bluuebunny/crossref_metadata_2025 huggingface dataset:
A Generic MPI Implementation for a Data-Parallel Skeleton: Formal Derivation and Application to FFT
Authors: Gorlatch Sergei , Bischof Holger
Published: September 2003

We derive a provably correct, architecture-independent family of parallel implementations for a class of data-parallel algorithms, called DH (distributable homomorphisms). The implementations are well-structured SPMD programs with group-wise personalized all-to-all exchange, directly realizable in MPI. As a case study, we systematically adjust the mathematical specification of the Fast Fourier Transform (FFT) to the DH format and, thereby, obtain a generic SPMD implementation for FFT. The target program includes FFT solutions used in practice – the binary-exchange and the 2D- and SD-transpose – as special cases.
Using Model Checking in a Parallelizing Compiler
Authors: Rus Teodor , van Wyk Eric
Published: September 2003

In this paper we describe the usage of temporal logic model checking in a parallelizing compiler to analyze the structure of a source program and locate opportunities for optimization and parallelization. The source program is represented as a process graph in which the nodes are sequential processes and the edges are control and data dependence relationships between the computations at the nodes.

By labeling the nodes and edges with descriptive atomic propositions and by specifying the conditions necessary for optimizations and parallelizations as temporal logic formulas, we can use a model checker to locate nodes of the process graph where particular optimizations can be made. To discover opportunities for new optimizations or modify existing ones in this parallelizing compiler, we need only specify their conditions as temporal logic formulas; we do not need to add to or modify the code of the compiler. This greatly simplifies the process of locating optimization and parallelization opportunities in the source program and makes it easier to experiment with complex optimizations. Hence, this methodology provides a convenient, concise, and formal framework in which to carry out program optimizations by compilers.
Derivation of an Algorithm for Location Management for Mobile Communication Devices
Authors: Sanders Beverly A. , Massingill Berna L. , Kryukova Svetlana
Published: September 2003

In a network supporting mobile communication devices, a mechanism to find the location of a device, wherever it may be, is needed. In this paper, we present a distributed algorithm for this purpose along with its formal specification and proof sketch. Starting with an algorithm due to Wang, the process of formalization together with careful attention to abstraction leads to a more regular, general, and robust algorithm with a clearer description. An incidental contribution is a useful theorem for proving progress properties in distributed algorithms that use tokens.
A Novel Algorithm and its Hardware Support for the Run-Time Detection of And-Parallelism
Authors: Marsh Andy
Published: September 2003

It is well established in query evaluation literature that pushing constants (i.e. bound variable values) through selections, enables the problem specific information to be used effectively and is essential for constraining a query's search space. This amounts to a decision on how information gained about bindings in some body atom in a clause is to be used in evaluating other atoms in the clause. This binding passing algorithm is referred to in deductive database literature as a 'sideways information passing strategy' (sip). A sip that is determined at compile-time for uncovered definite clauses can only devise the most general sip and therefore may be sub-optimal at run-time. A sip determined at run-time is however inefficient - overheads outweigh advantages. To overcome these dilemmas a dynamic sip has been devised that uses a hybrid compile-time analysis, based on abstract interpretation, combined with a run-time verification. The pragmatics of the run-time verification is presented in this paper along with its novel hardware support providing a uniform performance of 155ns independent of the number of body atoms to detect an initial processing order for the independent atoms.
On the Computing Power of Arrays of Processors with Optical Pipelined Buses
Authors: Hamdi M. , Qiao C. , Pan Y.
Published: September 2003

This paper examines the computing power of optical parallel computer systems. We consider the proposed Array of Processors with optical Pipelined Buses (APPB) in particular, where processors communicate with each other via a spanning optical bus. APPB allow simultaneous access by multiple processors to the optical bus through message pipelining, thus overcoming the bottlenecks caused by exclusive access when employing electronic buses. We give an overview of this model of parallel computation, and then examine the computing power of APPB by demonstrating its capability to efficiently emulate the CRCW PRAM model. We show that an APPB is almost as powerful as a CRCW PRAM. That is, an APPB can emulate a CRCW PRAM with only a small degradation in time performance.
A One-Phase Parallel Algorithm for the Sequence Alignment Problem
Authors: Lecroq Thierry , Myoupo Jean-Frederic , Seme David
Published: September 2003

This paper introduces a new linear systolic algorithm [10] for the sequence alignment problem [18]. It is made up of min(n, m) processors and computes the edit distance and the sequence alignment of two sequences Target and Source in time min(n, m) + 2.max(n, m), where n and m denote the lengths of Target and Source respectively. Its characteristics make it faster and more efficient than the previous linear array algorithm for the alignment search.
The Parallel Complexity of Positive Linear Programming
Authors: Trevisan Luca , Xhafa Fatos
Published: September 2003

In this paper we study the parallel complexity of Positive Linear Programming (PLP), i.e. the special case of Linear Programming in packing/covering form where the input constraint matrix and constraint vector consist entirely of positive entries. We show that the problem of exactly solving PLP is P-complete.
Using Parallel Processing as a Computational Tool to Solve Multi-Plate Electromagnetic Scattering Problems
Authors: Marsh Andy , Kaklamani Dimitra I. , Adam Konstantinos
Published: September 2003

