131 research outputs found
Nomenclatural and taxonomic review of Passifloraceae species illustrated and described by Vellozo in Flora Fluminensis
Black hole thermodynamical entropy
As early as 1902, Gibbs pointed out that systems whose partition function
diverges, e.g. gravitation, lie outside the validity of the Boltzmann-Gibbs
(BG) theory. Consistently, since the pioneering Bekenstein-Hawking results,
physically meaningful evidence (e.g., the holographic principle) has
accumulated that the BG entropy of a black hole is
proportional to its area ( being a characteristic linear length), and
not to its volume . Similarly it exists the \emph{area law}, so named
because, for a wide class of strongly quantum-entangled -dimensional
systems, is proportional to if , and to if
, instead of being proportional to (). These results
violate the extensivity of the thermodynamical entropy of a -dimensional
system. This thermodynamical inconsistency disappears if we realize that the
thermodynamical entropy of such nonstandard systems is \emph{not} to be
identified with the BG {\it additive} entropy but with appropriately
generalized {\it nonadditive} entropies. Indeed, the celebrated usefulness of
the BG entropy is founded on hypothesis such as relatively weak probabilistic
correlations (and their connections to ergodicity, which by no means can be
assumed as a general rule of nature). Here we introduce a generalized entropy
which, for the Schwarzschild black hole and the area law, can solve the
thermodynamic puzzle.Comment: 7 pages, 2 figures. Accepted for publication in EPJ
Atrazine bound residues formation and dissipation in subtropical soil under swine wastewater application
Épocas de poda e uso da irrigação em figueira 'roxo de valinhos' na região de Botucatu, SP
Perfil dos cães sororreagentes para aglutininas anti-Leptospira interrogans em Belo Horizonte, Minas Gerais, 2001/2002
Detection of cheese whey and caseinomacropeptide in fermented milk beverages using high performance liquid chromatography
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