2.6k citations
Counting papers with at most 25 authors, so collaboration author lists do not stand in for the people here.
- Instituto Superior TécnicoPT388 papers
- Centro de Física Teórica de Partículas54 papers
- University of ViennaAT37 papers
- Centre National de la Recherche ScientifiqueFR34 papers
- University of LisbonPT34 papers
- University of MississippiUS31 papers
- Universitat de ValènciaES27 papers
- California Institute of TechnologyUS25 papers
- University of CoimbraPT19 papers
- European Organization for Nuclear ResearchCH18 papers
- Instituto de TelecomunicaçõesPT18 papers
- Instituto Politécnico de LisboaPT17 papers
21 papers · 1 filter
On the minimum number of colors for knots
Louis H. Kauffman, Pedro Lopes
In this article we take up the calculation of the minimum number of colors needed to produce a non-trivial coloring of a knot. This is a knot invariant and we use the torus knots o…
On Self-Regulated Swarms, Societal Memory, Speed and Dynamics
Vitorino Ramos, Carlos Fernandes, Agostinho C. Rosa
We propose a Self-Regulated Swarm (SRS) algorithm which hybridizes the advantageous characteristics of Swarm Intelligence as the emergence of a societal environmental memory or cog…
Involutions on numerical Campedelli surfaces
Alberto Calabri, Margarida Mendes Lopes, Rita Pardini
Numerical Campedelli surfaces are minimal surfaces of general type with p_g=0 (and so q=0) and K^2=2. Although they have been studied by several authors, their complete classificat…
Indistinguishable Particles in Quantum Mechanics: An Introduction
Y. Omar
In this article, we discuss the identity and indistinguishability of quantum systems and the consequent need to introduce an extra postulate in Quantum Mechanics to correctly descr…
Mu-tau antisymmetry and neutrino mass matrices
Walter Grimus, Satoru Kaneko, Luis Lavoura +2
Using the seesaw mechanism and a discrete symmetry, we construct a class of models for the neutrino mass matrix where the inverse of that matrix is the sum of a mu-tau antisymmetri…
Self-Similar Solutions to Curvature Flow of Convex Hypersurfaces
Guanghan Li, Isabel Salavessa, Chuanxi Wu
We classify the self-similar solutions to a class of Weingarten curvature flow of connected compact convex hypersurfaces, isometrically immersed into space forms with non-positive…
Multidimensional continued fractions, dynamical renormalization and KAM theory
K Khanin, J Lopes-Dias, J Marklof
The disadvantage of `traditional' multidimensional continued fraction algorithms is that it is not known whether they provide simultaneous rational approximations for generic vecto…
A model realizing the Harrison-Perkins-Scott lepton mixing matrix
W. Grimus, L. Lavoura
We present a supersymmetric model in which the lepton mixing matrix obeys, at the seesaw scale, the Harrison--Perkins--Scott \textit{Ansatz}--vanishing , maximal atmosp…
Is it possible to predict the sign of the Matter-Antimatter Asymmetry in the Universe?
Pavel Fileviez Perez
I investigate the possibility to define the sign of the leptonic asymmetry by the low energy parameters. It is shown that in the context of the minimal renormalizable SO(10) model…
Spectroscopic Observations and Analysis of the Unusual Type Ia SN 1999ac
The Supernova Cosmology Project, :, G. Garavini +55
We present optical spectra of the peculiar Type Ia supernova (SN Ia) 1999ac. The data extend from -15 to +42 days with respect to B-band maximum and reveal an event that is unusual…
The Geometry of Crashes - A Measure of the Dynamics of Stock Market Crises
Tanya Araújo, Francisco Louçã
This paper investigates the dynamics of stocks in the S&P500 index for the last 30 years. Using a stochastic geometry technique, we investigate the evolution of the market space an…
On 2-Dimensional Homotopy Invariants of Complements of Knotted Surfaces
João Faria Martins
We prove that if is a CW-complex and is a 0-cell of , then the crossed module does not depend on the cellular decomposition of up to free products wit…
Black holes and fundamental physics
José P. S. Lemos
We give a review of classical, thermodynamic and quantum properties of black holes relevant to fundamental physics.
Moduli evolution in the presence of flux compactifications
T. Barreiro, B. de Carlos, E. J. Copeland +1
We study the cosmological evolution of the volume moduli in a class of recently proposed Inflationary Universe models arising out of Type IIB string theory, where a number of the m…
A class of exact solutions of Einstein's field equations in higher dimensional spacetimes, d: Majumdar-Papapetrou solutions
Jose' P. S. Lemos, Vilson T. Zanchin
The Newtonian theory of gravitation and electrostatics admit equilibrium configurations of charged fluids where the charge density can be equal to the mass density, in appropriate…
Recent Results from the SIMPLE Dark Matter Search
TA Girard, F. Giuliani, J. I. Collar
SIMPLE is an experimental search for evidence of spin-dependent dark matter, based on superheated droplet detectors using CClF. We report preliminary results of a 0.6 k…
The Tolman-Bondi--Vaidya Spacetime: matching timelike dust to null dust
Sijie Gao, Jose' P. S. Lemos
The Tolman-Bondi and Vaidya solutions are two solutions to Einstein equations which describe dust particles and null fluid, respectively. We show that it is possible to match the t…
S3 x Z2 model for neutrino mass matrices
W. Grimus, L. Lavoura
We propose a model for lepton mass matrices based on the seesaw mechanism, a complex scalar gauge singlet and a horizontal symmetry $S_3 \times \mathbbm{Z}_2$. In a suitable weak b…
Local conditions for the generalized covariant entropy bound
Sijie Gao, Jose' P. S. Lemos
A set of sufficient conditions for the generalized covariant entropy bound given by Strominger and Thompson is as follows: Suppose that the entropy of matter can be described by an…
Two predictive supersymmetric S3 x Z2 models for the quark mass matrices
Luis Lavoura, Ernest Ma
We propose two simple models for the quark mass matrices which may be implemented through an S3 x Z2 symmetry in a supersymmetric context. Each model has eight parameters and, ther…
Twenty-one centimeter tomography with foregrounds
Xiaomin Wang, Max Tegmark, Mario Santos +1
Twenty-one centimeter tomography is emerging as a powerful tool to explore the end of the cosmic dark ages and the reionization epoch, but it will only be as good as our ability to…