The Parallel Method of Moments (PMoM) technique is used to solve electrically large multi-plate scattering problems. After introducing the PMoM, an integral equation formulation in conjunction with an entire domain Galerkin technique is employed to analyse the multi-plate scattering problem. The resulting algorithm parallelisation enables for the proposed approach to be applied above the resonance region. Numerical results and computational times concerning a specific worked example are presented, using High Performance Computing purely as a computational tool.
Genetic Programming to Design Communication Algorithms for Parallel Architectures
Authors: Comellas F. , Gimenez G.
Published: September 2003

Broadcasting is an information dissemination problem in which a message originating at one node of a communication network (modeled as a graph) is to be sent to all other nodes as quickly as possible. This paper describes a new way of producing broadcasting schemes using genetic programming. This technique has proven successful by easily finding optimal algorithms for several well-known families of networks (grids, hypercubes and cycle connected cubes) and has indeed generated a new scheme for butterflies that improves the known upper bound for the broadcasting time of these networks.
Matrix Transposition on a Mesh with Blocking Transmissions
Authors: Hofri Micha , Thomson David L.
Published: September 2003

A time-optimal procedure to transpose in situ a matrix stored over a distributed memory 2-dimensional mesh-connected parallel computer is shown. The matrix need not be square. Only nearest-neighbor blocking communications is used, and a small bounded buffer space is required.
Optimally Routable Networks
Authors: Farley Arthur M.
Published: September 2003

Routing is the process, performed at each site of a communication network upon receipt of a message, that decides to which neighbor the message is to be sent or that the message is to be received locally. We present a general model of routing based on a decision tree representation of routing information. We describe several classes of optimally routable networks, i.e., networks for which the maximum size of a routing tree over all sites of the network is ⌈log2 n⌉.
Segment Directory: An Improvement to the Pointer in Directory Cache Coherence Schemes
Authors: Choi Jong Hyuk , Park Kyu Ho
Published: September 2003

We propose a new directory element called the segment directory, which is a hybrid of the full map vector and the pointer. It can be used in place of the pointer in most pointer-based directory schemes to improve directory storage efficiency: a segment directory element can point to several processors with almost the same number of bits as the pointer which can point to only one. In this paper, the segment directory is applied to four of the limited directory schemes, and performance improvement is then evaluated. The segment directory eliminates directory overflows by up to 71% and reduces the traffic and execution time of all the workloads run on the four schemes. This is the first effort in literature to reduce directory overflows themselves. Moreover, the segment directory does not introduce additional hardware overhead or protocol complexity.
Specification of the Behavior of Memory Operations in Distributed Systems
Authors: Cholvi Vicent
Published: September 2003

Shared memory is a mechanism used for inter-process communication in distributed systems which is considered a feasible alternative to the traditional communication model.

However, most of the work on shared memory has not paid enough attention to the way memory operations behave, leading to some degree of confusion.

In this paper, we describe a framework for specifying the behavior of memory operations. That framework has been used to formally specify some of the most significant memory models. In this framework, to characterize a memory model it is enough to specify the executions that it allows.

We use a dual approach. First, we provide axiomatic definitions of those memory models; then, we provide operational ones. Whereas axiomatic definitions are simple and intuitive, operational definitions are more convenient for being used in correctness proofs. We show that both approaches are equivalent.
Phase Separation Due to Nearest Neighbor Attractive Interactions in a Two-Dimensional Model
Authors: Shaw M. , Su W. P.
Published: September 2003

We have studied a correlated fermion model with nearest neighbor attractive interactions on a square lattice by means of quantum Monte Carlo simulation. At half-filling this model exhibits rather strong correlation effects. Charge fluctuations are suppressed and the ground state is an insulator with long-range anitferromagnetic correlations. When doped with holes this model exihibits phase separation which seems to be triggered by the antiferromagnetic long-range correlations.
Quantum Phase Transition and Engineering in Two-Component BEC in Optical Lattices
Authors: Wu Yong-Shi
Published: September 2003

In this paper we review recent progress in studying quantum phase transitions in one- and two-component Bose–Einstein condensates (BEC) in optical lattices. These phase transitions involve the emergence and disappearance of quantum coherence over the whole optical lattice and of linear superposition of macroscopic quantum states. The latter may provide new means to engineer and manipulate novel macroscopic quantum states and novel coherent atomic beams for quantum information processing, quantum computing and other purposes.
Fermion Zero Modes Around Skyrmions in the t′-J Model
Authors: Kou Su-Peng
Published: September 2003

Using the t′-J model, we study the effects of skyrmions in doped antiferromagnets. For the π flux phase, the low energy effective theory of the t′-J model can be mapped onto N=2 2+ 1D σ3-quantum electrodynamics. There exist fermion zero modes around skyrmions. Two holons of different sublattices are bound onto skyrmions as a bosonic composite object.
The Role of Middleware in Architecture-Based Software Development
Authors: Medvidovic Nenad , Dashofy Eric M. , Taylor Richard N.
Published: September 2003

