Primitive Domain Research Articles

Analyticity of off-shell Green\u2019s functions in superstring field theory

We consider the off-shell momentum space Green’s functions in closed superstring field theory. Recently in [1], the off-shell Green’s functions — after explicitly removing contributions of massless states — have been shown to be analytic on a domain (to be called the LES domain) in complex external momenta variables. Analyticity of off-shell Green’s functions in local QFTs without massless states in the primitive domain is a well-known result. Using complex Lorentz transformations and Bochner’s theorem allow to extend the LES domain to a larger subset of the primitive domain. For the 2-, 3- and 4-point functions, the full primitive domain is recovered. For the 5-point function, we are not able to obtain the full primitive domain analytically, only a large part of it is recovered. While this problem arises also for higher-point functions, it is expected to be only a technical issue.

Transverse perturbation on three-dimensional ion acoustic waves in electron–positron–ion plasma with high-energy tail electron and positron distribution

The basic features of nonlinear ion acoustic (IA) waves are theoretically studied in a superthermal electron–positron–ion (e–p–i) plasma with weakly transverse perturbation. A three-dimensional Kadomtsev–Petviashvili (KP) equation governing evolution of weakly nonlinear IA waves is derived by means of a reductive perturbation method. The energy integral equation is used to study the existence domain of the localized structures. It is found that deviation from thermodynamics equilibrium increases the existence domain of solitary solution and also makes the IA solitary structure more spiky. The ion concentration has an important effect on the existence domain of solitary solution, as for low ion density the primitive domain reduces significantly.

Rethinking Time Geography in the Information Age

As everyday activities are increasingly carried out at least in part through digitally mediated remote interaction, researchers interested in the complex relationships between urban activities, spaces, and travel are running up against the limits of familiar forms of time geography. This paper argues that because information and communication technologies (ICTs) are loosening the traditionally close links between activity, place, and time, physicalist models such as the space–time path and prism of time geography may need to be reexamined in light of the new realities. An important part of these new realities is the fact that virtual communications depend on specific kinds of material means (computers and mobile phones, in particular). These now compete with and complement a fundamentally different kind of material means (of physical transportation) which have traditionally been at the basis of time-geographic analyses. The paper proposes a novel conceptual framework for time geography, whereby people's space–time behavior is modeled not just in a three-dimensional space but in a multidimensional space. The framework amounts to a primitive domain ontology for conceptualizing human activity in an ICT-rich world, and can naturally accommodate activity in cyberspace as well as in physical space. The objectives are: (1) to expand our ability to understand activities in space and time in the age of ICT by explicitly representing choices of means (here, transportation-related and communication-related means) to serve specific ends: to be most useful, this should be done within the same model that also tracks people's spatiotemporal trajectories; (2) more specifically, to improve our ability to represent and analyze the increasing variety of activities carried out with the help of ICT as these relate to time and place, and (3) to do so in a way that conserves the power of traditional time geography and is practical enough to be implemented. A few simple examples are discussed and illustrated with the help of parallel coordinates plots.

3D Triangular Mesh Parameterization with Semantic Features Based on Competitive Learning Methods

In 3D computer graphics, mesh parameterization is a key technique for digital geometry processings such as morphing, shape blending, texture mapping, re-meshing and so on. Most of the previous approaches made use of an identical primitive domain to parameterize a mesh model. In recent works of mesh parameterization, more flexible and attractive methods that can create direct mappings between two meshes have been reported. These mappings are called “cross-parameterization” and typically preserve semantic feature correspondences between target meshes. This paper proposes a novel approach for parameterizing a mesh into another one directly. The main idea of our method is to combine a competitive learning and a least-square mesh techniques. It is enough to give some semantic feature correspondences between target meshes, even if they are in different shapes or in different poses.

A robust adaptive feedforward method for the compensation of harmonic disturbances

Most of disk drives suffer from various disturbances that degrade read–write performances. As the track density rapidly increases, basic drive functions may fail even with a small scale disturbance in a normal operating environment. For the reason, an accurate identification of the repeatable runout (RRO) of a hard disk drive has been one of the most important tasks for the successful servo designs in modern hard disk drive integration. Extensive research efforts have been dedicated for the compensation of the runouts and produced many successful strategies to minimize the influences to the critical basic drive functions. Primarily for the simple implementation and the cost reduction in the actual drive development and manufacturing, most of the developed methods being used in the actual drive integration are preferred to be formulated on time domain or frequency domain with very basic limited functions. The primitive frequency domain approaches usually require extensive calculations and large physical memories. In the present work, a RRO compensation method that combines advantages of the transient Fourier coefficients (TFC) and the least mean square (LMS) update is introduced. Combining the two methods in a proper fashion, the present work provides many benefits for the drive design and outperforms the previous compensation methods. The proposed method requires significantly less amount of computational work and physical memories compared to the conventional runout compensation methods. And it also provides effective frequency component selectivity so that the compensation resources are to be concentrated to a specific problem reason. Comprehensive frequency domain formulation of the method followed by a series of experimental test results is provided in the present article.

