Convexity of the effective action from functional flows

We show that convexity of the effective action follows from its functional flow equation. Our analysis is based on a new, spectral representation. The results are relevant for the study of physical instabilities. We also derive constraints for convexity-preserving regulators within general truncation schemes including proper-time flows, and bounds for infrared anomalous dimensions of propagators.Comment: 4 pages, 3 figure

Effect of the nearby levels on the resonance fluorescence spectrum of the atom-field interaction

We study the resonance fluorescence in the Jaynes-Cummings model when nearby levels are taking into account. We show that the Stark shift produced by such levels generates a displacement of the peaks of the resonance fluorescence due to an induced effective detuning and also induces an asymmetry. Specific results are presented assuming a coherent and a thermal fields

Delayed Scattering of Solitary Waves from Interfaces in a Granular Container

In granular media, the characterization of the behavior of solitary waves around interfaces is of importance in order to look for more applications of these systems. We study the behavior of solitary waves at both interfaces of a symmetric granular container, a class of systems that has received recent attention because it posses the feature of energy trapping. Hertzian contact is assumed. We have found that the scattering process is elastic at one interface, while at the other interface it is observed that the transmitted solitary wave has stopped its movement during a time that gets longer when the ratio between masses at the interfaces increases. The origin of this effect can be traced back to the phenomenon of gaps opening, recently observed experimentally.Comment: To appear in Physical Review E, vol 7

Scattering of solitary waves in granular media

A detailed numerical study of the scattering of solitary waves by a barrier, in a granular media with Hertzian contact, shows the existence of secondary multipulse structures generated at the interface of two "sonic vacua", which have a similar structure as the one previously found by Nesterenko and coworkers.Comment: 4 pages, 9 figures (fig 5, replaced). Submitted to PR

Extended analytical study of the free-wing/free-trimmer concept

The free wing/free trimmer concept was analytically studied in order to: (1) compare the fore and aft trimmer configurations on the basis of equal lift capability, rather than equal area; (2) assess the influence of tip mounted aft trimmers, both free and fixed, on the lateral directional modes and turbulence responses; (3) examine the feasibility of using differential tip mounted trimmer deflection for lateral control; (4) determine the effects of independent fuselage attitude on the lateral directional behavior; and (5) estimate the influence of wing sweep on dynamic behavior and structural weight. Results indicate that the forward trimmer concept is feasible with the reduced size examined, but it remains inferior to the aft trimmer in every respect except structural weight. Differential motion of the aft trimmer is found to provide powerful lateral control; while the effect of fuselage deck angle is a reduction of the dutch roll damping ratio for nose-down attitudes

Model for Dissipative Highly Nonlinear Waves in Dry Granular Systems

A model is presented for the characterization of dissipative effects on highly nonlinear waves in one-dimensional dry granular media. The model includes three terms: Hertzian, viscoelastic, and a term proportional to the square of the relative velocity of particles. The model outcomes are confronted with different experiments where the granular system is subject to several constraints for different materials. Excellent qualitative and quantitative agreement between theory and experiments is found.Comment: Link to the Journal: http://prl.aps.org/abstract/PRL/v104/i11/e11800

Procesos submarinos de ruptura en el fondo del fiordo Aysén, Norpatagonia, Chile

The present work deals with the relationship between the dislocated sedimentary structures of fjord sub-bottom and the possible sequence of failures in the Aysén Fjordland. The longitudinal profile of the fjord was obtained by means of a 3.5 kHz sub-bottom profiler record, obtained on board of the Vidal Gormaz research vessel. The observations were principally carried out in the ponding esplanade located in the zone of seismic cluster below the fjord. Here, the deformations of the visible sub-bottom affect all the thickness of sediments. There are different styles of deformation of sediments, with greater breakup in the older than in most recent layers. Its 14 C and 210 Pb age extends since the Termination I (Last Glaciation) until the Upper Holocene. Between 1922 and 1995 the earthquake of 1927 happened, giving an inter-seismic period of 80 years until 2007. This earthquake affected with smaller deformation up to the most recent layers judging by its 210Pb age. A sub-bottom record post 2007 earthquake indicates disruptions of the tectonic structures recorded in1995. Therefore: a) the sub-superficial layers of ages between the Holocene and the Termination I can have been deformed also by earthquakes previous to 1927; b) these processes must be recurrent, sleeping, with renewed unbalances; c) its type of frequency must be episodic, oscillating between low (100 to 1000 years) and middle (0 to 100 years); d) its way of activity is by rupture; and e) the known frequency is between ancient-historical and recent historical (1 to 200 years BP or more).    Se estudia la relación entre estructuras sedimentarias dislocadas de sub-fondo y procesos de ruptura en el fiordo Aysén. El perfil longitudinal de éste fue obtenido mediante registros de un perfilador de subfondo a 3.5 kHz obtenidos a bordo del buque de investigación Vidal Gormaz. Las observaciones fueron hechas principalmente en la explanada de represamiento localizada en la zona de enjambre sísmico del fiordo. Aquí, las deformaciones del sub-fondo visible afectan todo el espesor de sedimentos. Hay diferentes estilos de deformación de sedimentos, con mayor ruptura en las capas más antiguas que en las más recientes. Su edad C14 y Pb210 se extiende desde la Terminación I (Última Glaciación) hasta el Holoceno Superior. Entre 1922 y 1995 sucedió el sismo de 1927, dando un período inter-sísmico de 80 años hasta 2007. Este sismo afectó con menor deformación a las capas más recientes según su edad Pb210 . Un registro post sismo 2007 indica rupturas en las estructuras tectónicas registradas en 1995. Por lo tanto: a) las capas sub-superficiales de edades entre el Holoceno y la Terminación I pueden haber sido deformadas también por sismos anteriores a 1927; b) estos procesos deben ser recurrentes, durmientes, con desbalances renovados; c) su tipo de frecuencia debe ser episódico, oscilando entre bajo (100 a 1000 años) y medio (0 a 100 años); d) su tipo de actividad es por ruptura; y e) la frecuencia conocida está entre histórica antigua e histórica reciente (1 a 200 años AP o más).