Software architectures promote development focused on modular functional building blocks (components), their interconnections (configurations), and their interactions (connectors). Since architecture-level components often contain complex functionality, it is reasonable to expect that their interactions will be complex as well. Middleware technologies such as CORBA, COM, and RMI provide a set of predefined services for enabling component composition and interaction. However, the potential role of such services in the implementations of software architectures is not well understood. In practice, middleware can resolve various types of component heterogeneity — across platform and language boundaries, for instance — but also can induce unwanted architectural constraints on application development. We present an approach in which components communicate through architecture-level software connectors that are implemented using middleware. This approach preserves the properties of the architecture-level connectors while leveraging the beneficial capabilities of the underlying middleware. We have implemented this approach in the context of a component- and message-based architectural style called C2 and demonstrated its utility in the context of several diverse applications. We argue that our approach provides a systematic and reasonable way to bridge the gap between architecture-level connectors and implementation-level middleware packages.
A Service Architecture for Mobile Teamwork
Authors: Kirda Engin , Gall Harald
Published: September 2003

Mobile teamwork has become an emerging requirement in the daily business of large enterprises. Employees collaborate across locations and need team support while they are on the move. Business documents and expertise need to be shared independent of the actual location or connectivity (e.g., access through a mobile phone, laptop, Personal Digital Assistant, etc.) of employees. Although many collaboration tools and systems exist, most do not deal with new demanding requirements such as locating artifacts and experts through distributed searches, advanced information subscription and notification, and mobile information sharing and access. The MOTION service architecture that we have developed supports mobile teamwork by taking into account the different connectivity modes of users, provides access support for various devices such as laptop computers and mobile phones, and uses XML meta data and the XML Query Language (XQL) for distributed searches and subscriptions. In this article, we describe the architecture and the components of our generic MOTION services platform for building collaborative applications. The MOTION platform is currently being evaluated in two large industry case-studies.
Template-Based Generation of Multimedia Presentations
Authors: Celentano Augusto , Gaggi Ombretta
Published: September 2003

Data-centered approaches to multimedia presentation design and implementation can be developed by extending methodologies and technologies common in text-based applications. A multimedia report is a multimedia presentation built on a set of data returned by one or more queries to multimedia repositories, integrated according to a template with appropriate spatial layout and temporal synchronization, and coherently delivered to a user for browsing. We discuss the problem of defining templates for such multimedia reports with a focus on media coordination and synchronization. Multimedia presentations can be automatically generated according to the template by instantiating it on actual data instances. An XML language describes the spatial layout and the temporal constraints of the media objects. An authoring system and a player have been implemented.
Towards Industrially Relevant Fault-Proneness Models
Authors: Denaro Giovanni , Pezzè Mauro , Morasca Sandro
Published: September 2003

Estimating software fault-proneness early, i.e., predicting the probability of software modules to be faulty, can help in reducing costs and increasing effectiveness of software analysis and testing. The many available static metrics provide important information, but none of them can be deterministically related to software fault-proneness. Fault-proneness models seem to be an interesting alternative, but the work on these is still biased by lack of experimental validation.

This paper discusses barriers and problems in using software fault-proneness in industrial environments, proposes a method for building software fault-proneness models based on logistic regression and cross-validation that meets industrial needs, and provides some experimental evidence of the validity of the proposed approach.
Trade-off Analysis for Requirements Selection
Authors: Ruhe Günther , Eberlein Armin , Pfahl Dietmar
Published: September 2003

Evaluation, prioritization and selection of candidate requirements are of tremendous importance and impact for subsequent software development. Effort, time as well as quality constraints have to be taken into account. Typically, different stakeholders have conflicting priorities and the requirements of all these stakeholders have to be balanced in an appropriate way to ensure maximum value of the final set of requirements. Trade-off analysis is needed to proactively explore the impact of certain decisions in terms of all the criteria and constraints.

The proposed method called Quantitative WinWin uses an evolutionary approach to provide support for requirements negotiations. The novelty of the presented idea is four-fold. Firstly, it iteratively uses the Analytical Hierarchy Process (AHP) for a stepwise analysis with the aim to balance the stakeholders' preferences related to different classes of requirements. Secondly, requirements selection is based on predicting and rebalancing its impact on effort, time and quality. Both prediction and rebalancing uses the simulation model prototype GENSIM. Thirdly, alternative solution sets offered for decision-making are developed incrementally based on thresholds for the degree of importance of requirements and heuristics to find a best fit to constraints. Finally, trade-off analysis is used to determine non-dominated extensions of the maximum value that is achievable under resource and quality constraints. As a main result, quantitative WinWin proposes a small number of possible sets of requirements from which the actual decision-maker can finally select the most appropriate solution.
The Linear Growth in the Lengths of a Family of Thick Knots
Authors: Diao Y. , Ernst C. , Thistlethwaite M.
Published: September 2003