Using Java reflection to automate extension language parsing

An extension language is an interpreted programming language designed to be embedded in a domain-specific framework. The addition of domain-specific primitive operations to an embedded extension language transforms that vanilla extension language into a domain-specific language. The LUxWORKS processor simulator and debugger from Lucent uses Tcl as its extension language. After an overview of extension language embedding and LUxWORKS experience, this paper looks at using Java reflection and related mechanisms to solve three limitations in extension language - domain framework interaction. The three limitations are gradual accumulation of ad hoc interface code connecting an extension language to a domain framework, over-coupling of a domain framework to a specific extension language, and inefficient command interpretation. Java reflection consists of a set of programming interfaces through which a software module in a Java system can discover the structure of classes, methods and their associations in the system. Java reflection and a naming convention for primitive domain operations eliminate ad hoc interface code by supporting recursive inspection of a domain command interface and translation of extension language objects into domain objects. Java reflection, name-based dynamic class loading, and a language-neutral extension language abstraction eliminate language over-coupling by transforming the specific extension language into a runtime parameter. Java reflection and command objects eliminate inefficiency by bypassing the extension language interpreter for stereotyped commands. Overall, Java reflection helps to eliminate these limitations by supporting reorganization and elimination of handwritten code, and by streamlining interpretation.

Evolution of glycolytic enzymes.

The requirements for glycolysis are examined in relation to other essential metabolic processes in the most primitive organisms. The construction of more complex enzymes from primitive domain building blocks is assessed with respect to glycolytic enzymes. Special attention is given to the evolution of the NAD binding domain in dehydrogenases and the related, frequently observed nucleotide binding domain. An attempt is made to differentiate between convergence and divergence of frequently observed domains. Consideration is given to the structure-function relation of these domains and the development of quaternary structure in later stages of evolution. Some attention is also given to the evolution of the structural adaptation to extreme environments as a means of differentiating between essential functions and specific modifications.

Analyticity properties implied by the many-particle structure of then-point function in general quantum field theory

This is the first of a series of papers devoted to the derivation of analyticity properties in the non-linear program of general quantum field theory, following the line of the “many particle structure analysis” due to Symanzik. In this preliminary paper, “convolution products” are associated with graphs whose verticesv represent generalnv-point functions. Under convergence assumptions in Euclidean directions, it is proved that any such convolution productHG associated with a graphG withN external lines is well defined as an analytic function of the correspondingN four-momentum variables. The analyticity domain ofHG is proved to contain the correspondingN-point “primitive domain” implied by causality and spectrum and the various real boundary values ofHG satisfy all the relevant linear relations. For appropriate boundary values, the convolution products generalize the perturbative Feynmann prescription. As a by-product of this study, it is proved that in any perturbative theory using “superpropagators” with Euclidean convergence, Feynmann amplitudes that satisfy all the requirements of the linear program can be defined without the help of a regularization.

Perturbation Analyticity and Axiomatic Analyticity. I. Connection of the Landau Singularity Manifold with KällénΞn(t)Manifold and Jost DANAD Manifold

For a class of Feynman graphs ${\mathcal{G}}_{n}$ (single-loop diagrams with all internal diagonals), the $p$-space perturbation Landau singularity manifolds are shown to be formally of the same structure as the K\"all\'en ${\ensuremath{\Xi}}_{n}(t)$ manifolds for the $x$-space axiomatic primitive domain. The boundary of the Landau manifold is then shown to be the (DANAD)\ensuremath{'} manifold. The relationship between the (DANAD)\ensuremath{'} and the Jost (DANAD) manifold is a precise generalization of what exists between the ${{F}_{\mathrm{kl}}}^{\ensuremath{'}}$ and ${F}_{\mathrm{kl}}$ surfaces of K\"all\'en and Wightman. Since the (DANAD)\ensuremath{'} defines a natural domain of holomorphy, the axiomatic envelope of holomorphy cannot be expected to be continuable beyond (DANAD)\ensuremath{'}. This (DANAD)\ensuremath{'} result furnishes a specific conjecture to part of the envelope of holomorphy.

Some rigorous analyticity properties of the four-point function in momentum space

Geometrical methods of analytic completion are used to enlarge the primitive domain of analyticity of the four-point function inp-space. The results imply, in particular, analyticity of the scattering amplitude in two variables, on the mass shell, near all physical points, as well as analyticity of partial-wave amplitudes ins near the physical points of the right-hand side cut.