Two-dimensional Conformal Field Theories on AdS_{2d+1} Backgrounds

Various exact two-dimensional conformal field theories with AdS_{2d+1} target space are constructed. These models can be solved using bosonization techniques. Some examples are presented that can be used in building perturbative superstring theories with AdS backgrounds, including AdS_5.Comment: 36 pages, harvma

Spontaneous electro-weak symmetry breaking and cold dark matter

In the standard model, the weak gauge bosons and fermions obtain mass after spontaneous electro-weak symmetry breaking, which is realized through one fundamental scalar field, namely Higgs field. In this paper we study the simplest scalar cold dark matter model in which the scalar cold dark matter also obtains mass through interaction with the weak-doublet Higgs field, the same way as those of weak gauge bosons and fermions. Our study shows that the correct cold dark matter relic abundance within $3\sigma$ uncertainty ($0.093 < \Omega_{dm} h^2 < 0.129$) and experimentally allowed Higgs boson mass ($114.4 \le m_h \le 208$ GeV) constrain the scalar dark matter mass within $48 \le m_S \le 78$ GeV. This result is in excellent agreement with that of W. de Boer et.al. ($50 \sim 100$ GeV). Such kind of dark matter annihilation can account for the observed gamma rays excess ($10\sigma$) at EGRET for energies above 1 GeV in comparison with the expectations from conventional Galactic models. We also investigate other phenomenological consequences of this model. For example, the Higgs boson decays dominantly into scalar cold dark matter if its mass lies within $48 \sim 64$ GeV.Comment: 4 Revtex4 pages, refs adde

Critical behavior at Mott-Anderson transition: a TMT-DMFT perspective

We present a detailed analysis of the critical behavior close to the Mott-Anderson transition. Our findings are based on a combination of numerical and analytical results obtained within the framework of Typical-Medium Theory (TMT-DMFT) - the simplest extension of dynamical mean field theory (DMFT) capable of incorporating Anderson localization effects. By making use of previous scaling studies of Anderson impurity models close to the metal-insulator transition, we solve this problem analytically and reveal the dependence of the critical behavior on the particle-hole symmetry. Our main result is that, for sufficiently strong disorder, the Mott-Anderson transition is characterized by a precisely defined two-fluid behavior, in which only a fraction of the electrons undergo a "site selective" Mott localization; the rest become Anderson-localized quasiparticles.Comment: 4+ pages, 4 figures, v2: minor changes, accepted for publication in Phys. Rev. Let

Cancellation of quantum mechanical higher loop contributions to the gravitational chiral anomaly

We give an explicit demonstration, using the rigorous Feynman rules developed in~\0^{1}, that the regularized trace \tr \gamma_5 e^{-\beta \Dslash^2} for the gravitational chiral anomaly expressed as an appropriate quantum mechanical path integral is $\beta$-independent up to two-loop level. Identities and diagrammatic notations are developed to facilitate rapid evaluation of graphs given by these rules.Comment: 10 pages, LaTeX and psfig (many figures

Dark matter cores in the Fornax and Sculptor dwarf galaxies: joining halo assembly and detailed star formation histories

We combine the detailed Star Formation Histories of the Fornax and Sculptor dwarf Spheroidals with the Mass Assembly History of their dark matter (DM) halo progenitors to estimate if the energy deposited by Supernova type II (SNeII) is sufficient to create a substantial DM core. Assuming the efficiency of energy injection of the SNeII into DM particles is $\epsilon_{\rm gc}=0.05$, we find that a single early episode, $z \gtrsim z_{\rm infall}$, that combines the energy of all SNeII due to explode over 0.5 Gyr, is sufficient to create a core of several hundred parsecs in both Sculptor and Fornax. Therefore, our results suggest that it is energetically plausible to form cores in Cold Dark Matter (CDM) halos via early episodic gas outflows triggered by SNeII. Furthermore, based on CDM merger rates and phase-space density considerations, we argue that the probability of a subsequent complete regeneration of the cusp is small for a substantial fraction of dwarf-size haloes.Comment: ApJL accepted versio

Demonstration project on epilepsy in Brazil - WHO/ILAE/IBE Global Campaign Against Epilepsy - A foreword

In 2002, ASPE (Assistência à Saúde de Pacientes com Epilepsia)* initiated an Epilepsy Demonstration Project (DP) in Brazil as part of the Global Campaign Against Epilepsy "Epilepsy out of the Shadows", led by the World Health Organization (WHO), the International League Against Epilepsy (ILAE) and the International Bureau for Epilepsy (IBE)1-4. Demonstration Projects have been carried out in several countries and their main aim is to develop treatment models for people with epilepsy in primary health care settings, improving the quality of life of people with epilepsy and their families5-9. The project in Brazil has targeted areas in Campinas and São José do Rio Preto municipalities, both in São Paulo State, in Southeastern region8. A task force has been established to assess strategies to expand this nationwide. The DP was carried out in six phases as shown in Figure 1. The Brazilian DP was officially closed during the IV Workshop of the WHO/ILAE/IBE Global Campaign Against Epilepsy "Epilepsy out of the Shadows", held on May 4-5th 2006, in Campinas. The workshop reviewed the results of the project and discussed the establishment of a National Epilepsy Policy. This supplement presents some results from all phases of the Brazilian DP which were discussed during the Workshop. In brief, we believe that the DP had an impact in our society and brought a new perspective on epilepsy. Awareness campaigns are now carried out on September 9th (Epilepsy Awareness Day) annually in many sites around the country. Regulations and Bills related to epilepsy have been proposed in several regions. Epilepsy has been officially adopted as a theme to be considered in elementary education by the Ministry of Education. Currently, a National Epilepsy Programme, endorsed by the main Brazilian non-governmental organizations in the field of epilepsy, is under review at the Ministry of Health. We hope that this will benefit some of the many people with epilepsy in the country and will eventually bring epilepsy out of the shadows in Brazil

High-pressure study of the non-Fermi liquid material U_2Pt_2In

The effect of hydrostatic pressure (p<= 1.8 GPa) on the non-Fermi liquid state of U_2Pt_2In is investigated by electrical resistivity measurements in the temperature interval 0.3-300 K. The experiments were carried out on single-crystals with the current along (I||c) and perpendicular (I||a) to the tetragonal axis. The pressure effect is strongly current-direction dependent. For I||a we observe a rapid recovery of the Fermi-liquid T^2-term with pressure. The low-temperature resistivity can be analysed satisfactorily within the magnetotransport theory of Rosch, which provides strong evidence for the location of U_2Pt_2In at an antiferromagnetic quantum critical point. For I||c the resistivity increases under pressure, indicating the enhancement of an additional scattering mechanism. In addition, we have measured the pressure dependence of the antiferromagnetic ordering temperature (T_N= 37.6 K) of the related compound U_2Pd_2In. A simple Doniach-type diagram for U_2Pt_2In and U_2Pd_2In under pressure is presented.Comment: 21 pages (including 5 figures); pdf forma