For any given knot K, a thick realization K0 of K is a knot of unit thickness which is of the same knot type as K. In this paper, we show that there exists a family of prime knots {Kn} with the property that Cr (Kn)→∞( as n→∞) such that the arc-length of any thick realization of Kn will grow at least linearly with respect to Cr (Kn).
A Move on Diagrams that Generates S-Equivalence of Knots
Authors: Naik Swatee , Stanford Theodore
Published: September 2003

Two knots in three-space are S-equivalent if they are indistinguishable by Seifert matrices. We show that S-equivalence is generated by the doubled-delta move on knot diagrams. It follows as a corollary that a knot has trivial Alexander polynomial if and only if it can be undone by doubled-delta moves.
On Weight Systems Derived from Heisenberg Lie Algebras
Authors: Nishihara Hideaki
Published: September 2003

Weight systems are constructed with solvable Lie algebras and their infinite dimensional representations. With a Heisenberg Lie algebra and its polynomial representations, the derived weight system vanishes on Jacobi diagrams with positive loop-degree on a circle, and it is proved that the derived knot invariant is the inverse of the Alexander-Conway polynomial.
Trivial Double-Torus Knot
Authors: Hayashi Chuichiro
Published: September 2003

A knot K in a closed connected orientable 3-manifold M is called a double-torus knot, if it is in a genus two Heegaard splitting surface H of M. We give a necessary and sufficient condition for a double-torus knot to be the trivial knot in words of meridian disks of genus two handlebodies obtained by splitting M along H.
Link Invariant for the Spinor Representation of $\frak{so}_7$
Authors: Patureau-Mirand Bertrand
Published: September 2003

Pulling back the weight system associated with the spinor representation of the Lie algebra [Formula: see text] by the universal Vassiliev-Kontsevich invariant yields a numerical link invariant with values in formal power series. Computing some skein relations satisfied by this invariant, I derive a recursive algorithm for its evaluation. The values of this invariant belong to the ring ℤ[W,W-1] of Laurent polynomials in one variable.
Alexander Polynomial of Sextics
Authors: Oka Mutsuo
Published: September 2003

Alexander polynomials of sextics are computed in the case of sextics with only simple singularities or sextics of torus type with arbitrary singularities. We will show that for irreducible sextics, there are only 4 possible Alexander polynomials: (t2-t+1)j, j=0,1,2,3. For the computation, we use the method of Libgober and Loeser-Vaquié [5, 7] and the classification result in our previous papers [12, 11].
Diagrammatic Unknotting of Knots and Links in the Projective Space
Authors: Mroczkowski Maciej
Published: September 2003

In the classical knot theory there is a well-known notion of descending diagram. From an arbitrary diagram one can easily obtain, by some crossing changes, a descending diagram which is a diagram of the unknot or unlink. In this paper the notion of descending diagram for knots and links in ℝ3 is extended to the case of nonoriented knots and links in the projective space. It is also shown that this notion cannot be extended to oriented links.
Quantum Invariants of Templates
Authors: Kauffman Louis H. , Saito Masahico , Sullivan Michael C.
Published: September 2003

We define invariants for templates that appear in certain dynamical systems. Invariants are derived from certain bialgebras. Diagrammatic relations between projections of templates and the algebraic structures are used to define invariants. We also construct 3-manifolds via framed links associated to tamplate diagrams, so that any 3-manifold invariant can be used as a template invariant.
Thinning Genus Two Heegaard Spines in S3
Authors: Scharlemann Martin , Thompson Abigail
Published: September 2003

We study trivalent graphs in S3 whose closed complement is a genus two handlebody. We show that such a graph, when put in thin position, has a level edge connecting two vertices.
Simplified Resonating-Group Method for Light-Ion Scattering
Authors: Kaneko Tsuneo , Tang Y. C.
Published: September 2003

A simplified version of the resonating-group method, called model K, is discussed. In this model, the simplifications made are to approximate recoil effects and to take only the direct and the knockon-exchange terms into explicit consideration. It is a microscopic model for nucleus + nucleus scattering which works well in situations where the scattering energy is relatively high, and medium and heavy-weight target nuclei are involved. Applications of this model to s-shell-ion scattering show that, with the addition of a phenomenological imaginary potential into the formulation, good fits to experimental data can be achieved with only minor parameter adjustments. The properties of the internuclear local potential, equivalent to the model-K nonlocal interaction through the WKB procedure, have also been studied. Here it is found that the energy dependence of the empirically determined local potential can be largely accounted for by a proper consideration of exchange effects inherent in calculations employing totally antisymmetric wave functions.
Electromagnetic Form Factors and Static Properties of the Nucleons in a Chiral Symmetric Quark Model
Authors: Jena S. N. , Behera M. R.
Published: September 2003

Nucleon charge and magnetic form factors [Formula: see text] are computed in an independent-quark model with an equally mixed scalar and vector confining potential in square root form taking into account the corrections due to center-of-mass motion and pion-clound effects. The values obtained for the nucleon static properties such as the magnetic moment, charge radius and axial vector coupling constant in the neutron beta decay process agree reasonably with the corresponding experimental data. The pseudo-scalar and pseudo-vector pion-nucleon coupling constants are found to be gNNπ=13.43 and fNNπ=0.282, which are in excellent agreement with the experimental data.
Two-Body Dirac Equation Approach to the Deuteron
Authors: Galeão A. P. , Alcarás J. A. Castilho , Ferreira P. Leal
Published: September 2003

