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Tunja, Colombia

La Universidad Pedagógica y Tecnológica de Colombia best known as "La UPTC," is a Colombian public university located primarily in Tunja and it maintains presence in 7 Colombian departments. It is considered to be one of the most important and prestigious universities of the country due to their academic level.It has a headquartera, three sectional branches, six sites for extension programs and 21 regional centers for distance learning in which there are 11 faculties, 52 undergraduate academic programs, 15 undergraduate academic distance programs and 23 postgraduate programs. It is an educational, scientific and technological university, currently ranked number 7 among the best 64 universities in Colombia according to a study by Research Sapiens Group research sapiens that built a ranking, which was titled "U-Sapiens Ranking Colombia" where are cataloged 64 universities of the country. Wikipedia.

Reyes Gomez F.,Pedagogical and Technological University of Colombia | Mejia-Salazar J.R.,Federal University of Alagoas
Optics Letters | Year: 2015

We show the existence of a defect mode within the plasmonpolariton gap in 1D defective photonic superlattices, composed by alternating layers of conventional dielectric (A) and negative refractive (B) material slabs with a dielectric defective layer (D), which, in the nonlinear regime, can be tuned by means of the incident field intensity. Also, we have shown that the self-induced transparency phenomena can be only observed when gap-soliton modes, coupled through the defective layer, are excited in both mirror systems around the defective slab. © 2015 Optical Society of America.

Gallego D.,Pedagogical and Technological University of Colombia
Nuclear and Particle Physics Proceedings | Year: 2015

After reviewing several mechanisms proposed to get a dS/Minkowski vacuum in moduli stabilization scenarios of type-IIB superstring orientifold compactifications we propose a criterium for characterizing those that may effectively lead to a positive small cosmological constant. We suggest that the variation in the expectation value of a good uplifting term, due to the shift in the minimum of the potential after uplifting, is much smaller than the original cosmological constant. This is studied with some detail in Large volume scenarios where the dependency on the volume direction is rather generic and easy to spot. Here we find that an uplifting term in the potential, with generic form Vup~1/Vγ, should be restricted to the one satisfying γ. ≪. 12. Such a bound might explain why in models previously studied no uplifting has been achieved, and gives motivations to study a novel proposal of dilaton dependent uplifting mechanism for which no numerical studies has been performed before. We find that in this case it is actually possible to get a dS vacuum, but still leave open the question of a more precise discrimination feature the good uplifting mechanisms should satisfy. © 2015 Elsevier B.V.

Gallego D.,Pedagogical and Technological University of Colombia
International Journal of Modern Physics A | Year: 2014

We revisit the integration of fields in N= 1 Supergravity with the requirement that the effective theory has a reliable two-derivative supersymmetric description. In particular, we study, in a supersymmetric manifest way, the situation where the fields that are mapped out have masses comparable to the Supersymmetry breaking scale and masses of the remaining fields. We find that as long as one stands in regions of the field configuration space where the analytic continuation to superspace of the F-flatness conditions be reliable equations of motion for the fields that are being mapped out, and provided their solutions are stable regardless the dynamics of the remaining fields, such a two-derivative description is a reliable truncation of the full effective theory. The study is mainly focused to models with two chiral sectors, H and L, described by a Kähler invariant function with schematic dependencies of the form G = GH(H,H¯)+GL(L,L¯), which leads to a nearly decoupled theory that allows the previous requirements to be easily satisfied in a consistent way. Interestingly, enough for the matters of our study, this kind of models present a scenario that is as safe as the one presented in sequestered models. It is also possible to allow gauge symmetries as long as these appear also factorized in hidden and visible sectors. Then, the integration of the hidden vector superfields is compulsory and proceeds reliably through the D-flatness condition analytically continued to superspace. © 2015 World Scientific Publishing Company.

Camarchia V.,Polytechnic University of Turin | Fang J.,Polytechnic University of Turin | Moreno Rubio J.,Pedagogical and Technological University of Colombia | Pirola M.,Polytechnic University of Turin | Quaglia R.,Polytechnic University of Turin
IEEE Microwave and Wireless Components Letters | Year: 2013

Design and characterization of a 7 GHz MMIC GaN Doherty Power Amplifier on TriQuint technology are presented. To the best of the authors' knowledge, the present circuit, suitable for C-band point-to-point backhaul applications, represents the first example of a working MMIC GaN Doherty. Large signal measurements, averaged over 16 MMICs, exhibited power gain of 10 dB, saturated output power in excess of 37 dBm (3 dB gain compression), together with drain efficiency of 47%, at 7 dB of output back-off, and higher than 35% in a 350 MHz band. Two-tone characterization has shown a carrier to 3rd order intermodulation ratio higher than 25 dB in the Doherty region. © 2001-2012 IEEE.

Chiquillo E.,Pedagogical and Technological University of Colombia
Journal of Physics A: Mathematical and Theoretical | Year: 2015

We investigate the one-dimensional (1D) and two-dimensional (2D) reduction of a quantum field theory starting from the three-dimensional (3D) many-body Hamiltonian of interacting bosons with spin-orbit (SO) and Rabi couplings. We obtain the effective time-dependent 1D and 2D nonpolynomial Heisenberg equations for both the repulsive and attractive signs of the inter-atomic interaction. Our findings show that in the case in which the many-body state coincides with the Glauber coherent state, the 1D and 2D Heisenberg equations become 1D and 2D nonpolynomial Schrödinger equations (NPSEs). These models were derived in a mean-field approximation from 3D Gross-Pitaevskii equation (GPE), describing a Bose-Einstein condensate (BEC) with SO and Rabi couplings. In the present work self-repulsive and self-attractive localized solutions of the 1D NPSE and the 1D GPE are obtained in a numerical form. The combined action of SO and Rabi couplings produces conspicuous sidelobes on the density profile, for both signs of the interaction. In the case of the attractive nonlinearity, an essential result is the possibility of getting an unstable condensate by the increasing of SO coupling. © 2015 IOP Publishing Ltd.

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