Several independent semiclassical arguments converge on $$\boxed{\Delta A=8\pi l_{\mathrm{Pl}}^2}, \qquad l_{\mathrm{Pl}}^2=\frac{G\hbar}{c^3}$$ I got interested in this reading the 2018 paper Bekenstein, I, and the quantum of black-hole surface area . Even though I disagree with Hod, its a great paper. Honourable mentions also go to: The Physical Interpretation of the Spectrum of Black Hole Quasinormal Modes , 2008 The Off-Shell Black Hole , 1994 On Black Hole Spectroscopy via Adiabatic Invariance , 2012 An Analytical Computation of Asymptotic Schwarzschild Quasinormal Frequencies , 2003 Asymptotic Black Hole Quasinormal Frequencies , 2003 1. Horizon Action Near any nonextremal horizon, imaginary time turns the normal geometry into a plane: $$ds_E^2\simeq d\rho^2+\rho^2d\Theta^2+\cdots.$$ Smoothness requires one horizon cycle: $$\oint d\Theta=2\pi.$$ The gravitational action identifies the momentum conjugate to $\The...
We previously discussed Verlinde's connection of the MOND acceleration scale to the entropy of de Sitter space. A different route appears in superfluid dark matter (a 2026 review is here ), where baryons interact with a phonon field whose nonlinear dynamics generate a MOND-like force. The superfluid theory introduces a characteristic scale $\Lambda_{\rm SF}$, which must be of order meV to reproduce the MOND scale. This is also the order of the vacuum-energy scale, $\rho_{\rm DE}^{1/4}\sim{\rm meV}$. So, we postulate $\Lambda_{\rm SF}^4=\rho_{\rm DE}$. To be clear, the idea of a unified dark sector is not new , e.g. a 2019 Unified Superfluid Dark Sector , 2026 A solid unification of the dark sector , and 2026 Unified dark sector approach to cosmological tensions among many others. What we do here is identify the MOND phonon scale exactly with vacuum energy, plus postulate a dimensionless infrared response coefficient. So, let $\...