The two-body Dirac(Breit) equation with potentials associated to one-boson-exchanges with cutoff masses is solved for the deuteron and its observables calculated. The 16-component wave-function for the Jπ=1+ state contains four independent radial functions which satisfy a system of four coupled differential equations of first order. This system is numerically integrated, from infinity towards the origin, by fixing the value of the deuteron binding energy and imposing appropriate boundary conditions at infinity. For the exchange potential of the pion, a mixture of direct plus derivative couplings to the nucleon is considered. We varied the pion-nucleon coupling constant, and the best results of our calculations agree with the lower values recently determined for this constant.
Dissipation, Entropy, Chaos in Quantum Physics
Authors: Danos Michael
Published: September 2003

As a consequence of the Heisenberg uncertainty any quantum physics system inescapably undergoes relaxation towards thermal equilibrium, thus towards maximum entropy. The non-dissipative states have probability measure zero and cannot exist in nature. The impact these results have on chaotic behavior of quantum systems will be discussed, as well as the difference between quantum and classical systems, which have vanishing uncertainty.
Self-Consistent Pushing and Cranking Corrections to the Meson Fields of the Chiral Quark-Loop Soliton
Authors: Schleif M. , Wünsch R. , Maissner T.
Published: September 2003

We study translational and spin-isospin symmetry restoration for the two-flavor chiral quark-loop soliton. Instead of a static soliton at rest we consider a boosted and rotating hedgehog soliton. Corrected classical meson fields are obtained by minimizing a corrected energy functional which has been derived by semi-classical methods (variation after projection).

We evaluate corrected meson fields in the region 300 MeV ≤ M≤ 600 MeV of constituent quark masses M and compare them with the uncorrected fields. We study the effect of the corrections on various expectation values of nuclear observables such as the root-mean square radius, the axial-vector coupling constant, magnetic moments and the delta-nucleon mass splitting.
Testing Nucleon Strangeness in Polarization Effects for n+p→d+η
Authors: Koru H. , Rekalo M. P.
Published: September 2003

Charge symmetry of strong interaction results in a simplified spin structure of amplitude for n+p→d+η in "orthogonal" kinematics, where the η-production angle is equal to 90° in CMS. The presence of singlet and triplet amplitudes in such kinematics induces a rich set of different polarization observables, sensitive to the relative value of these amplitudes. This can be used to test a hypothesis of singlet enhancement of η-production in NN- and [Formula: see text]-collisions, due to a nonperturbative [Formula: see text]-component of the nucleon with special polarization properties.
Isospin Physics in Heavy-Ion Collisions at Intermediate Energies
Authors: Li Bao-An , Ko Che Ming , Bauer Wolfgang
Published: September 2003

In nuclear collisions induced by stable or radioactive neutron-rich nuclei a transient state of nuclear matter with an appreciable isospin asymmetry as well as thermal and compressional excitation can be created. This offers the possibility to study the properties of nuclear matter in the region between symmetric nuclear matter and pure neutron matter. In this review, we discuss recent theoretical studies of the equation of state of isospin-asymmetric nuclear matter and its relations to the properties of neutron stars and radioactive nuclei. Chemical and mechanical instabilities as well as the liquid-gas phase transition in asymmetric nuclear matter are investigated. The in-medium nucleon-nucleon cross sections at different isospin states are reviewed as they affect significantly the dynamics of heavy ion collisions induced by radioactive beams. We then discuss an isospin-dependent transport model, which includes different mean-field potentials and cross sections for the proton and neutron, and its application to these reactions. Furthermore, we review the comparisons between theoretical predictions and available experimental data. In particular, we discuss the study of nuclear stopping in terms of isospin equilibration, the dependence of nuclear collective flow and balance energy on the isospin-dependent nuclear equation of state and cross sections, the isospin dependence of total nuclear reaction cross sections, and the role of isospin in preequilibrium nucleon emissions and subthreshold pion production.
Nuclear G-Matrix Elements from Nonlocal Potentials
Authors: Yoshida K. , Hosaka A. , Oka M.
Published: September 2003

We study effects of nonlocality in the nuclear force on the G-matrix elements for finite nuclei. Nuclear G-matrix elements for 16O are calculated in the harmonic oscillator basis from a nonlocal potential which models quark exchange effects between two nucleons. We employ a simple form of potential that gives the same phase shifts as a realistic local nucleon potential. The G-matrix elements calculated from the nonlocal potential show moderate increase in repulsion from those derived from the local potential.
A Self-Consistent Treatment of Damped Motion for Stable and Unstable Collective Modes
Authors: Hofmann H. , Kiderlen D.
Published: September 2003

