Specific Realization Research Articles

Infrared fixed point physics in SO(Nc) and Sp(Nc) gauge theories

We study properties of asymptotically free vectorial gauge theories with gauge groups $G={\rm SO}(N_c)$ and $G={\rm Sp}(N_c)$ and $N_f$ fermions in a representation $R$ of $G$, at an infrared (IR) zero of the beta function, $\alpha_{IR}$, in the non-Abelian Coulomb phase. The fundamental, adjoint, and rank-2 symmetric and antisymmetric tensor fermion representations are considered. We present scheme-independent calculations of the anomalous dimensions of (gauge-invariant) fermion bilinear operators $\gamma_{\bar\psi\psi,IR}$ to $O(\Delta_f^4)$ and of the derivative of the beta function at $\alpha_{IR}$, denoted $\beta'_{IR}$, to $O(\Delta_f^5)$, where $\Delta_f$ is an $N_f$-dependent expansion variable. It is shown that all coefficients in the expansion of $\gamma_{\bar\psi\psi,IR}$ that we calculate are positive for all representations considered, so that to $O(\Delta_f^4)$, $\gamma_{\bar\psi\psi,IR}$ increases monotonically with decreasing $N_f$ in the non-Abelian Coulomb phase. Using this property, we give a new estimate of the lower end of this phase for some specific realizations of these theories.

MYTH AND SYMBOLS IN WOLE SOYINKA'S IDANRE

Poetry and mythology are narrowly associated. In the various civilizations poetry originates in oral form from mythology, acquiring its first written realization in the narrative or epic poem. Although it has distanced itself from its narrative origins, many writers in the Twentieth Century have reaffirmed myth and narrative in poetry. Among them, the Nigerian poet and playwright Wole Soyinka stands out, whose works both in drama and poetry are largely inspired by Yoruba mythology. An example of this is the narrative poem Idanre , which provides an account of the creation myth of Ogun, Yoruba god of iron, culture and creativity, set in modern times. This study is an investigation and discussion of the presence of myth and symbols associated to it in the poem and their specific realization in Yoruba mythology.

Evolution of Greenery in Housing Estates

One of the basic values of multi-family housing estates which were built in the second half of the 20th century was their green areas. It was assumed that open spaces would serve both recreational and health purposes (related to air ventilation or air purification). In Poland, as in other socialist countries, these areas were parameterized and their size was defined in the relevant legislative documents. The principles of location of these sites in the structure of the estate as well as their equipment have changed during the period taken under consideration. Comparative analysis of specific realizations allows for their characterization and evaluation and reference to contemporary views. In the 1940s and 1950s, these areas were designed in the form of small squares and green areas located in the neighbourhood of the streets. In the sixties and seventies there were small residential parks (usually less than 1 ha). In the 1980s, extensive green areas were being developed which, for economic reasons, remained untouched in a functional way. Another decade (1990s) is associated with political and economic changes in Poland. In the case of estate greenery, it resulted in a complete deviation from its implementation. However, green was introduced on the roofs of buildings (including underground garages). Nowadays, the return to the design of large areas of greenery connected with housing development is being re-established. Their main function is recreational and leisure. One of the new tasks assigned to them is the task of gathering precipitation water. As a result of the analyses conducted, the author indicates which of the historical realizations (chosen periods) best meet modern needs and which can be adapted.

Will-Nordtvedt PPN formalism applied to renormalization group extensions of general relativity

Here we apply the full Will-Nordtvedt version of the Parameterized Post-Newtonian (PPN) formalism to a class of General Relativity extensions that are based on nontrivial renormalization group (RG) effects at large scales. We focus on a class of models in which the gravitational coupling constant $G$ is correlated with the Newtonian potential. A previous PPN analysis considered a specific realization of the RG effects, and only within the Eddington-Robertson-Schiff version of the PPN formalism, which is a less complete and robust PPN formulation. Here we find stronger, more precise bounds, and with less assumptions. We also consider the External Potential Effect (EPE), which is an effect that is intrinsic to this framework and depends on the system environment (it has some qualitative similarities to the screening mechanisms of modified gravity theories). We find a single particular RG realization that is not affected by the EPE. Some physical systems have been pointed out as candidates for measuring the possible RG effects in gravity at large scales, for any of them the Solar System bounds need to be considered.

