## Hemeroteca del mes septiembre, 2012

#### The Center is Everywhere

Por • 30 sep, 2012 • Category: Ambiente

«The Center is Everywhere» is a sculpture by Josiah McElheny, currently (through October 14, 2012) on exhibit at the Institute of Contemporary Art, Boston. The sculpture is based on data from the Sloan Digital Sky Survey (SDSS), using hundreds of glass crystals and lamps suspended from brass rods to represent the three-dimensional structure mapped by the SDSS through one of its 2000+ spectroscopic plugplates. This article describes the scientific ideas behind this sculpture, emphasizing the principle of the statistical homogeneity of cosmic structure in the presence of local complexity. The title of the sculpture is inspired by the work of the French revolutionary Louis Auguste Blanqui, whose 1872 book «Eternity Through The Stars: An Astronomical Hypothesis» was the first to raise the spectre of the infinite replicas expected in an infinite, statistically homogeneous universe. Puzzles of infinities, probabilities, and replicas continue to haunt modern fiction and contemporary discussions of inflationary cosmology.

#### Difference between three quantities

Por • 30 sep, 2012 • Category: Educacion

The notion of difference between two quantities plays a basic role in mathematics, consequently in all branches of human activity where the mathematics is applied. However the long stand question is: what is the difference between three (or more) quantities? The binary operation [a,b]=(a-b) possesses the following principal feature: with respect to the third quantity (c) this operation is decomposed into a sum of the same operations between (a) and (c), and (c)and (b), i.e., [a,b]=[a,c]+[c,b]. Denote by [a,b,c] difference between three quantities (a,b,c). With respect to additional quantity (d) this definition of the difference has to possess with the following property [a,b,c]=[d,b,c]+[a,d,c]+[a,b,d]. We prove that this property of difference between three (or n>2) quantities is satisfied by one of the features of Vandermonde determinant.

#### The Uncountability of the Unit Interval

Por • 27 sep, 2012 • Category: Filosofía

For any particularly interesting theorem one proof is never enough. Instead, the first proof sets the challenge to find a more elegant method that illuminates subtle features of the math, is simpler to understand, or even avoids using controversial subjects. In this paper we consider a subject that has attracted the attention of many mathematicians: the uncountability of the real numbers in the unit interval. We present the most exhaustive collection of proofs of this fact that we know. These range from Cantor’s three published proofs, including his famous diagonalization method, to more recent proofs that employ measure theory, game theory, algebra, and analysis.

#### Quantum Theory, namely the pure and reversible theory of information

Por • 27 sep, 2012 • Category: Opinion

After more than a century since its birth, Quantum Theory still eludes our understanding. If asked to describe it, we have to resort to abstract and ad hoc principles about complex Hilbert spaces. How is it possible that a fundamental physical theory cannot be described using the ordinary language of Physics? Here we offer a contribution to the problem from the angle of Quantum Information, providing a short non-technical presentation of a recent derivation of Quantum Theory from information-theoretic principles. The broad picture emerging from the principles is that Quantum Theory is the only standard theory of information compatible with the purity and reversibility of physical processes.

#### Is the Information Entropy the Same as the Statistical Mechanical Entropy?

Por • 27 sep, 2012 • Category: Crítica

It is shown that the standard expression for the information entropy, originally due to Shannon, is only valid for a particular set of states. For the general case of statistical mechanics, one needs to include an additional term in the expression for the entropy as a function of the probability. A simple derivation of the general formula is given.

#### Comment on the evidence of the Higgs boson at LHC

Por • 27 sep, 2012 • Category: Leyes

We comment on the Standard Model Higgs boson evidence from LHC. We propose that the new resonance at 125 GeV could be interpreted as a pseudoscalar meson with quantum number \$J^{PC} = 0^{- +}\$. We show that this pseudoscalar could mimic the decays of the Standard Model Higgs boson in all channels with the exception of the decay into two leptons that i. s strongly suppressed due to charge-conjugation invariance

#### A generalized statistical model for the size distribution of wealth

Por • 27 sep, 2012 • Category: Economía

In a recent paper in this journal [J. Stat. Mech. (2009) P02037] we proposed a new, physically motivated, distribution function for modeling individual incomes having its roots in the framework of the k-generalized statistical mechanics. The performance of the k-generalized distribution was checked against real data on personal income for the United States in 2003. In this paper we extend our previous model so as to be able to account for the distribution of wealth. Probabilistic functions and inequality measures of this generalized model for wealth distribution are obtained in closed form. In order to check the validity of the proposed model, we analyze the U.S. household wealth distributions from 1984 to 2009 and conclude an excellent agreement with the data that is superior to any other model already known in the literature.

#### Mursi reajusta sus vínculos con EE.UU.

Por • 27 sep, 2012 • Category: Política

La confusión mental estadounidense sobre Egipto terminó el fin de semana pasado, solo nueve días después que el presidente Barack Obama hiciera su famoso comentario en una entrevista televisada diciendo que no está seguro de que el Egipto post Hosni Mubarak sea un aliado de EE.UU. En una entrevista con The New York Times el sábado, el presidente egipcio Mohamed Mursi se ofreció a aclarar la confusión. Cuando se le preguntó si Egipto es un aliado, Mursi respondió sonriendo: “Depende de su definición de aliado”. Luego sugirió servicialmente que los dos países son “verdaderos amigos”.

#### El Dictatus Papae de Gregorio VII de 1075 y el Ad Heinricum IV de Benzo de Alba

Por • 27 sep, 2012 • Category: sociologia