The event horizon of a black hole behaves like a thermostat: it has a temperature and an entropy. In 1995, physicist Ted Jacobson showed that if you apply the ordinary rule of heat transfer to this thermostat, Einstein's equations of gravity follow from it on their own. Heat, temperature and a measure of disorder on the boundary of an accessible region of space: that, it turns out, is what attraction is made of.
In the new work this idea is taken further. The author replaces the standard entropy formula with a more general one and watches how gravity changes. It turns out that any change in entropy is equivalent to a change in the strength of the gravitational coupling. It is as if the thermostat's scale set the stiffness of a spring.
Ordinary corrections to entropy do not save us from infinite density at the beginning of the Universe. So the author constructs a new entropy in which the horizon is made of tiny quantum oscillators, and a minimum area plays the role of the ground state, like the zero-point energy of a vibrating string. Even an empty horizon cannot be entirely empty.
At late times the model reproduces the behavior of loop quantum cosmology: at high density, expansion slows down. But unlike that theory, there is no bounce here, only an inflationary phase. A horizon-thermostat with a new entropy scale rewrites the history of the Universe, with no singularity at the beginning.
The minimum horizon area A₀ plays a role analogous to the ground-state energy of a quantum harmonic oscillator: even in an "empty" horizon there remains an irreducible quantum activity. In the model, allowed areas are quantized as A = nA₀, where n ≥ 2, meaning the n=1 state is forbidden due to logarithmic divergence.
The idea that gravity arises from horizon thermodynamics echoes Liu Cixin's novel The Three-Body Problem, where an alien civilization manipulates fundamental laws through curled-up dimensions. Here, horizon entropy acts as code that rewrites gravity.