Queen Mary University of London mathematician Professor Ginestra Bianconi has outlined how gravity can be reconciled with the second law of thermodynamics within her “Gravity from Entropy” (GfE) framework, a quantum-gravity theory that treats gravity as an emergent property of entropy rather than a fundamental force.

Albert Einstein once called the second law of thermodynamics — which holds that entropy, or disorder, always increases over time — the most unshakeable law in physics. Reconciling that principle with gravity has long been a central challenge in theoretical physics, one that gained new urgency following Jacob Bekenstein and Stephen Hawking’s discovery that black holes carry entropy proportional to the area of their event horizons.

Bianconi’s new work proposes that while the total entropy of the universe increases over time, entropy per unit volume can decrease — allowing complex structures such as galaxies and living organisms to emerge without violating the second law.

The GfE framework derives gravity from what Bianconi calls Quantum Geometric Relative Entropy (QGRE), a measure of the difference between the true spacetime metric and a metric induced by matter. At low energies, the theory reduces to Einstein’s General Relativity, but it also includes a dynamical dark-energy term that becomes relevant beyond that limit.

Applying the framework to Friedmann–Robertson–Walker cosmological spacetimes — the standard model used to describe an expanding universe — Bianconi found a first law of thermodynamics in which dynamical dark energy plays the role of internal energy, and QGRE serves as a local measure of entropy per unit volume.

“This work shows that gravity and thermodynamics are not just compatible, but deeply intertwined within the Gravity from Entropy framework,” said Bianconi.

Journal: Physical Review D
DOI: 10.1103/26kn-thgp
Article Title: Thermodynamics of the gravity from entropy theory
Publication Date: 17 July 2026

Source: EurekAlert