# Thermodynamics of quantum spacetime histories

@article{Smolin2015ThermodynamicsOQ,
title={Thermodynamics of quantum spacetime histories},
author={Lee Smolin},
journal={Physical Review D},
year={2015},
volume={96},
pages={104042}
}
• L. Smolin
• Published 13 October 2015
• Physics
• Physical Review D
We show that the simplicity constraints, which define the dynamics of spin foam models, imply, and are implied by, the first law of thermodynamics, when the latter is applied to causal diamonds in the quantum spacetime. This result reveals an intimate connection between the holographic nature of gravity, as reflected by the Bekenstein entropy, and the fact that general relativity and other gravitational theories can be understood as constrained topological field theories. To state and derive…
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