We address the dynamics of damped collective modes in terms of first and second moments. The modes are introduced in a self-consistent fashion with the help of a suitable application of linear response theory. Quantum effects in the fluctuations are governed by diffusion coefficients Dμν. The latter are obtained through a fluctuation dissipation theorem generalized to allow for a treatment of unstable modes. Numerical evaluations of the Dμν are presented. We discuss briefly how this picture may be used to describe global motion within a locally harmonic approximation. Relations to other methods are discussed, like "dissipative tunneling", RPA at finite temperature and generalizations of the "Static Path Approximation".
The Neutrino Reaction in 3H
Authors: Mintz S. L. , Gerstner G. M. , Barnett M. A. , Pourkaviani M.
Published: September 2003

We calculate the cross sections for the reactions, νe+3 H → e-+3 He , and νμ+3 H → μ-+3 He from threshold to 1 GeV. We obtain typical contributions of the individual form factors as well as the interference terms to the cross sections. We find that the cross sections for these processes are extremely large for a number of reasons, making them worthy of consideration for possible experiments. We also obtain a typical differential cross section and note the presence of sharp minima for high neutrino energies.
Nonlinear Effects in Nuclear Cluster Problem
Authors: Kartavenko V. G. , Gridnev K. A. , Greiner W.
Published: September 2003

Some nonlinear aspects of a cluster phenomenon in nuclei are considered using cubic Nonlinear Schrödinger equation and Korteveg de Vries equation. We discuss the following possible nonlinear effects: i) describing clusters as solitons; ii) an anomalous large angle scattering of α-particles by light and intermediate nuclei; iii) stable vortical objects; iv) and dynamical clusterization in the presence of instability.
Neutron Star Properties with Relativistic Equations of State
Authors: Huber H. , Weber F. , Weigel M. K. , Schaab Ch.
Published: September 2003

We study the properties of neutron stars adopting relativistic equations of state of neutron star matter, calculated in the framework of the relativistic Brueckner–Hartree–Fock approximation for electrically charge neutral neutron star matter in beta–equilibrium. For higher densities more baryons (hyperons etc.) are included by means of the relativistic Hartree– or Hartree–Fock approximation. The special features of the different approximations and compositions are discussed in detail. Besides standard neutron star properties special emphasis is put on the limiting periods of neutron stars, for which the Kepler criterion and gravitation–reaction instabilities are considered. Furthermore the cooling behaviour of neutron stars is investigated, too. For comparison we also give the outcome for some nonrelativistic equations of state.
On Z=2 Projectile Fragments Emitted in the Interactions of 3.7A GeV 28Si in Nuclear Emulsions
Authors: Singh B. K. , Tuli S. K.
Published: September 2003

We report the results on partial production cross sections for Z=2 projectile fragments emitted in 28Si-emulsion interactions at 3.7 A GeV. Scaling behaviour of the multiplicity distribution of Z=2 PFs has been checked. The emission angle of Z=2 PFs has been measured and pseudorapidity distributions for these PFs have been obtained. We observe that the value of momentum spread σ(p) for Z=2 PFs grows with increasing mass number of the projectile. The emission of Z=2 PFs is consistent with a single source with an excitation energy of about 8.9 MeV. The data has been compared with available data reported for lighter as well as heavier projectiles at the same and/or different energies.
Spin-Independent Relativistic Effect on Heavy Quarkonium Thermal Properties
Authors: Yu-Bing Dong
Published: September 2003

Spin-independent relativistic effect on binding and dissociation of heavy quarkonium in a thermal environment is stressed. The calculated result shows that the effect considerably influences the spin-averaged thermal properties of the system. As a result, it should be considered in future experiments at RHIC.
Charge Densities of the Nuclei 2O5Tl, 206,208Pb and the Occupancies of the Shell States
Authors: Gul'karov I. S. , Nigam B. P.
Published: September 2003

The charge densities of the nuclei 205Tl, 206,208Pb have been calculated in modified shell model with fractional number occupations of the shell states 2s, 2p, 2d, and 3s. The value of the n3 s was found to be 0.6 for 206TI, and ≈ 1 for 206,208Pb. These values differ appreciably from other data which range between 1.3 to 1.6. By addition of the two neutrons to 206P a charge of 0.24e of one proton is moved from the inner region of the 208Pb to the outer region. In the context of our modified shell model calculations, the measured charge density and occupancy profiles imply that the neutron degrees of freedom we employ carry charge.
Exact Dyson Expansion for a Single J-Shell Within the Quon Algebra
Authors: Avancini S. S. , Marinelli J. R. , Menezes D. P. , de Moraes M. M. Watanabe , Yoshinaga N.
Published: September 2003

The quon algebra, which interpolates between the Bose and Fermi algebras and depends on a free paramenter q, is used to generate a deformed Dyson boson expansion of the quadrupole operator. Then we obtain a quadrupole-quadrupole hamiltonian, for a single j-shell, in terms of this deformed bosonic operator. The hamiltonian is diagonalized and its eigenvalues are compared with the ones obtained from the fermionic quadrupole-quadrupole hamiltonian. The deformation parameter helps in achieving the correct excitation energy levels, what cannot be encountered in practice with the usual non-deformed Dyson expansion.
Neutron Separation Energies of Extremely Neutron Rich Excited Nuclei from Z=30 to 70
Authors: Rajasekaran M. , Aggarwal Mamta
Published: September 2003

