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Search Results: 1 - 10 of 9133 matches for " Ortiz Segura Gerardo "
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Classification, Identification, and Manipulation of Relevant Factors for Adaptation and Behavioural Adjustment from a Psychological Point of View  [PDF]
Gerardo Ortiz
Psychology (PSYCH) , 2014, DOI: 10.4236/psych.2014.513162
Abstract: Generally, the study of animal welfare is based on the identification and promotion of speciestypical behaviors of the individual or target group. The adjustment to new conditions (i.e. captivity) is easier for some species, while for others it may be very difficult or even impossible. The adjustment to captive conditions is a basic element for the development of conservation strategies (i.e. translocation, introduction, and reintroduction) and can be measured by different variables related to an animal’s psychological well-being. From a psychological point of view, we assume that organisms can adjust their behavior in correspondence to changes in their environment, adjustment that is enabled by an ecological contact medium (e.g. Ribes, 2007; Ribes & Perez-Almonacid, 2011). Under this assumption, we propose a methodology that allows the classification, identification and manipulation of relevant factors for an individual’s adjustment to different conditions (i.e. freedom and captivity) and a more rational handling of organisms and their specific life condition. The main elements of this methodology are: 1) adaptive and survival circumstances; 2) description of ecological milieu; 3) interactive processes (i.e. intra-individual, inter-individual, and inter-individual dependence); and 4) interaction-situation relationship.
Monitoreo bacteriológico en el aire interior de un edificio
Rivera Tapia José Antonio, Sánchez Hernández José Antonio, Ortiz Segura Gerardo, Barahona Argueta Carlos.
Acta Cientifica Estudiantil , 2009,
Abstract: El estudio de la calidad del aire en interiores es un problema ambiental, de tal forma se ha planteado que la contaminación en interiores implica efectos negativos en la salud. La presencia de agentes biológicos en el aire de interiores, puede contribuir al síndrome del edificio enfermo, condicionando padecimientos en vías respiratorias, tracto digestivo, ojos y en la piel de los ocupantes. El objetivo del presente trabajo fue monitorear la presencia de bacterias en el aire interior en un edificio universitario de tecnología educativa. Para el muestreo por placa expuesta se emplearon medios enriquecidos y selectivos, y para la identificación de los aislamientos se utilizó medio de orientación. El muestreo se realizó por triplicado en diferentes áreas del edificio a una altura de 1.50 metros durante 30 minutos. El muestreo se realizó durante tres meses a las 12:00 horas, los medios de cultivo se incubaron a 37 oC durante 48 horas. Durante los tres meses de muestreo se aislaron un total de 4383 UFC, distribuyéndose en los géneros Proteus (30.5%), Escherichia (11%) y Enterococcus (58.5%). Los datos obtenidos impactan desde el punto de vista social, laboral y de salud pública, ya que se monitoreo la presencia de bacterias en un ambiente intramuros. Y aunque las bacterias asiladas se consideran inocuas, no se debe descartar que otro factor biótico o abiótico puede condicionar su papel como agentes etiológicos en algunos padecimientos propios del humano.
Bond Algebras and Exact Solvability of Hamiltonians: Spin S=1/2 Multilayer Systems and Other Curiosities
Zohar Nussinov,Gerardo Ortiz
Physics , 2008, DOI: 10.1103/PhysRevB.79.214440
Abstract: We introduce an algebraic methodology for designing exactly-solvable Lie model Hamiltonians. The idea consists in looking at the algebra generated by bond operators. We illustrate how this method can be applied to solve numerous problems of current interest in the context of topological quantum order. These include Kitaev's toric code and honeycomb models, a vector exchange model, and a Clifford gamma model on a triangular lattice.
A symmetry principle for Topological Quantum Order
Zohar Nussinov,Gerardo Ortiz
Physics , 2007, DOI: 10.1016/j.aop.2008.11.002
Abstract: We present a unifying framework to study physical systems which exhibit topological quantum order (TQO). The guiding principle behind our approach is that of symmetries and entanglement. We introduce the concept of low-dimensional Gauge-Like Symmetries (GLSs), and the physical conservation laws (including topological terms and fractionalization) which emerge from them. We prove then sufficient conditions for TQO at both zero and finite temperatures. The topological defects which are associated with the restoration of GLSs lead to TQO. Selection rules associated with the GLSs enable us to systematically construct states with TQO; these selection rules do not rely on the existence of a finite gap between the ground states to all other excited states. All currently known examples of TQO display GLSs. We analyze spectral structures and show that Kitaev's toric code model and Wen's plaquette model are equivalent and reduce, by a duality mapping, to an Ising chain. Despite the spectral gap in these systems, the toric operator expectation values may vanish once thermal fluctuations are present. This mapping illustrates that the quantum states themselves in a particular (operator language) representation encode TQO and that the duality mappings, being non-local in the original representation, disentangle the order. We present a general algorithm for the construction of long-range string orders in general systems with entangled ground states.
Adiabatic Perturbation Theory and Geometric Phases for Degenerate Systems
Gustavo Rigolin,Gerardo Ortiz
Physics , 2010, DOI: 10.1103/PhysRevLett.104.170406
Abstract: We introduce an adiabatic perturbation theory for quantum systems with degenerate energy spectra. This perturbative series enables one to rigorously establish conditions for the validity of the adiabatic theorem of quantum mechanics for degenerate systems. The same formalism can be used to find non-adiabatic corrections to the non-Abelian Wilczek-Zee geometric phase. These corrections are relevant to assess the validity of the practical implementation of the concept of fractional exchange statistics. We illustrate the formalism by exactly solving a time-dependent problem and comparing its solution to the perturbative one.
