Multiple-time correlation functions for non-Markovian interaction: Beyond the Quantum Regression Theorem

Multiple time correlation functions are found in the dynamical description of different phenomena. They encode and describe the fluctuations of the dynamical variables of a system. In this paper we formulate a theory of non-Markovian multiple-time correlation functions (MTCF) for a wide class of systems. We derive the dynamical equation of the {\it reduced propagator}, an object that evolve state vectors of the system conditioned to the dynamics of its environment, which is not necessarily at the vacuum state at the initial time. Such reduced propagator is the essential piece to obtain multiple-time correlation functions. An average over the different environmental histories of the reduced propagator permits us to obtain the evolution equations of the multiple-time correlation functions. We also study the evolution of MTCF within the weak coupling limit and it is shown that the multiple-time correlation function of some observables satisfy the Quantum Regression Theorem (QRT), whereas other correlations do not. We set the conditions under which the correlations satisfy the QRT. We illustrate the theory in two different cases; first, solving an exact model for which the MTCF are explicitly given, and second, presenting the results of a numerical integration for a system coupled with a dissipative environment through a non-diagonal interaction.Comment: Submitted (04 Jul 04

Non-Equilibrium Large N Yukawa Dynamics: marching through the Landau pole

The non-equilibrium dynamics of a Yukawa theory with N fermions coupled to a scalar field is studied in the large N limit with the goal of comparing the dynamics predicted from the renormalization group improved effective potential to that obtained including the fermionic backreaction. The effective potential is of the Coleman-Weinberg type. Its renormalization group improvement is unbounded from below and features a Landau pole. When viewed self-consistently, the initial time singularity does not arise. The different regimes of the dynamics of the fully renormalized theory are studied both analytically and numerically. Despite the existence of a Landau pole in the model, the dynamics of the mean field is smooth as it passes the location of the pole. This is a consequence of a remarkable cancellation between the effective potential and the dynamical chiral condensate. The asymptotic evolution is effectively described by a quartic upright effective potential. In all regimes, profuse particle production results in the formation of a dense fermionic plasma with occupation numbers nearly saturated up to a scale of the order of the mean field. This can be interpreted as a chemical potential. We discuss the implications of these results for cosmological preheating.Comment: 36 pages, 14 figures, LaTeX, submitted to Physical Review

Modelado y Análisis de técnicas de acceso basadas en geolocalización para V2V

In this work, two geolocation-based access (GLOC) techniques for vehicular communications are presented and analyzed. These techniques, named Single-Lane Partition (SLP) and Multiple-Lane Partition (MLP) differ on the allocation of transmission resources between different lanes of the road. To assess the benefits of both approaches it is devised a realistic system model that considers the random nature of vehicle locations by means of a Poisson Point Process (PPP), the propagation losses, fast fading, and inter-vehicle interference. Two main types of messages in vehicular communications are considered: Cooperative Awareness Messages (CAM) and Decentralized Environmental Notification Messages (DENM). Simulation results lead to important insight about the behavior of the considered techniques in terms of the Signal to Interference-plus-Noise Ratio (SINR) distribution, i.e., capture probability, the binary rate and the energy efficiency. Results show that MLP performs better at the expense of a greater waste of resources.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Quantum Adiabatic Markovian Master Equations

We develop from first principles Markovian master equations suited for studying the time evolution of a system evolving adiabatically while coupled weakly to a thermal bath. We derive two sets of equations in the adiabatic limit, one using the rotating wave (secular) approximation that results in a master equation in Lindblad form, the other without the rotating wave approximation but not in Lindblad form. The two equations make markedly different predictions depending on whether or not the Lamb shift is included. Our analysis keeps track of the various time- and energy-scales associated with the various approximations we make, and thus allows for a systematic inclusion of higher order corrections, in particular beyond the adiabatic limit. We use our formalism to study the evolution of an Ising spin chain in a transverse field and coupled to a thermal bosonic bath, for which we identify four distinct evolution phases. While we do not expect this to be a generic feature, in one of these phases dissipation acts to increase the fidelity of the system state relative to the adiabatic ground state.Comment: 31 pages, 9 figures. v2: Generalized Markov approximation bound. Included a section on thermal equilibration. v3: Added text that appears in NJP version. Generalized Lindblad ME to include degenerate subspaces. v3. Corrections made to Appendix E and F. We thank Kabuki Takada and Hidetoshi Nishimori for pointing out the errors. v4: Corrected a typo in Eqt. B

Student mentoring program at the Faculty of Pharmacy, University of Seville (2006/07 - present): SWOT analysis carried out by mentor students

El “Programa de Alumnos Tutores” (LCC, Facultad de Farmacia US) se viene realizando ininterrumpidamente desde 2006/07 hasta la actualidad. Propósito: tutela de alumnos de nuevo ingreso por parte de alumnos de cursos superiores (AATT) bajo la supervisión de Profesores Tutores. Pretende generar una actitud responsable en los AATT y favorecerles el desarrollo de habilidades sociales. El objetivo de este trabajo es recoger las opiniones de los AATT (algunos comenzaron en ediciones anteriores y continúan desinteresadamente). Se aborda mediante un análisis DAFO. Conclusión: se han detectado factores estratégicos críticos, para una vez identificados, usarlos y apoyar en ellos la marcha del “Programa de Alumnos Tutores”, consolidando las fortalezas, minimizando las debilidades, aprovechando las ventajas de las oportunidades, y eliminando o reduciendo las amenazas.The "Student Mentor Program" (Faculty of Pharmacy, US) has been running since 2006/07 – to present. Purpose: to mentor new students by senior students (Mentor Students) under the supervision of mentor professors. It aims to generate a responsible attitude in students and tutors to encourage the development of social skills. Objective: To collect the views of mentor students (some started in previous years and continue to selflessly), through a SWOT analysis. Conclusion: it has been found critical strategic factors. It intends to use these factors for strengthening the "Student Mentor Program"