Neutron rich nuclei in the medium mass region with thermal excitation and rotational energies, are investigated. A macroscopic-microscopic approach to reproduce the ground state separation energy combined with statistical approach for the excited rotating nuclei yields good results. Shell effects and shape transitions due to rotation alter the boundary of the drip line considerably at low temperatures and with increasing temperature the drip line is lowered to less neutron rich nuclei.
On the Elusiveness of ββ0ν Decay
Authors: Chan Tsan Ung
Published: September 2003

To date, no evidence of ββ0ν decay has been found despite tremendous experimental efforts. In contrast, ββ2ν decay has been clearly and definitely observed in several nuclei. These experimental facts question the reality of ββ0ν decay. This ββ0ν decay which violates lepton number conservation can only occur if the neutrino is massive and is its own antiparticle or in other words is a truly neutral particle. The observation of this decay implies then that the neutrino is a truly neutral particle and it has a non-zero mass. But the absence of ββ0ν decay implies only that at least one of the two necessary conditions is not fulfilled. Since the truly neutral character of neutrino is a necessary condition, it is important to provide objective criteria of truly neutral particles. We propose a generalized Gell-Mann and Nishijima formula which provides naturally the criteria of truly neutral particles. According to these criteria n and ν are different from their antiparticles for symmetric reason. The absence of ββ0ν decay could then be simply understood. Indeed a truly neutral particle could be more generally defined as a neutral particle with respect to all charges and is its own antiparticle. The Dirac character of the neutrino does not contradict any experimental fact.
On the Spinodal Instabilities at Subnuclear Densities
Authors: Ogul R.
Published: September 2003

We estimate the phase diagram for nuclear matter described by a Skyrme-type momentum dependent interaction and compare the results with that for a potential with no momentum dependence. It is shown that the momentum dependence decreases the critical temperatures.
Contributions of the Pion-Cloud to the Magnetic Moments of Nucleon Octet in a Relativistic Quark Model
Authors: Jena S. N. , Behera M. R. , Panda S.
Published: September 2003

The contributions of the pion-cloud to the magnetic moments of the nucleon octet is investigated in a chiral symmetric independent-quark model. The effective potential representing phenomenologically the confining interaction due to the non-perturbative multigluon mechanism is taken in the form [Formula: see text]. The pion-nucleon coupling constant [Formula: see text] comes out to be 14.43, as compared to the experimental value 14.1. The results obtained for the magnetic moments of the octet baryons, after incorporating the centre-of-mass motion and the low-order pionic corrections, agree reasonably with the experiment.
Effects of Mixed Velocity Distributions in One-Body Dissipation Theory
Authors: Abal G. , Donangelo R.
Published: September 2003

We derive an explicit expression for the one-body dissipation which includes effects from the mixing through the neck of the velocity distributions associated to each of the colliding nuclei. This expression may be considered a generalization of the window dissipation formula that covers the transition between the mononuclear and dinuclear regimes.
Nonlinear Waves of Nuclear Density
Authors: Kartavenko V. G. , Sãndulescu A. , Greiner W.
Published: September 2003

Nonlinear excitations of nuclear density are considered in the framework of semiclassical nonlinear nuclear hydrodynamics. Possible types of stationary nonlinear waves in nuclear media are analysed using Nonlinear Schrödinger equation of fifth order and classified using a simple mechanical picture. It is shown that a rich spectrum of nonlinear oscillations in one-dimensional nuclear medium exist.
Semimicroscopic Optical Potential with Effective Density-Dependent Nucleon-Nucleon Interaction
Authors: Kravchenko S. M. , Kuprikov V. I. , Soznik A. P.
Published: September 2003

An expression for the optical potential is obtained in the nuclear matter approximation while taking into account the rearrangement potential for the generalized two-particle density-dependent Skyrme forces. The rearrangement potential influence on the nucleon-nucleus scattering is investigated. It is shown that two- and three-particle Skyrme forces are not equivalent in calculating the imaginary part of the optical potential. The intensity of the optical potential (both its real and imaginary parts) appears to be decreased considerably when the rearrangement potential is taken into account. As a result the dependence of scattering phase shifts on the incident nucleons energy is changed markedly.
Information Entropy as a Measure of the Quality of a Nuclear Density Distribution
Authors: Lalazissis G. A. , Massen S. E. , Panos C. P. , Dimitrova S. S.
Published: September 2003

The information entropy of a nuclear density distribution is calculated for a number of nuclei. Various phenomenological models for the density distribution using different geometries are employed. Nuclear densities calculated within various microscopic mean field approaches are also employed. It turns out that the entropy increases from crude phenomenological models to more sophisticated (microscopic) ones. It is concluded that the larger the information entropy, the better the quality of the nuclear density distribution. An alternative approach is also examined: the net information content, i.e. the sum of information entropies in position and momentum space Sr+Sk. It is indicated that Sr+Sk is a maximum, when the best fit to experimental data of the density and momentum distributions is attained.
Model Study of Hot and Dense Baryonic Matter
Authors: Bhattacharyya Abhijit , Ghosh Sanjay K.
Published: September 2003