Antimonotonicity, Crisis and Multiple Attractors in a Simple Memristive Circuit

In this work a memristive circuit consisting of a first-order memristive diode bridge is presented. The proposed circuit is the simplest memristive circuit containing the specific circuitry realization of the memristor to be so far presented in the literature. Characterization of the proposed circuit confirms its complex dynamic behavior, which is studied by using well-known numerical tools of nonlinear theory, such as bifurcation diagram, Lyapunov exponents and phase portraits. Various dynamical phenomena concerning chaos theory, such as antimonotonicity, which is observed for the first time in this type of memristive circuits, crisis phenomenon and multiple attractors, have been observed. An electronic circuit to reproduce the proposed memristive circuit was designed, and experiments were conducted to verify the results obtained from the numerical simulations.

Approach to equilibrium of a quantum system and generalization of the Montroll–Shuler equation for vibrational relaxation of a molecular oscillator

The approach to equilibrium of a quantum mechanical system in interaction with a bath is studied from a practical as well as a conceptual point of view. Explicit memory functions are derived for given models of bath couplings. If the system is a harmonic oscillator representing a molecule in interaction with a reservoir, the generalized master equation derived becomes an extension into the coherent domain of the well-known Montroll–Shuler equation for vibrational relaxation and unimolecular dissociation. A generalization of the Bethe–Teller result regarding energy relaxation is found for short times. The theory has obvious applications to relaxation dynamics at ultra-short times as in observations on the femtosecond time scale and to the investigation of quantum coherence at those short times. While vibrational relaxation in chemical physics is a primary target of the study, another system of interest in condensed matter physics, an electron or hole in a lattice subjected to a strong DC electric field that gives rise to well-known Wannier–Stark ladders, is naturally addressed with the theory. Specific system–bath interactions are explored to obtain explicit details of the dynamics. General phenomenological descriptions of the reservoir are considered rather than specific microscopic realizations.

Equalization of multi-Gb/s chip-to-chip interconnects affected by manufacturing tolerances

Electrical chip-to-chip interconnects suffer from considerable intersymbol interference at multi-Gb/s data rates, due to the frequency-dependent attenuation. Hence, reliable communication at high data rates requires equalization, to compensate for the channel response. As these interconnects are prone to manufacturing tolerances, the equalizer must be adjusted to each specific channel realization to perform optimally. We adopt a reduced-complexity equalization scheme where (part of) the equalizer is fixed, by involving the channel statistics into the equalizer derivation. For a 10 cm on-board microstrip interconnect with a 10% tolerance on its parameters, we point out that 2-PAM transmission using a fixed prefilter and an adjustable feedback filter, both with few taps, yields only a moderate bit error rate degradation, compared to the all-adjustable equalizer; at a bit error rate of 10−12, these degradations are about 1.1 dB and 3 dB, when operating at 20 Gb/s and 80 Gb/s, respectively.

Focusing inside Disordered Media with the Generalized Wigner-Smith Operator.

We introduce a wave front shaping protocol for focusing inside disordered media based on a generalization of the established Wigner-Smith time-delay operator. The key ingredient for our approach is the scattering (or transmission) matrix of the medium and its derivative with respect to the position of the target one aims to focus on. A specific experimental realization in the microwave regime is presented showing that the eigenstates of a corresponding operator are sorted by their focusing strength-ranging from strongly focusing on the designated target to completely bypassing it. Our protocol works without optimization or phase conjugation and we expect it to be particularly attractive for optical imaging in disordered media.

Flood risk reduction and flow buffering as ecosystem services – Part 1: Theory on flow persistence, flashiness and base flow

Abstract. Flood damage reflects insufficient adaptation of human presence and activity to location and variability of river flow in a given climate. Flood risk increases when landscapes degrade, counteracted or aggravated by engineering solutions. Efforts to maintain and restore buffering as an ecosystem function may help adaptation to climate change, but this require quantification of effectiveness in their specific social-ecological context. However, the specific role of forests, trees, soil and drainage pathways in flow buffering, given geology, land form and climate, remains controversial. When complementing the scarce heavily instrumented catchments with reliable long-term data, especially in the tropics, there is a need for metrics for data-sparse conditions. We present and discuss a flow persistence metric that relates transmission to river flow of peak rainfall events to the base-flow component of the water balance. The dimensionless flow persistence parameter Fp is defined in a recursive flow model and can be estimated from limited time series of observed daily flow, without requiring knowledge of spatially distributed rainfall upstream. The Fp metric (or its change over time from what appears to be the local norm) matches local knowledge concepts. Inter-annual variation in the Fp metric in sample watersheds correlates with variation in the flashiness index used in existing watershed health monitoring programmes, but the relationship between these metrics varies with context. Inter-annual variation in Fp also correlates with common base-flow indicators, but again in a way that varies between watersheds. Further exploration of the responsiveness of Fp in watersheds with different characteristics to the interaction of land cover and the specific realisation of space–time patterns of rainfall in a limited observation period is needed to evaluate interpretation of Fp as an indicator of anthropogenic changes in watershed conditions.

