No evidence for violation of the second law in extended black hole thermodynamics

Abstract

Recently a number of papers have claimed that the horizon area -and thus the entropy -of near extremal black holes in anti-de Sitter spacetimes can be reduced by dropping particles into them. In this note we point out that this is a consequence of an underlying assumption that the energy of an infalling particle changes only the internal energy of the black hole, whereas a more physical assumption would be that it changes the enthalpy (mass). In fact, under the latter choice, the second law of extended black hole thermodynamics is no longer violated.

Weak cosmic censorship conjecture for the novel 4D charged Einstein–Gauss–Bonnet black hole with test scalar field and particle

“…The viewpoint was opposed by Page et al. They argued that when a particle is dropped into a black hole, it is the enthalpy that increases by the particle energy instead of the internal energy [89]. The argument of Page et al preserves the second law of black hole thermodynamics naturally.…”

Bulk entropy is crucial to validate the second law of the extended black hole thermodynamics

“…During this process more entropy is produced than the change in the black hole entropy. The modified second law of thermodynamics for black holes only gives a complete picture provided the entropy of the environment is included in order to preserve the second law (see also [19]).…”

Thermodynamics of Schwarzschild black hole surrounded by quintessence with generalized uncertainty principle

“…Black holes are probably the most mysterious objects in the universe. In recent years, we have observed an increase in the studies which examine black hole physics and thermodynamics in the modern cosmology literature [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. The basic assumption in these studies is that: "black holes could be taken as a thermal system, so the well-known thermodynamics laws could be used to interpret their nature".…”