][12][13][14][15][16][17][18][19].…”