The properties of baryonic matter have been investigated at finite density and temperature using different models. The variation of baryon masses and fractional number densities with baryon density and temperature obtained from different models have been compared. The quark hadron phase transition have been studied using Chiral Colour Dieletric (CCD) model in the quark sector. No phase transition have been observed for the different variants of the Zimanyi-Moszkowski models below T=60 MeV.
Relativistic Quantum Kinetic Equation of the Vlasov Type for Systems with Internal Degrees of Freedom
Authors: Smolyansky S. A. , Prozorkevich A. V. , Schmidt S. , Blaschke D. , Röpke G. , Toneev V. D.
Published: September 2003

We present an approach to derive a relativistic kinetic equation of the Vlasov type. Our approach is especially reliable for the description of quantum field systems with many internal degrees of freedom. The method is based on the Heisenberg picture and leads to a kinetic equation which fulfills the conservation laws. We apply the approach to the standard Walecka Lagrangian and an effective chiral Lagrangian.
Classical and Quantal Chaos Described by a Fourth Order Quadrupole Boson Hamiltonian
Authors: Baran V. , Raduta A. A.
Published: September 2003

A quadrupole boson Hamiltonian is considered within a time dependent variational formalism. The trial functions are coherent states with respect to the quadrupole bosons [Formula: see text] and [Formula: see text]. The character, chaotic or regular, of the classical trajectories are studied, in terms of both the Poincaré surface of sections and maximal Lyapunov exponents, as a function of energy and an order parameter B, the coefficient of the third order boson term. A peculiar feature concerning the behavior of chaos and order in the range of large energies is pointed out. Quantizing the classical energy function one obtains an operator whose spectrum is analyzed in terms of level spacing distribution, Some classical and quantal features of the chaotic motion are possibly related.
Two Parameter Quantum Deformation of U(2) ⊃ U(1) Dynamical Symmetry and the Vibrational Spectra of Diatomic Molecules
Authors: Johal Ramandeep S. , Gupta Raj K.
Published: September 2003

The vibrational spectra in H2-molecule is studied by taking the two parameter quantum deformed Uqp(u2) ⊃ Uqp(u1) algebra as the model for the system. The results are improved, compared with the classical as well as the one parameter q-description. The fitting parameter remains the same (at most two) in both cases of q– and qp–deformations.
Nuclear Physics Methods for Problems in Relativistic Quantum Mechanics
Authors: Moshinsky Marcos , Riquer Verónica
Published: September 2003

Atomic and molecular physicists have developed extensive and detailed approximate methods for dealing with the relativistic versions of the Hamiltonians appearing in their fields. Nuclear physicists were originally more concerned with non-relativistic problems as the energies they were dealing with were normally small compared with the rest energy of the nucleon. This situation has changed with the appearance of the quark models of nucleons and thus the objective of this paper is to use the standard variational procedures of nuclear physics for problems in relativistic quantum mechanics. The 4 × 4α and β matrices in the Dirac equation are replaced by 2 × 2 matrices, one associated with ordinary spin and the other, which we call sign spin, is mathematically identical to the isospin of nuclear physics. The states on which our Hamiltonians will act will be the usual harmonic oscillator ones with ordinary and sign spin and the frequency ω of the oscillator will be our only variational parameter. The example discussed as an illustration will still be the Coulomb problem as the exact energies of the relativistic bound states are available for comparison. A gap of the order of 2mc2 is observed between states of positive and negative energy, that permits the former to be compared with the exact results.
Relativistic Finite-Volume Effect of Baryons and Phase Transition to the Quark-Gluon Plasma
Authors: Zhang Xiao-Bing , Zhang Qi-Ren
Published: September 2003

We compare a relativistic and thermodynamically consistent treatment for the finite-volume effect of baryons in the phase transition between hadronic matter and quark-gluon plasma, with the previous non-relativistic treatment. We find that, according to the relativistic theory, this phase transition is possible only when the baryonic spectrum is upper bounded.
Multiharmonic Nuclear Hamiltonian in the Region 120 < A ≤ 140
Authors: Giapitzakis J. , Ginis P. , Antonov A. N. , Massen S. E. , Anagnostatos G. S.
Published: September 2003

The isomorphic shell model is successfully applied for all the 30 stable nuclei with 50 < Z ≤ 58 and 70 < N ≤ 82 (i.e., with 120 < A ≤ 140). The model employs a multiharmonic Hamiltonian in contrast to single harmonic-oscillator Hamiltonian of the conventional shell model. Derived binding energies and charge radii are in very good agreements with the corresponding experimental values without using adjustable parameters.
A Simple Method for Estimating Temperatures in Central Nucleus-Nucleus Collisions: Application to Au + Au from 100 to 400 A MeV
Authors: Dželalija M. , Cindro N. , Basrak Z. , Čaplar R. , Korolija M. , Mishustin I.
Published: September 2003

Using a simple thermodynamic model based on the assumption of equilibrium in the colliding system, nuclear temperatures have been extracted from the data on central Au + Au collisions between 100 and 400 A MeV. The basic ingredients of the model are charged-particle and neutron multiplicities and the collective-flow energy.