Melting of scalar mesons and black-hole quasinormal modes in a holographic QCD model

A holographic model for QCD is employed to investigate the effects of the gluon condensate on the spectrum and melting of scalar mesons. We find the evolution of the free energy density with the temperature, and the result shows that the temperature of the confinement/deconfinement transition is sensitive to the gluon-condensate parameter. The spectral functions (SPFs) are also obtained and show a series of peaks in the low-temperature regime, indicating the presence of quasiparticle states associated to the mesons, while the number of peaks decreases with the increment of the temperature, characterizing the quasiparticle melting. In the dual gravitational description, the scalar mesons are identified with the black-hole quasinormal modes (QNMs). We obtain the spectrum of QNMs and the dispersion relations corresponding to the scalar-field perturbations of the gravitational background, and find their dependence with the gluon-condensate parameter.Comment: 30 pages, 12 figures, 5 table

Distribución geográfica de prevalencias regionales de bajo peso al nacer en Perú: Geographic regional distribution of prevalence of low birth weight in Peru

Low birth weight (LBW) continuous to be a global public health problem and it is an important health indicator that identifies the social, economic, and environmental background of the newborn and his family, determined when the birth weight is less than 2500 grams. In Peru, this indicator is evaluated annually through the Encuesta Demográfica y de Salud Familiar.(ENDES). The Ministry of Health of Peru (MINSA) and the Registro Nacional de Identidad y Estado Civil (RENIEC) developed and began the implementation in 2012 of the Certificado de Nacido Vivo en Línea (CNV). This system allows the registration of newborns and generates a real-time birth certificate, also records information such as gender, weight, height, characteristics of gestation and childbirth, among other nominal health variables, this system is free of charge and use by the public and private Health Care Institutions (IPRESS).El Bajo Peso al Nacer (BPN) sigue siendo un problema de salud pública a nivel mundial, es un indicadorimportante de salud que identifica el entorno social, económico y ambiental del recién nacido y sufamilia, determinado cuando el peso al nacer es menor de 2500 gramos. En el Perú, este indicadorse evalúa de forma anual a través de la Encuesta Demográfica y de Salud Familiar (ENDES). El Ministeriode Salud (MINSA) y el Registro Nacional de Identidad y Estado Civil (RENIEC) desarrollaron e iniciaronla implementación en el 2012 del Registro del Certificado de Nacido Vivo en Línea (CNV) este sistemapermite registrar a los recién nacidos y generar en tiempo real el certificado de nacimiento, tambiénpermite registrar datos como sexo, peso, talla, características de la gestación y el parto, entre otrasvariables de salud de manera nominal, este sistema es gratuito y de uso por las Instituciones Prestadorasde Servicios de Salud (IPRESS) públicas y privados del país

Vector meson quasinormal modes in a finite-temperature AdS/QCD model

We study the spectrum of vector mesons in a finite temperature plasma. The plasma is holographically described by a black hole AdS/QCD model. We compute the boundary retarded Green's function using AdS/CFT prescriptions. The corresponding thermal spectral functions show quasiparticle peaks at low temperatures. Then we calculate the quasinormal modes of vector mesons in the soft-wall black hole geometry and analyse their temperature and momentum dependences.Comment: 27 pages, 9 figure

Nonlinear transport and oscillating magnetoresistance in double quantum wells

We study the evolution of low-temperature magnetoresistance in double quantum wells in the region below 1 Tesla as the applied current density increases. A flip of the magneto-intersubband oscillation peaks, which occurs as a result of the current-induced inversion of the quantum component of resistivity, is observed. We also see splitting of these peaks as another manifestation of nonlinear behavior, specific for the two-subband electron systems. The experimental results are quantitatively explained by the theory based on the kinetic equation for the isotropic non-equilibrium part of electron distribution function. The inelastic scattering time is determined from the dependence of the inversion magnetic field on the current.Comment: 20 pages, 10 figure