Kondo insulators in the periodic Anderson model: a local moment approach

The symmetric periodic Anderson model is well known to capture the essential physics of Kondo insulator materials. Within the framework of dynamical mean-field theory, we develop a local moment approach to its single-particle dynamics in the paramagnetic phase. The approach is intrinsically non-perturbative, encompasses all energy scales and interaction strengths, and satisfies the low-energy dictates of Fermi liquid theory. It captures in particular the strong coupling behaviour and exponentially small quasiparticle scales characteristic of the Kondo lattice regime, as well as simple perturbative behaviour in weak coupling. Particular emphasis is naturally given to strong coupling dynamics, where the resultant clean separation of energy scales enables the scaling behaviour of single-particle spectra to be obtained.Comment: 15 pages, 10 postscript figures, accepted for publication in EPJ B; HyperTex disable

Complementary two-way algorithms for negative radix conversions

This paper describes two sets of algorithms in positive radix arithmetic for conversions between positive and negative integral radix representation of numbers. Each set consists of algorithms for conversions in either direction; these algorithms are mutually complementary in the sense they involve inverse operations depending upon the direction of conversion. The first set of algorithms for conversion of numbers from positive to negative radix (negative to positive radix) proceeds serially from the least significant end of the number and involves complementation and addition (subtraction) of unity on single-digit numbers. The second set of algorithms for conversion of numbers from positive to negative radix (negative to positive radix) proceeds in parallel starting from the full number (the most significant end of the number) and involves complementation and right (left) shift operations. The applications of these algorithms to integers, mixed integer-fractions, floating-point numbers, and for real-time conversions are given

Self-organization and autonomy in computational networks: agents-based contractual workflow paradigm

We describe an agents-based contractual workflow paradigm for Self-organization and autonomy in computational networks. The agent-based paradigm can be interpreted as the outcome arising out of deterministic, nondeterministic or stochastic interaction among a set of agents that includes the environment. These interactions are like chemical reactions and result in self-organization. Since the reaction rules are inherently parallel, any number of actions can be performed cooperatively or competitively among the subsets of elements, so that the agents carry out the required actions. Also we describe the application of this paradigm in finding short duration paths, chemical- patent mining, and in cloud computing services

Contextual conflict determination among sensory events using cooperating agents

A cooperating-agents based algorithm is described to detect temporal consistency among sensory events and for constraint processing. We describe the algorithm using an example. Also we describe the cooperative aspects of the agent -based algorithm using an UML activity diagram

Cooperative agent-based software architecture for distributed simulation

This paper proposes a cooperative multiagent model using distributed object-based systems for supporting distributed virtual environment and distributed simulation technologies for military and government applications. The agent model will use the condition-event driven rule based system as the basis for representing knowledge. In this model, the updates and revision of beliefs of agents corresponds to modifying the knowledge base. These agents are reactive and respond to stimulus as well as the environment in which they are embedded. Further, these agents are smart and can learn from their actions. The distributed agent-based software architecture will enable us to realise human behaviour model environment and computer-generated forces (also called computer-generated actor (CGA)) architectures. The design of the cooperative agent-based architecture will be based on mobile agents, interactive distributed computing models, and advanced logical modes of programming. This cooperative architecture will be developed using Java based tools and distributed databases

Economic pseudodivision processes for obtaining square root, logarithm, and arctan

Modified Meggitt methods (pseudodivision methods) are suggested for evaluating logarithm, arctan, and square root. The modifications described here consist in restricting the magnitude of the pseudopartial remainsler such that the pseudoquotient assumes a form close to the minimal representation in the radix of choice. These methods will become useful for large-scale integrated system design

Coarsening and Slow-Dynamics in Granular Compaction

We address the problem of the microscopic reorganization of a granular medium under a compaction process in the framework of Tetris-like models. We point out the existence of regions of spatial organization which we call domains, and study their time evolution. It turns out that after an initial transient, most of the activity of the system is concentrated on the boundaries between domains. One can then describe the compaction phenomenon as a coarsening process for the domains, and a progressive reduction of domain boundaries. We discuss the link between the coarsening process and the slow dynamics in the framework of a model of active walkers on active substrates.Comment: Revtex 4 pages, 4 figures, in press in PRL. More info http://axtnt3.phys.uniroma1.it/Tetri

Ultrasonic Machining as an Aid to Ceramic Etching

Ceramics are difficult to etch. Their chemical inertness makes them very stable and often hot etching techniques are required to obtain their microstructures. This communication reports a technique developed to ease the process of ceramic etching

Self-Structuring of Granular Media under Internal Avalanches

We study the phenomenon of internal avalanching within the context of recently proposed ``Tetris'' lattice models for granular media. We define a recycling dynamics under which the system reaches a steady state which is self-structured, i.e. it shows a complex interplay between textured internal structures and critical avalanche behavior. Furthermore we develop a general mean-field theory for this class of systems and discuss possible scenarios for the breakdown of universality.Comment: 4 pages RevTex, 3 eps figures, revised version to appear in Phys. Rev. Let