Bergen Computational Physics Lab 3 Project Hosts (BCPL) Name Prof. Ph.D. Publ. # Citations U of B ISI ISI'02 Anderlik, Csaba 2001(+) Univ. of Bergen, 2001 6 51 Csernai, Laszlo P. 1987 Eotvos U. Budap. 1976 101 2116 Hansen, Jan-Petter 1999 Univ. of Bergen, 1990 56 470 (*) Hansteen, J. M. 1985($) Univ. of Bergen, 1976 27 1013 Helstrup, Haavard 2001(?) Univ. of Bergen, 1993 51 646 Kocbach, Ladislav 1993 Univ. of Bergen, 1977 39 974 Osnes, Eivind 1985(#) Univ. of Oslo, 1966 98 1088 Rohrich, Dieter 1999 Univ. of Marburg, 1986 72 1853 Stamnes, Jakob 1990 Univ. of Oslo, 1975 54 1039 Vaagen, Jan S. 1993 Univ. of Bergen, 1977 96 1248 (+) Senior Scientist ($) Professor emeritus (#) Prof. Univ. of Oslo (?) Prof. Bergen Univ. College (*) For JP Hansen citations that could not be traced back to the original by the ISI WoS trace program are not counted, because of the large number of citations (800+) to authors with the same name and initials.
Bergen Computational Physics Lab 4 BCPL Technical Review’02 - 14 yes of 14 questions: 100% result. Some comments: - Many institutions would like to have 92% of their users happy with what they provide and judging that the Lab is "extremely good and managed in an optimal way'. More importantly, users claim that they achieve their scientific goals and publications demonstrate that the achieved goals are of high scientific value. - 99% of users believe that they would not achieved the same results without the access to the infrastructure and all are thankful to the European Community for providing the scientific and financial support through the ARI programme. -The Bergen Computing Physics infrastructure is world-class in the topics of atomic, molecular, nuclear and particle reaction modeling. It combines parallel computer power and theoretical physicists and therefore offer an exceptional scientific environment to develop high quality research projects. -The quantity of access is 15% more than the foreseen number. This is justified by the change of computing facility : the Turbo Regatta supercomputer is faster than the previous machine.
6 Highlights of BCPL achievements in 2002 Since January 2000 up to now BCPL has received 55 project proposals has accepted 53 projects for EU support from the beginning of yr. 2000. So far, near to 100 researchers visited BCPL. Although we did not receive additional financing from the EU to cover the excess demand, we did accommodate 16.6% more visitors, than our first contract planned. We did not run out of EU financing: by saving on the expenses of the user meetings held at ECT* in Trento Italy, and taking advantage of our new IBM machine with 12.8 times increased power. As a consequence we managed to transfer 7.5% of our budget from the User Travel to the User Fee part, and so we stayed within the limits of our EU financing.
Bergen Computational Physics Lab 7 In year 2002 we hosted researchers for 19 projects, spreading over particle, high and low energy nuclear, atomic, plasma and molecular physics, and extending to related fields in astrophysics as well as abstract statistical physics problems for self avoiding walks and clusterization phenomena in sociological systems. Most projects belong to BCPL’s core activity of reaction modeling in different areas, 3-4 projects are related or abstract problems. A smaller part of the projects were continuing from the previous year. In this report only a fraction of the projects can be mentioned with important and recent results. The projects are grouped in thematic classes, as some of them are strongly related.
Bergen Computational Physics Lab 8 PARTICLE PHYSICS In the project “Three-body initial states in charmonium dissociation” (project no. 46) from Sylesian University, Czech Republic, led by P. Lichard, the main goal of the whole project was to calculate the contribution to the charmonium dissociation from the three-initial- meson reactions in a hadron gas. It was neccessary to determine the propagators and couplings of resonances before actual calculations of the reaction rates. During a short initial stay in Bergen the running masses of vector mesons, rho and Kstar, were determined by means of the dispersion relations. A good test in the rho meson case was a perfect agreement between the calculated and experimental value of the electromagnetic mean square radius of pion. It is well known that the usual fixed mass parametrization of the rho meson propagator badly fails in this test. This work will be utilized later to calculate possible hadronic background effects to the charmonium suppression in Quark-gluon Plasma.
