Thermodynamics of Local Causal Horizons

Understand

We propose an expression for the entropy density associated with the Local Causal Horizons in any diffeomorphism invariant theory of gravity.

• If the black-hole entropy of the theory satisfies the physical process version of the first law of thermodynamics then our proposed entropy satisfies the Clausius relation.
• Thus, our study shows that the thermodynamic nature of the spacetime horizons is not restricted to the black holes; it also applies to the local causal horizons in the neighborhood of any point in the spacetime.