Spontaneous emergence of catalytic cycles with colloidal spheres

Colloidal particles endowed with specific time-dependent interactions are a promising route for realizing artificial materials that have the properties of living ones. Previous work has demonstrated how this system can give rise to self-replication. Here, we introduce the process of colloidal catalysis, in which clusters of particles catalyze the creation of other clusters through templating reactions. Surprisingly, we find that simple templating rules generically lead to the production of huge numbers of clusters. The templating reactions among this sea of clusters give rise to an exponentially growing catalytic cycle, a specific realization of Dyson's notion of an exponentially growing metabolism. We demonstrate this behavior with a fixed set of interactions between particles chosen to allow a catalysis of a specific six-particle cluster from a specific seven-particle cluster, yet giving rise to the catalytic production of a sea of clusters of sizes between 2 and 11 particles. The fact that an exponentially growing cycle emerges naturally from such a simple scheme demonstrates that the emergence of exponentially growing metabolisms could be simpler than previously imagined.

A neutrino mass-mixing sum rule from SO(10) and neutrinoless double beta decay

Minimal SO(10) grand unified models provide phenomenological predictions for neutrino mass patterns and mixing. These are the outcome of the interplay of several features, namely: i) the seesaw mechanism; ii) the presence of an intermediate scale where B-L gauge symmetry is broken and the right-handed neutrinos acquire a Majorana mass; iii) a symmetric Dirac neutrino mass matrix whose pattern is close to the up-type quark one. In this framework two natural characteristics emerge. Normal neutrino mass hierarchy is the only allowed, and there is an approximate relation involving both light-neutrino masses and mixing parameters. This differs from what occurring when horizontal flavour symmetries are invoked. In this case, in fact, neutrino mixing or mass relations have been separately obtained in literature. In this paper we discuss an example of such comprehensive mixing-mass relation in a specific realization of SO(10) and, in particular, analyse its impact on the expected neutrinoless double beta decay effective mass parameter 〈mee〉, and on the neutrino mass scale. Remarkably a lower limit for the lightest neutrino mass is obtained (mlightest ≳ 7.5 × 10−4 eV, at 3 σ level).

REST SOA Orchestration and BPM Platforms

1 SOA MODELINGAccording to [1] the Service Oriented Architecture (SOA) concept is based on the principle of developing reusable business service and building applications instead of building monolithic applications in silos.SOA has the potential to bridge the gap between business and technology, improve reuse of existing applications and interoperability with new ones. Some authors [2] consider that software services are the building blocks for SOA, and they can be composed to provide a more coarse grained functionality and to automate business processes.A modeling language is an artificial language that can be used to define system, information in the structure defined by the rules of the system. Rules are used to interpret the association of components in the system. There are two types of modeling languages - Graphical Modeling: it used a diagrammatic approach to represent the system. There are symbols and lines that connect the symbols which is used to display the relationship between the systems. Notations are used to define the constraints in the system.- Textual Modeling: it uses the keywords or special characters with parameters to represent certain information in natural language which can be used by computers for processing [3]. Expressions are used to link the relationship among the text.Service Oriented Modeling (SOM) is the first step to model services of SOA. According to the specialists [3], the approach for modeling SOA with the viewpoint from services is required. Various methods for serviceoriented modeling have been proposed to apply SOA in industrial and business environments by many researchers [4]. They can be seen in Table 1 below:Starting from this table we decided, based on the reviewed literature, to pay attention only to specific modeling approaches, which are more common and used today.1.1.SOAMLUML is used for general purpose modeling of SOA and create visual models. The services were modeled as objects and general purpose of the design was made by it. But when the degree of complexity increased it was not that efficient. This is how SoaML (Service oriented architecture Modeling Language) emerged: as a UML profile and meta-model for the modeling and design of services within a service-oriented architecture [3].SoaML was created to support the following features:* Indentifying services and their requirements.* Defining service consumers and providers as well as the service itself.* Specifying message pattern and protocols for the services.* Different Service classification schemes.* Integration and extension with OMG meta-models and BPMN.The Object Management Group (OMG) proposed SoaML in 2009 for representing SOA artifacts using Unified Modeling Language (UML) as a core-modeling standard. Moreover, a meta-model and a UML profile are provided in SoaML for the specification and design of service to SOA (meta-model for modeling the requirement for a service and UML for specifying services) [4].1.2.SOMFService Oriented Modeling Framework (SOMF) is a model driven engineering methodology which focuses on business process, and the IT is part of the lifecycle. It can also be used at standalone designing platform with other modeling languages such as UML, BPMN, or SoaML to enrich the language syntax. It can also set software development priorities during life cycle stages, and enhance the overall implementation view of the system [3].The SOMF offers specialized modeling notation to help model, analysis and identification services that is proposed by Bell. It provides a formal method of service identification at different levels of abstraction including meta-model concept and specific notation [4].1.3.SOMASOMA is a modeling technique for developing and building SOA-based systems proposed by IBM in 2004. SOMA activities focuses include: service identification (discovering candidate service and interaction between them), service specification (making decision for exposing services), and service realization (capturing service realization). …

