An estimation of the logarithmic timescale in an ergodic dynamics

An estimation of the logarithmic timescale in quantum systems having an ergodic dynamics in the semiclassical limit of quasiclassical large parameters, is presented. The estimation is based on the existence of finite generators for ergodic measure-preserving transformations having a finite Kolmogorov--Sinai (KS) entropy and on the time rescaling property of the KS-entropy. The results are in agreement with the obtained in the literature but with a simpler mathematics and within the context of the ergodic theory

Gaussian ensembles distributions from mixing quantum systems

In the context of the mixing dynamical systems we present a derivation of the Gaussian ensembles distributions from mixing quantum systems having a classical analog that is mixing. We find that mixing factorization property is satisfied for the mixing quantum systems expressed as a factorization of quantum mean values. For the case of the kicked rotator and in its fully chaotic regime, the factorization property links decoherence by dephasing with Gaussian ensembles in terms of the weak limit, interpreted as a decohered state. Moreover, a discussion about the connection between random matrix theory and quantum chaotic systems, based on some attempts made in previous works and from the viewpoint of the mixing quantum systems, is presented

How education shaped communist Cuba

F is for Fidel, Y is for Yanqui. This mantra used for teaching the alphabet in revolutionary Cuba shows just how far its educational divide with the U.S. has stretched. No sector illustrates better how Cuba and the U.S. have grown apart in over 50 years than education. Cuba claims today that its academic standards are among the highest in the world, and the country has educated tens of thousands of foreign students, mostly in medicine. U.S. policymakers know little about the methods used in Cuban education, nor what practical opportunities for collaboration in research and business might exist. With the agreement the two countries made last December to restore diplomatic relations, that may be about to change

Lepton flavor violating Higgs Boson Decays in Supersymmetric High Scale Seesaw Models

Within the MSSM, we have evaluated the decay rates for the lepton flavour violating Higgs boson decays (LFVHD) $h \rightarrow l_i l_j$ where $l_{i,j}$ are charged leptons and $i\neq j$. This has been done in a model independent (MI) way as well as in supersymmetric high scale seesaw models, in particular Type I see-saw model. Lepton flavour violation (LFV) is generated by non-diagonal entries in the mass matrix of the sleptons. In a first step we use the model independent approach where LFV (off-diagonal entries in the mass matrix) is introduced by hand while respecting the direct search constraints from the charged lepton flavor violating (cLFV) processes. In the second step we use high scale see-saw models where LFV is generated via renormalization group equations (RGE) from the grand unification scale (GUT) down to electroweak scale. cLFV decays are the most restrictive ones and exclude a large part of the parameter space for the MI as well as the high scale see-saw scenarios. Due to very strict constraints from cLFV, it is difficult to find large corrections to LFVHD. This applies in particular to $h \rightarrow \tau \mu$ where hints of an excess have been observed. If this signal is confirmed, it could not be explained with the models under investigation.Comment: Accepted for publication in Journal of Particle Physic