Comment on “Black Hole Entropy: A Closer Look”

  title={Comment on “Black Hole Entropy: A Closer Look”},
  author={Pedro Pessoa and Bruno Arderucio Costa},
In a recent paper (Entropy 2020, 22(1), 17), Tsallis states that entropy—as in Shannon or Kullback–Leiber’s definitions—is inadequate to interpret black hole entropy and suggests that a new non-additive functional should take the role of entropy. Here we counterargue by explaining the important distinction between the properties of extensivity and additivity; the latter is fundamental for entropy, while the former is a property of particular thermodynamical systems that is not expected for… 
Reply to Pessoa, P.; Arderucio Costa, B. Comment on “Tsallis, C. Black Hole Entropy: A Closer Look. Entropy 2020, 22, 17”
In the present Reply, the focus only onto the main erroneous claims by Pessoa and Costa in their recent Comment (Entropy 2020, 22, 1110).
Entropic Dynamics of Networks
A framework for the dynamics of graphs meant to represent a network derived from the principle of maximum entropy and the rate of transition is obtained taking into account the natural information geometry of probability distributions to apply to the Gibbs distribution of random graphs obtained with constraints on the node connectivity.
Statistical Mechanics of Unconfined Systems: Challenges and Lessons
Motivated by applications of statistical mechanics in which the system of interest is spatially unconfined, we present an exact solution to the maximum entropy problem for assigning a stationary


Black Hole Entropy: A Closer Look
A non-Boltzmannian entropic functional noted Sδ was applied to this complex system which exhibits the so-called area-law, based on the fact that the well known Bekenstein-Hawking entropy can be expressed as being proportional to the event horizon area divided by the square of the Planck length.
Laws of black hole thermodynamics in semiclassical gravity
  • B. Costa
  • Physics
    Classical and Quantum Gravity
  • 2020
The first and second laws of black hole thermodynamics are verified to emerge from a generic semiclassical theory of gravity for which a Hamiltonian can be defined. The first law is established for
Generalized gravitational entropy
A bstractWe consider classical Euclidean gravity solutions with a boundary. The boundary contains a non-contractible circle. These solutions can be interpreted as computing the trace of a density
Notes on black-hole evaporation
This paper examines various aspects of black-hole evaporation. A two-dimensional model is investigated where it is shown that using fermion-boson cancellation on the stress-energy tensor reduces the
Black holes and thermodynamics
There exists a set of striking similarities between the laws governing the equilibrium mechanics of stationary black holes and the classical laws of thermodynamics. While the full development of this
Gibbs vs Boltzmann Entropies
The status of the Gibbs and Boltzmann expressions for entropy has been a matter of some confusion in the literature. We show that: (1) the Gibbs H function yields the correct entropy as defined in
Zipf's law, power laws, and maximum entropy
Zipf's law, and power laws in general, have attracted and continue to attract considerable attention in a wide variety of disciplines - from astronomy to demographics to software structure to
Reply to C. Tsallis' "Conceptual Inadequacy of the Shore and Johnson Axioms for Wide Classes of Complex Systems"
A rebuttal of this work appears in entropy and argues that the Shore and Johnson axioms are inapplicable to a wide class of complex systems and highlights the errors in this reasoning.
The four laws of black hole mechanics
Expressions are derived for the mass of a stationary axisymmetric solution of the Einstein equations containing a black hole surrounded by matter and for the difference in mass between two
Axiomatic derivation of the principle of maximum entropy and the principle of minimum cross-entropy
Jaynes's principle of maximum entropy and Kullbacks principle of minimum cross-entropy (minimum directed divergence) are shown to be uniquely correct methods for inductive inference when new