Orbital order driven quantum criticality
Zohar Nussinov,Gerardo Ortiz
Physics , 2008, DOI: 10.1209/0295-5075/84/36005
Abstract: Charge, spin, and orbital degrees of freedom underlie the physics of transition metal compounds. Much work has revealed quantum critical points associated with spin and charge degrees of freedom in many of these systems. Here we illustrate that the simplest models that embody the orbital degrees of freedom - the two- and three-dimensional quantum orbital compass models - exhibit an exact quantum critical behavior on diluted square and cubic lattices (with a doping fraction of 1/4 and 1/2 respectively). This raises the possibility of quantum critical points triggered by the degradation of orbital order upon doping (or applying pressure to) such transition metal systems. We prove the existence of an orbital spin glass in several related systems in which the orbital couplings are made non-uniform. Moreover, a new orbital Larmor precession (i.e., a periodic change in the orbital state) is predicted when uniaxial pressure is applied.
The Adiabatic Theorem for Quantum Systems with Spectral Degeneracy
Gustavo Rigolin,Gerardo Ortiz
Physics , 2011, DOI: 10.1103/PhysRevA.85.062111
Abstract: By stating the adiabatic theorem of quantum mechanics in a clear and rigorous way, we establish a necessary condition and a sufficient condition for its validity, where the latter is obtained employing our recently developed adiabatic perturbation theory. Also, we simplify further the sufficient condition into a useful and simple practical test at the expenses of its mathematical rigor. We present results for the most general case of quantum systems, i.e., those with degenerate energy spectra. These conditions are of upmost importance to assess the validity of practical implementations of non-Abelian braiding and adiabatic quantum computation. To illustrate the degenerate adiabatic approximation, and the necessary and sufficient conditions for its validity, we analyze in depth an exactly solvable time-dependent degenerate problem.
Autocorrelations and Thermal Fragility of Anyonic Loops in Topologically Quantum Ordered Systems
Zohar Nussinov,Gerardo Ortiz
Physics , 2007, DOI: 10.1103/PhysRevB.77.064302
Abstract: Are systems that display Topological Quantum Order (TQO), and have a gap to excitations, hardware fault-tolerant at finite temperatures? We show that in surface code models that display low d-dimensional Gauge-Like Symmetries, such as Kitaev's and its generalizations, the expectation value of topological symmetry operators vanishes at any non-zero temperature, a phenomenon that we coined thermal fragility. The autocorrelation time for the non-local topological quantities in these systems may remain finite even in the thermodynamic limit. We provide explicit expressions for the autocorrelation functions in Kitaev's model. If temperatures far below the gap may be achieved then these autocorrelation times, albeit finite, can be made large. The physical engine behind the loss of correlations at large spatial and/or temporal distance is the proliferation of topological defects at any finite temperature as a result of a dimensional reduction. This raises an important question: How may we best quantify the degree of protection of quantum information in a topologically ordered system at finite temperature?
Degenerate Adiabatic Perturbation Theory: Foundations and Applications
Gustavo Rigolin,Gerardo Ortiz
Physics , 2014, DOI: 10.1103/PhysRevA.90.022104
Abstract: We present details and expand on the framework leading to the recently introduced degenerate adiabatic perturbation theory [Phys. Rev. Lett. 104, 170406 (2010)], and on the formulation of the degenerate adiabatic theorem, along with its necessary and sufficient conditions given in [Phys. Rev. A 85, 062111 (2012)]. We start with the adiabatic approximation for degenerate Hamiltonians that paves the way to a clear and rigorous statement of the associated degenerate adiabatic theorem, where the non-abelian geometric phase (Wilczek-Zee phase) plays a central role to its quantitative formulation. We then describe the degenerate adiabatic perturbation theory, whose zeroth order term is the degenerate adiabatic approximation, in its full generality. The parameter in the perturbative power series expansion of the time-dependent wave function is directly associated to the inverse of the time it takes to drive the system from its initial to its final state. With the aid of the degenerate adiabatic perturbation theory we obtain rigorous necessary and sufficient conditions for the validity of the adiabatic theorem of quantum mechanics. Finally, to illustrate the power and wide scope of the methodology, we apply the framework to a degenerate Hamiltonian, whose closed form time-dependent wave function is derived exactly, and also to other non-exactly-solvable Hamiltonians whose solutions are numerically computed.
Fock Parafermions and Self-Dual Representations of the Braid Group
Emilio Cobanera,Gerardo Ortiz
Physics , 2013, DOI: 10.1103/PhysRevA.89.012328
Abstract: We introduce and describe in second quantization a family of particle species with \(p=2,3,\dots\) exclusion and \(\theta=2\pi/p\) exchange statistics. We call these anyons Fock parafermions, because they are the particles naturally associated to the parafermionic zero-energy modes, potentially realizable in mesoscopic arrays of fractional topological insulators. Their second-quantization description entails the concept of Fock algebra, i.e., a Fock space endowed with a statistical multiplication that captures and logically correlates these anyons' exclusion and exchange statistics. As a consequence normal-ordering continues to be a well-defined operation. Because of its relevance to topological quantum information processing, we also derive families of self-dual representations of the braid group for any $p$, with the Gaussian representation being a special case. The self-dual representations can be realized in terms of local quadratic combinations of either parafermions or Fock parafermions, an important requisite for physical implementation of quantum logic gates.
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