Gravitational wave constraints on corrections to Bekenstein-Hawking Area Formula in classical F(R) gravity and quantum GR : implications for theory parameters

Abstract

This contribution considers constraints from analyses of gravitational wave data from binary black hole coalescence, on possible corrections to the Bekenstein-Hawking Area Formula for black hole entropy. Most recent analyses of gravitational wave data from the LVK Consortium appear to confirm the Hawking Area Theorem for black holes at a $5 σ$ accuracy, for the `loudest' signal (SNR of the order of $80$) of binary black hole merger inherent in the recent observation GW250114. Amalgamating this result with Bekenstein's ideas of black hole entropy and the generalized second law of thermodynamics, we constrain leading inverse area corrections for large horizon area spherical black hole solutions of classical $F(R)$ gravity, using the Wald entropy function formalism. The implementation of the observational constraints entails the notion of `absolute consistency' which we introduce and contrast with `relative consistency'. This absolute consistency criterion is shown to relate some of the parameters of $F(R)$ gravity. Next we consider leading quantum general relativistic corrections to the Area formula, arising both from the non-perturbative matter-free Loop Quantum Gravity and matter-dependent, perturbative Entanglement entropy approaches. Combining the leading logarithmic corrections in horizon area (for large areas) from both approaches, and imposing absolute consistency with the observational validation of the Area Theorem, is shown to lead to significant restrictions on the spin and number of species of Beyond Standard Model spectrum of elementary particles, some of which are often assumed to be Dark Matter candidates.