Nonspherical Szekeres models in the language of cosmological perturbations

We study the differences and equivalences between the non-perturbative description of the evolution of cosmic structure furnished by the Szekeres dust models (a non-spherical exact solution of Einstein's equations) and the dynamics of Cosmological Perturbation Theory (CPT) for dust sources in a $\Lambda$CDM background. We show how the dynamics of Szekeres models can be described by evolution equations given in terms of "exact fluctuations" that identically reduce (at all orders) to evolution equations of CPT in the comoving isochronous gauge. We explicitly show how Szekeres linearised exact fluctuations are specific (deterministic) realisations of standard linear perturbations of CPT given as random fields but, as opposed to the latter perturbations, they can be evolved exactly into the full non-linear regime. We prove two important results: (i) the conservation of the curvature perturbation (at all scales) also holds for the appropriate approximation of the exact Szekeres fluctuations in a $\Lambda$CDM background, and (ii) the different collapse morphologies of Szekeres models yields, at nonlinear order, different functional forms for the growth factor that follows from the study of redshift space distortions. The metric based potentials used in linear CPT are computed in terms of the parameters of the linearised Szekeres models, thus allowing us to relate our results to linear CPT results in other gauges. We believe that these results provide a solid starting stage to examine the role of non-perturbative General Relativity in current cosmological research.

Modelling countervailing incentives in adverse selection models: A synthesis

This paper is concerned with countervailing incentives in the adverse selection problems that typically arise in principal-agent relationships when the agent has private information. These incentives are present when the agent is tempted to either overstate or understate his private information depending upon the specific realization of his type. These problems were first analyzed by Lewis and Sappington (1989) and have been characterized and extended by Maggi and Rodríguez-Clare (1995a) and Jullien (2000). In this paper we propose a simple method of characterizing countervailing incentives in which the key element is the analysis of the properties of the full information problem. Our method for solving the principal problem, once identified the presence of countervailing incentives, follows closely the Baron’s (1989) approach, which does not require using optimal control theory. The methodology we present can be easily applied to many different economic settings. For example, in health economics, an insurer (or a hospital manager) might act as a principal and a physician as an agent. In labor settings, an employer may play the role of principal and a worker may act as the agent. In regulated industries, the regulatory agency might act as a principal designing incentive schemes for firms (the agents). In environmental regulation or resource exploitation, the principal might be an international agency dealing with national governments or firms.

Real-time broadening of nonequilibrium density profiles and the role of the specific initial-state realization

The real-time broadening of density profiles starting from non-equilibrium states is at the center of transport in condensed-matter systems and dynamics in ultracold atomic gases. Initial profiles close to equilibrium are expected to evolve according to linear response, e.g., as given by the current correlator evaluated exactly at equilibrium. Significantly off equilibrium, linear response is expected to break down and even a description in terms of canonical ensembles is questionable. We unveil that single pure states with density profiles of maximum amplitude yield a broadening in perfect agreement with linear response, if the structure of these states involves randomness in terms of decoherent off-diagonal density-matrix elements. While these states allow for spin diffusion in the XXZ spin-1/2 chain at large exchange anisotropies, coherences yield entirely different behavior.

Composability and controllability of structural linear time-invariant systems: Distributed verification

Motivated by the development and deployment of large-scale dynamical systems, often comprised of geographically distributed smaller subsystems, we address the problem of verifying their controllability in a distributed manner. Specifically, we study controllability in the structural system theoretic sense, structural controllability, in which rather than focusing on a specific numerical system realization, we provide guarantees for equivalence classes of linear time-invariant systems on the basis of their structural sparsity patterns, i.e., the location of zero/nonzero entries in the plant matrices. Towards this goal, we first provide several necessary and/or sufficient conditions that ensure that the overall system is structurally controllable on the basis of the subsystems’ structural pattern and their interconnections. The proposed verification criteria are shown to be efficiently implementable (i.e., with polynomial time-complexity in the number of the state variables and inputs) in two important subclasses of interconnected dynamical systems: similar (where every subsystem has the same structure) and serial (where every subsystem outputs to at most one other subsystem). Secondly, we provide an iterative distributed algorithm to verify structural controllability for general interconnected dynamical system, i.e., it is based on communication among (physically) interconnected subsystems, and requires only local model and interconnection knowledge at each subsystem.

