Maximum rate of entropy emission

Abstract It is shown that adding hair like electric charge or angular momentum to the black hole decreases the amount of entropy emission. This motivates us to study the emission rate of entropy from black holes and conjecture a maximum limit (upper bound) on the rate of local entropy emission ( S ) for thermal systems in four dimensional space time and argue that this upper bound is S ≃ k B c 5 ħ G . Also by considering Renyi entropy, it is shown that Bekenstein–Hawking entropy leads to a maximum limit for the rate of entropy emission. We also suggest an upper bound on the surface gravity of the black holes which is called Planck surface gravity. Finally we obtain a relation between maximum rate of entropy emission, Planck surface gravity and Planck temperature of black holes.