Now showing items 23-42 of 62

    • Exact solution of an ekpyrotic fluid and a primordial magnetic field in an anisotropic cosmological space-time of Petrov D 

      Alvarado Marín, Rodrigo Eduardo (2017)
      This document obtained and analyzed an exact solution of an ekpyrotic fluid (P = 5/3 µ) and a primordial magnetic field, so that the latter does not induce currents or electric fields. It is determined that the main role, ...
    • Exact Solutions of a Chaplygin Gas in an Anisotropic Space-Time of Petrov D 

      Alvarado Marín, Rodrigo Eduardo (2017)
      This document obtains two exact solutions to the anisotropic spacetime of Petrov D by using the model of a perfect fluid. These solutions represent a scenario of a universe in which the pressure P and the energetic density ...
    • Fundamentals of silicene 

      Willatzen, Morten; Lew Yan Voon, Lok Chong; Guzmán Verri, Gian Giacomo (2017-08-02)
      Silicene is a single atomic layer of silicon (Si) much like graphene, the first example of an elemental twodimensional (2D) nanomaterial whose study led to the 2010 Nobel Prize in Physics. Until 2010 or so, the only known ...
    • GeV Emission in the Region of the Supernova Remnant G51.26+0.11 

      Araya Arguedas, Miguel (2021-11-02)
      The supernova remnant G51.26+0.11 was recently discovered and little is known about its properties and environment. Using data from the Fermi Large Area Telescope we study the GeV emission seen in the direction of G51.26+0.11 ...
    • (Hydro)climatological studies of climate change and variability in Central America 

      Hidalgo León, Hugo G. (2018-06-26)
      This is the presentation of Hugo Hidalgo at the CORDEX Central America and South America Training Workshop on Downscaling Techniques, in La Paz, Bolivia, June 25 to 27, 2018.
    • Informe Final: Articulación de un sistema de identificación de locutor con fines forenses 

      Ortega Rodríguez, Manuel (2016-02-29)
      La investigación tiene que ver con la identificación automatizada de locutor (Voice ID) con fines forenses (lo cual convierte a este proyecto en un trabajo de fuerte aplicación en temas de sociedad). El objetivo general ...
    • Interaction of a quantum field with a rotating heat bath 

      Alicki, Robert; Jenkins Villalobos, Alejandro (2018-08-01)
      The linear coupling of a rotating heat bath to a quantum field is studied in the framework of the Markovian master equation for the field's non-unitary time evolution. The bath's rotation induces population inversion for ...
    • Irreversibility in an ideal fluid 

      Jenkins Villalobos, Alejandro (2014-10)
      When a real fluid is expelled quickly from a tube, it forms a jet separated from the surrounding fluid by a thin, turbulent layer. On the other hand, when the same fluid is sucked into the tube, it comes in from all ...
    • Irreversibility of mechanical and hydrodynamic instabilities 

      Díaz Marín, Carlos D.; Jenkins Villalobos, Alejandro (2017-12-01)
      The literature on dynamical systems has, for the most part, considered self-oscillators (i.e., systems capable of generating and maintaining a periodic motion at the expense of an external energy source with no corresponding ...
    • Landau theory and giant room-temperature barocaloric effect 

      Corrales Salazar, A.; Brierley, Richard T.; Littlewood, Peter B.; Guzmán Verri, Gian Giacomo (2017-10-17)
      The structural phase transitions of MF3 (M = Al, Cr, V, Fe, Ti, Sc) metal trifluorides are studied within a simple Landau theory consisting of tilts of rigid MF6 octahedra associated with soft antiferrodistortive optic ...
    • Large isotropic negative thermal expansion above a structural quantum phase transition 

      Handunkanda, Sahan U.; Curry, Erin B.; Voronov, Vladimir; Said, Ayman H.; Guzmán Verri, Gian Giacomo; Brierley, Richard T.; Littlewood, Peter B.; Hancock, Jason N. (2015-10-01)
      Perovskite structured materials contain myriad tunable ordered phases of electronic and magnetic origin with proven technological importance and strong promise for a variety of energy solutions. An always-contributing ...
    • Leaking elastic capacitor as model for active matter 

      Alicki, Robert; Gelbwaser Klimovsky, David; Jenkins Villalobos, Alejandro (2021-05-24)
      We introduce the “leaking elastic capacitor” (LEC) model, a nonconservative dynamical system that combines simple electrical and mechanical degrees of freedom. We show that an LEC connected to an external voltage source ...
    • Modelado del espacio-tiempo en el interior de una estrella de neutrones en rotación con un cuadrupolo agregado de forma perturbativa 

      Morales Montenegro, Julio César (2021-11-07)
      The potentials and multipolar parameters for a neutron star internal space-time model are calculated in a perturbative series using the angular velocity as perturbation parameter. Twelve equations of state are considered, ...
    • Negative Thermal Expansion in Open Perovskites near the Precipice of Structural Stability 

      Occhialini, Connor A.; Guzmán Verri, Gian Giacomo; Handunkanda, Sahan U.; Hancock, Jason N. (2018)
      Negative thermal expansion (NTE) describes the anomalous propensity of materials to shrink when heated. Since its discovery, the NTE effect has been found in a wide variety of materials with an array of magnetic, electronic ...
    • Negative thermal expansion near two structural quantum phase transitions Connor 

      Guzmán Verri, Gian Giacomo; Hancock, Jason N. (2017-12-18)
      Recent experimental work has revealed that the unusually strong, isotropic structural negative thermal expansion in cubic perovskite ionic insulator ScF3 occurs in excited states above a ground state tuned very near a ...
    • Observed Changes (1970-1999) in Extreme Hydroclimatic Events in Central America 

      Hidalgo León, Hugo G.; Alfaro Martínez, Eric J. (2018-04-20)
      Previous studies have shown that most of Central America has been experiencing warming trends during the last 30-50 years, while precipitation annual totals have not changed much. Warming alone can exacerbate the effects ...
    • Optical component 

      Padilla Víquez, Gerardo José (2010-02-15)
      El invento trata de un componente óptico, que comprende un primer reflector esférico y un segundo reflector esférico, el cual está colocado para reflejar un rayo de luz varias veces entre el primer reflector y el segundo ...
    • Phototransport Properties of a-SiC:H Alloys 

      Balberg, I.; Nery, Guillermo; Ramírez Porras, Arturo; Resto, O.; Weisz, S. Z.; Lubianiker, Y. (1995)
      We report a study of the mobility-lifetime products of the two charge carriers in a-SiC:H alloys. The measurements were carried out as a function of the carbon concentration and the temperature. An analysis, relying on the ...
    • Pressure dependence of ferroelectric quantum critical fluctuation 

      Coak, Matthew J.; Haines, Charles Robert Sebastian; Liu, Cheng; Guzmán Verri, Gian Giacomo; Saxena, Siddharth S. (2019-12-13)
      Phase transitions to a long-range-ordered state driven by a softened phonon mode are ubiquitous across condensed matter physics, but the evolution of such a mode as the system is tuned to or from the transition has never ...
    • Quantum Ferroelectric Instabilities in Superconducting SrTiO3 

      Arce Gamboa, José Rafael; Guzmán Verri, Gian Giacomo (2018)
      We examine the effects of strain and cation substitution on the superconducting phase of polar semiconductors near a ferroelectric quantum phase transition with a model that combines a strong coupling theory of ...