Bergen Computational Physics Lab 9 HIGH ENERGY SUBATOMIC REACTIONS Projects 34-38, 44, addressed these reactions with microscopic transport models, while 29, 40, 43; used continuum or CFD approaches to evaluate the collective effects in these reactions. Project 29 was actually an important methodical advance, which introduced the use of different modules in a reaction model and established an exact physical interface among the modules. This enables later to create more involved modular reaction models, which can take advantage of GRID computing. Projects 34 and 36 worked on important parts of reaction models, on Meson-Nucleon Scattering (no. 34, KFKI, Budapest, by G. Wolf) and on Meson Production (no. 36, ELTE, Budapest, by G. Papp). The latter project has advanced considerably, so the results could e used for jet calculations in heavy ion reactions. The results obtained this way were published in two conference reports and in two papers.
Bergen Computational Physics Lab 10 The project “Event by Event Fluctuations in Heavy Ion Collisions” (project no. 35) led by S. Mrowczynski, of Soltan Institute, Warsaw, has addressed the question of how collective fluctuations may develop based on microscopic transport theoretical approaches: HIJING, FRITIOF and UrQMD. Many thousands of nucleon-nucleon and heavy ion collision events were generated in Bergen, which will be further analyzed statistically in Warsaw and Kielce in the near future. Project no. 37, led by A. Capella, Paris, France, used the Dual Parton Model to simulate heavy ion collisions and by analyzing the centrality dependence of multiplicity for RHIC collisions they addressed the question: can J/Psi suppression discriminate between deconfining- and comovers interaction models. A. Capella and D. Sousa have already submitted the first results for publication in Phys. Rev. C (nucl-th/0110072). In the second group of the projects in this energy range, project 40 investigated, different methods to analyze collective flow phenomena in heavy ion collisions. These phenomena are important because these flow phenomena are governed by the pressure, which on the other hand reflects directly the Equation of State of the high energy matter we are searching for. The project was led by J. Ollitraut, CEA, Saclay/Paris, France.
Bergen Computational Physics Lab 11 HIGH ENERGY SUBATOMIC REACTIONS contd. Two German projects, no. 38 and 44, led by A. Faessler, Tuebingen and F. Puelhofer, Marburg respectively, simulated heavy ion collisions by the QGSM and UrQMD models. These projects performed a comprehensive analysis of a large number of observables, which enables us to make a complex assessment of the experimental observations. Project 43 on “Relativistic Hydrodynamics for Heavy Ion Collisions” by H. Stoecker, & D. Strotman, Frankfurt, Germany, is a comprehensive model development work for extending the CFD approach to Ultra- relativistic, BNL - RHIC and CERN – LHC energies. Here already the possible Modular Modeling approach and possible task sharing is taken into consideration. Project 29, led by V. Magas, Lisbon, Portugal was working on the interface between the CFD module of the reaction simulation and of the so-called Freeze Out module. This module describes the stage of the reaction where mechanical, thermal and chemical equilibrium ceases to exist at the end of the reaction, and the final observables develop.
Bergen Computational Physics Lab 12 LOW & INTERMEDIATE ENERGY SUBATOMIC REACTIONS and ASTROPHYSICS Project 31 addressed the problem of modeling “Drip-line, Exotic Nuclei” led by M.V. Zhukov of Gothenburg, Sweden. To reveal the detailed Borromean halo excitation structure at least the four-body dynamics is necessary. At intermediate energies the Glauber or distorted wave (DW) impulse approximation can be applyed. The approaches contain as a main part the microscopic three-body structure of ground state, Glauber elastic scattering, DWIA charge-exchange reactions and the exact three-body continuum, complemented with DW approximation. A study of three intergated cross sections that leave the core (the alpha-particle) in the $^6$He projectile intact, has been performed. These cross sections are the diffractive, the one neutron stripping, and two neutrons stripping cross sections. Corresponding computer codes have been developed and a three-body ground state wave function of $^6$He has been used. The preliminary results are in a agreement with measured cross sections. Furthermore, in diffractive breakup of Borromean halo nuclei on proton the crucial role of the correlated continuum excitations in the fragment momentum distribution was demonstrated within a microscopic four-body DW theory.
