Cosmological Constant from Entanglement Entropy
A derivation via Jacobson-Cai-Kim horizon thermodynamics
Derives the cosmological constant from the logarithmic correction to entanglement entropy, obtaining a prediction within 3% of the observed value with zero free parameters.
Mar 1, 2026 · Preprint
Plain English
This paper calculates the strength of dark energy from first principles — and gets an answer within 3% of what astronomers actually observe, with zero adjustable constants.
The problem
Dark energy makes up about 70% of the universe and is causing space to expand faster and faster. Physicists describe its strength with a single number called the cosmological constant. The trouble is, when they try to calculate this number using standard quantum physics, the answer is wrong by a factor of 10 followed by 120 zeros. That is the single worst prediction in the history of science.
The key idea
When you split space into two regions, the quantum fields living on the boundary become entangled. That entanglement carries a tiny correction term — a logarithmic blip that is completely invisible at small scales but becomes significant at the scale of the entire observable universe. This paper shows that blip is dark energy.
What the paper does
It adds up the contributions from every known particle in the Standard Model — photons, electrons, quarks, neutrinos, the Higgs, the W and Z bosons, gluons — and feeds them into the formula. No free parameters. No knobs to turn. The Standard Model alone gets within 3% of the observed value. Including the graviton brackets the observation: 0.97 < 1.0 < 1.07.
Why it matters
If confirmed, this means dark energy is not some exotic new substance or force. It is a natural, unavoidable consequence of quantum entanglement at the largest scales. The universe accelerates because quantum information has a built-in cost at the cosmic horizon — and that cost is exactly what we call dark energy.
What could go wrong
This is a preprint and has not yet been peer-reviewed. The calculation relies on heat kernel counting for fermion area-law coefficients (which cannot be independently verified on the lattice) and on Jacobson-style horizon thermodynamics at cosmological scales. The DESI 2024 hint of w₀ ≠ −1 (2.1σ tension) is the most likely avenue for falsification. Independent replication and observational tests will be decisive.