A thermodynamic origin for the Cohen-Kaplan-Nelson bound

The Cohen-Kaplan-Nelson bound is imposed on the grounds of logical consistency (with classical General Relativity) upon local quantum field theories. This paper puts into context a thermodynamic principle applicable to with particular equation state in an expanding universe. achieved without overtly appealing either decreasing density states or minimum coupling requirement, though they might still be consistent results described. We do so by defining appropriate Helmholtz free energy which when extremized relative key parameter (the Hubble radius L) provides scaling formula for entropy (an exponent 'r' used text). deduce that CKN one solution this extremization problem r=3/2), but there are others r=2. establishes holographic applied cosmology minimizing universe canonical ensemble, assumption ultraviolet cutoff function causal horizon scale.