Fast Analysis of Unsteady Wing Aerodynamics via Stochastic Models

Lifting surfaces often operate in highly unsteady inflow conditions, such as gusty wind or waves. These inflows are unsteady on many time scales and have to be considered stochastic processes. For fluid dynamics practitioners, this leads to a challenge: how can long-term, random design loads (e.g., fatigue or 20 year return extreme) be quantified efficiently? The conventional approach involves analysis of a large set of short-term inflow realizations and extrapolates the results to long-term loads via their assumed probability distributions. However, this requires separately solving many simulations. This is computationally expensive and presents a handicap, especially in early design stages (optimization), where rapid evaluations of candidate designs and performance gradients are required. To tackle this problem, we introduce two alternative stochastic methods: one based on a Galerkin projection onto Fourier modes, and the other based on a polynomial chaos expansion. This approach enables us to carry the randomness though the solution process to directly obtain a stochastic result. Thus, long-term loads can be directly constructed from the stochastic solution, without having to analyze specific realizations of the inflow inputs. The new processes are illustrated and discussed with an example based on a rectangular wing lifting-line model.

Impeded Dark Matter

We consider dark matter models in which the mass splitting between the dark matter particles and their annihilation products is tiny. Compared to the previously proposed Forbidden Dark Matter scenario, the mass splittings we consider are much smaller, and are allowed to be either positive or negative. To emphasize this modification, we dub our scenario "Impeded Dark Matter". We demonstrate that Impeded Dark Matter can be easily realized without requiring tuning of model parameters. For negative mass splitting, we demonstrate that the annihilation cross-section for Impeded Dark Matter depends linearly on the dark matter velocity or may even be kinematically forbidden, making this scenario almost insensitive to constraints from the cosmic microwave background and from observations of dwarf galaxies. Accordingly, it may be possible for Impeded Dark Matter to yield observable signals in clusters or the Galactic center, with no corresponding signal in dwarfs. For positive mass splitting, we show that the annihilation cross-section is suppressed by the small mass splitting, which helps light dark matter to survive increasingly stringent constraints from indirect searches. As specific realizations for Impeded Dark Matter, we introduce a model of vector dark matter from a hidden $SU(2)$ sector, and a composite dark matter scenario based on a QCD-like dark sector.

Averaged controllability of parameter dependent conservative semigroups

We consider the problem of averaged controllability for parameter depending (either in a discrete or continuous fashion) control systems, the aim being to find a control, independent of the unknown parameters, so that the average of the states is controlled. We do it in the context of conservative models, both in an abstract setting and also analysing the specific examples of the wave and Schrödinger equations.Our first result is of perturbative nature. Assuming the averaging probability measure to be a small parameter-dependent perturbation (in a sense that we make precise) of an atomic measure given by a Dirac mass corresponding to a specific realisation of the system, we show that the averaged controllability property is achieved whenever the system corresponding to the support of the Dirac is controllable.Similar tools can be employed to obtain averaged versions of the so-called Ingham inequalities.Particular attention is devoted to the 1d wave equation in which the time-periodicity of solutions can be exploited to obtain more precise results, provided the parameters involved satisfy Diophantine conditions ensuring the lack of resonances.

Fast optimization of quasi‐periodic slow‐wave structures with applications to broadband microwave coupler miniaturization

AbstractThis work discusses design optimization of quasi‐periodic slow‐wave structures in the context of wideband branch‐line coupler miniaturization. Size reduction is achieved by using slow‐wave structures as substitutes for conventional transmission lines of the reference circuit. Selection of a specific cell realization as well as determination of a repetition factor of the quasi‐periodic slow‐wave structure is accomplished by optimization‐based theoretical studies. The principal design procedure involves cell optimization using electromagnetic simulations, local response surface approximation modeling of the single cell, and surrogate‐based optimization of the slow‐wave structure composed of cascaded cell approximation models. Surrogate‐assisted design closure is subsequently applied to account for T‐junction effects neglected in the preceding stages of the design process. The final coupler exhibits high‐performance operation over a 31% bandwidth and occupies only one third of the reference circuit area. The component obtained in this work illustrates the highest bandwidth‐to‐size ratio as compared to state‐of‐the‐art structures reported in the literature. In addition, the feasibility of the approach is confirmed by experimental data.