Clash of Titans: The Impact of Cluster Mergers in the Galaxy Cluster Red Sequence

Merging of galaxy clusters are some of the most energetic events in the Universe, and they provide a unique environment to study galaxy evolution. We use a sample of 84 merging and relaxed SPT galaxy clusters candidates, observed with the Dark Energy Camera in the $0.11<z<0.88$ redshift range, to build colour-magnitude diagrams to characterize the impact of cluster mergers on the galaxy population. We divided the sample between relaxed and disturbed, and in two redshifts bin at $z = 0.55$. When comparing the high-z to low-z clusters we find the high-z sample is richer in blue galaxies, independently of the cluster dynamical state. In the high-z bin we find that disturbed clusters exhibit a larger scatter in the Red Sequence, with wider distribution and an excess of bluer galaxies compared to relaxed clusters, while in the low-z bin we find a complete agreement between the relaxed and disturbed clusters. Our results support the scenario in which massive cluster halos at $z<0.55$ galaxies are quenched as satellites of another structure, i.e. outside the cluster, while at $z \geq 0.55$ the quenching is dominated by in-situ processes.Comment: 9 pages, 5 figures, paper accepted in MNRA

Total or partial replacement of fishmeal with soybean meal in the diet of the Pacific fat sleeper Dormitator latifrons juveniles

Groups of Dormitator latifrons in triplicate (4.1 ± 2.0 g and 6.2 ± 1.0 cm) were fed experimental diets containing four levels of substitution of fishmeal (FM) by soybean meal (SM) (0, 40, 70, and 100%, respectively). The diets were formulated to be isoproteic (35% crude protein) and isolipidic (8.0% crude lipids). The effect of each treatment on growth was evaluated and its implications on the cost of feeding. After 60 days of feeding, there were no significant differences in the fish's proximate composition (P < 0.05). There were no significant differences between the diets (P < 0.05) in the evaluated biological indices: total growth increase (TGI), specific growth rate (SGR), thermal growth coefficient (TGC), and survival (%). Feeding costs decreased significantly as the proportion of soybean meal in the diet increased. The results indicated that substituting FM by up to 100% of SM can promote adequate growth in D. latifrons without affecting body composition and survival while also reducing operative costs during the fattening process.Fil: Badillo Zapata, Daniel. Universidad de Guadalajara; MéxicoFil: Musin, Gabriela Eliana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Palma Cancino, David J.. Universidad de Guadalajara; MéxicoFil: Guerrero Galván, Saúl R.. Universidad de Guadalajara; MéxicoFil: Chong Carrillo, Olimpia. Universidad de Guadalajara; MéxicoFil: Vega Villasante, Fernando. Universidad de Guadalajara; Méxic

Study of the mechanical behavior of asphalt mixtures using fractional rheology to model their viscoelasticity

This study focuses on the mechanical behavior of asphalt mixtures composed of aggregate particles attached with an asphalt binder. Asphalt mixtures are viscoelastic composite materials widely used in the construction of pavement layers. The modelling of such materials is currently done using the Burgers model. However, this model is limited when explaining some of the viscoelastic phenomena of an asphalt mixture, mainly because the Burgers model was developed for a single material with a dual nature. This work presents a new approach that provides a more appropriate framework for studying asphalt mixtures. The model assumes an aggregate particle enclosed by an asphalt material. Viscoelastic equations were developed using derivatives of fractional order. Then, the creep, recovery, and relaxation phenomena in an asphalt mixture were analyzed using the new model. Unlike the Burgers model, the new model can predict the elastic jump observed at the beginning of the creep modulus. Thus, the new model seems to describe better those practical cases of asphalt mixtures used in the construction of pavement layers. The new model can be used to modify the properties of the binder for designing optimized and more resistant asphalt mixtures

Mapeo de procesos dentro del área de programas del Organismo de Nutrición Infantil

El PAP es una experiencia de aprendizaje y de contribución social integrada por estudiantes, profesores, actores sociales y responsables de las organizaciones, que de manera colaborativa construir sus conocimientos para dar respuestas a problemáticas de un contexto específico y en un tiempo delimitado. Por tanto, la experiencia PAP supone un proceso en lógica de proyecto, así como de un estilo de trabajo participativo y recíproco entre los involucrados. La organización donde se trabajará el proyecto PAP es en el Organismo de Nutrición Infantil, con el que se tuvo el primer acercamiento con la organización el miércoles 9 de febrero. Durante la reunión que se tuvo se definió el contexto actual de la organización y se presentaron los distintos proyectos a desarrollar, dependiendo de la carrera y los intereses de los miembros del equipo. Este documento abarcará el proyecto realizado por los estudiantes de ingeniería industrial, el cual consta del mapeo y documentación de procesos de un área de importancia especificada por el ONI.ITESO, A.C