5,511 research outputs found
Charged rotating black holes in higher dimensions
We use a recent implementation of the large expansion in order to
construct the higher-dimensional Kerr-Newman black hole and also new charged
rotating black bar solutions of the Einstein-Maxwell theory, all with rotation
along a single plane. We describe the space of solutions, obtain their
quasinormal modes, and study the appearance of instabilities as the horizons
spread along the plane of rotation. Generically, the presence of charge makes
the solutions less stable. Instabilities can appear even when the angular
momentum of the black hole is small, as long as the charge is sufficiently
large. We expect that, although our study is performed in the limit
, the results provide a good approximation for charged rotating
black holes at finite .Comment: 21 pages, 1 figur
Critical exponents for the long-range Ising chain using a transfer matrix approach
The critical behavior of the Ising chain with long-range ferromagnetic
interactions decaying with distance , , is investigated
using a numerically efficient transfer matrix (TM) method. Finite size
approximations to the infinite chain are considered, in which both the number
of spins and the number of interaction constants can be independently
increased. Systems with interactions between spins up to 18 sites apart and up
to 2500 spins in the chain are considered. We obtain data for the critical
exponents associated with the correlation length based on the Finite
Range Scaling (FRS) hypothesis. FRS expressions require the evaluation of
derivatives of the thermodynamical properties, which are obtained with the help
of analytical recurrence expressions obtained within the TM framework. The Van
den Broeck extrapolation procedure is applied in order to estimate the
convergence of the exponents. The TM procedure reduces the dimension of the
matrices and circumvents several numerical matrix operations.Comment: 10 pages, 2 figures, Conference NEXT Sigma Ph
Electoral Libels: A Comparative Study of the English and Ecuadorian Law of Defamation
English and Ecuadorian defamation law have developed very different mechanisms to resolve the tension between the right to freedom of speech and the protection of private life. Ordinarily this would not be too surprising, insofar as it is natural that different countries will have different legal institutions. However, this divergence becomes relevant because both jurisdictions claim to be bound by virtually the same human rights obligations when it comes to speech related to matters of public interest. For this reason, this article focuses on speech issued during electoral campaigns—perhaps the best example of public interest speech—in order to assess how different jurisdictions prioritise between the different rights and interests at play in these kind of defamation cases
Analytical approach to directed sandpile models on the Apollonian network
We investigate a set of directed sandpile models on the Apollonian network,
which are inspired on the work by Dhar and Ramaswamy (PRL \textbf{63}, 1659
(1989)) for Euclidian lattices. They are characterized by a single parameter
, that restricts the number of neighbors receiving grains from a toppling
node. Due to the geometry of the network, two and three point correlation
functions are amenable to exact treatment, leading to analytical results for
the avalanche distributions in the limit of an infinite system, for .
The exact recurrence expressions for the correlation functions are numerically
iterated to obtain results for finite size systems, when larger values of
are considered. Finally, a detailed description of the local flux properties is
provided by a multifractal scaling analysis.Comment: 7 pages in two-column format, 10 illustrations, 5 figure
El comentario de Santayana y Spinosa: (1568) al Tratado de la esfera de Sacrobosco
Durante el siglo XVI se hicieron en España varios comentarios y traducciones al Tratado de la
esfera de Johannes de Sacrobosco (Martins, 2004). Hubo una única edición en latÃn, comentada,
de Pedro de Espinosa (1550) y se publicaron diversas traducciones parciales o, comentadas. Las
del último tipo son tres: de Jerónimo de Chaves (1545), de Rodrigo Saenz de Santayana y
Spinosa (1568) y de Ginés de Rocarnora y Torrano (1599).
El objetivo de este trabajo es analizar especialmente una de estas -la que fue publicada en
el 1568 por Santayana y Spinosa - discutiendo sus peculiaridades y presentando una breve
comparación con las otras dos versiones castellanas de los quinientos
- …