Now showing items 21-40 of 51

    • (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.
    • 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 ...
    • 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 ...
    • Random Electric Field Instabilities of Relaxor Ferroelectrics 

      Guzmán Verri, Gian Giacomo; Arce Gamboa, José Rafael (2017-06-13)
      Relaxor ferroelectrics are complex oxide materials which are rather unique to study the effects of compositional disorder on phase transitions. Here, we study the effects of quenched cubic random electric fields on the ...
    • Relation between Luminescence and Electronic Surface Characteristics in p-type Porous Silicon 

      Weisz, S. Z.; Ramírez Porras, Arturo; Gómez, Manuel; Many, A.; Goldstein, Yehuda; Savir, Esther (1997)
      Measurements of photoluminescence, electronic surface states and effective surface area, at various stages of the anodization process, are presented. The results show a behavior different from that observed on n-type porous Si.
    • Search for gamma-ray emission from star-forming galaxies with Fermi LAT 

      Rojas Bravo, César; Araya Arguedas, Miguel (2016-08)
      Recent studies have found a positive correlation between the star-formation rate of galaxies and their gamma-ray luminosity. Galaxies with a high star-formation rate are expected to produce a large amount of high-energy ...
    • Stochastic approach to the smart quantum confinement model in porous silicon 

      Ramírez Porras, Arturo; Weisz, S. Z. (Surface Science 515 (2002) L509-L513, 2002)
      A model that encompasses two approaches to explain the photoluminescence in p-type porous silicon is proposed. The model considers a stochastic distribution of nanocrystallite sizes within the porous matrix and explain the ...
    • Structure factor of a relaxor ferroelectric 

      Guzmán Verri, Gian Giacomo; Varma, Chandra M. (2015-04-14)
      We study a minimal model for a relaxor ferroelectric including dipolar interactions, and short-range harmonic and anharmonic forces for the critical modes as in the theory of pure ferroelectrics together with quenched ...