Bergen Computational Physics Lab 13 ATOMIC PHYSICS In the project “Simulation software for laser-produced plasmas” (project no 48) led by Jiri Limpouch Czech Technical University in Prague, Czech Republic, simulations of intense short-pulse interaction using kinetic plasma simulation were performed, with a PIC code in order to get better understanding of fast electron acceleration under moderate laser intensities. Parallel computing is particularly needed when collisions are included as the algorithm modeling collisions, as this is time consuming and higher number of particles has to be taken into account than in collisionless case to reduce the additional statistical noise. Femtosecond laser-produced plasmas are bright, ultrafast line, x-ray sources, potentially suitable for different applications including material science and biology. The aims of the project are simulations of dynamics and especially atomic physics of the system. The calculated spectra are compared with experiment both to verify the code and to reveal the physics of the system in detail. The 1D time-resolved simulation of highly ionized plasma and for synthesis of the emitted K-shell spectra was improved, tested and used for the simulation of the experiments. Especial attention was paid for the synthesis of spectra emitted laterally in the recent foil and dot target experiments on Prague Asterix Laser System (PALS).
Bergen Computational Physics Lab 14 ATOMIC PHYSICS contd. The objective of project 47 on “Fragmentation in inelastic ion- molecule collisions” led by A. Dubois, Paris, is to use the skills of BCPL staff and to study non-perturbatively the electronic and fragmentation processes in an original and unified description of such systems, valid for low and intermediate impact energies. The project aims for * the dynamics of the electronic processes and the possible fragmentation of the molecule, and * the couplings between these two kinds of degrees of freedom, which may require a treatment beyond the Born-Oppeiheimer approximation. The project has developped two codes based on (i) a semiclassical coupled-channel approach to describe the dynamics of the electronic cloud and (ii) a quasiclassical method, especially devoted to the nuclear motion modeling. Compared to similar codes developed for ion-atom collisions, the use of these programs requires at least one order of magnitude more of CPU time and memory. One of the goals of the BCPL visit was related to the technical aspects of code optimisation, and more generally to the structure and planning of future computations.
Bergen Computational Physics Lab 15 ATOMIC PHYSICS contd. Project no. 21 “Electron transitions in atoms and molecules” led by L. Nagy, Cluj, Romania addressed the problems of: 1. Inner-shell excitation and two-electron transitions in atoms. 2. Ionization and fragmentation of fullerenes by charged particle impact. 3. One and two-electron transitions in the hydrogen molecule. Using the supercomputer at BCPL, the group has studied the inner-shell excitation of the lithium and the ionization-excitation of the helium by charged particle impact. The results for the second topic were published in J. Phys.B. In the calculations second-order perturbation theory was used. The inclusion of the two-step 1 mechanism in the calculations considerably improves previous results. The dependence of the cross sections on the sign of the projectile charge have been investigated. The ionization of the C60 by electron impact have been also studied. Cross sections have been calculated using a spherical model.
Bergen Computational Physics Lab 16 ASTROPHYSICS In project 42 on “Cooling of Extremely Compact Stars” led by Z. Stuchlik of Silesian University, Opava, Czech Republic, the study of neutron, quark, and hybrid stars was concentrated on diverse topics leading to the problem of cooling of extremely compact stars. The group worked with the preparation of a numerical code for cooling processes in extremely compact stars with realistic equations of state. They also considered hybrid stars with two-flavour quark cores, or three-flavour, strange quark cores, and discussed the possibility of a "cascade" evolution of a neutron star to a hybrid star with succesively two-flavour, and three-flavour quark cores as a result of accretion of matter onto the neutron star. For simplicity, the phase transition between the nuclear matter and the quark matter was considered to be of the first kind. A numerical code for selfgravitating polytropic and adiabatic fluid spheres taking into account the influence of a nonzero vacuum energy has been developed during our stay at BCPL. As a result of these and previous works a paper concerning the mixed influence of a nonzero vacuum energy (leading to both a repulsive or an attractive effective cosmological constant) and an electric charge on the character of black holes and naked singularities has been finished.
Bergen Computational Physics Lab 17 STATISTICAL PHYSICS Self avoiding walk (SAW) on a lattice is a widely used model of real polymer chain in a good solvent studied mostly by Monte Carlo techniques. SAW with incorporated interactions is a useful model of polymer chains even for solvents of poorer quality. In this project (no. 39) researchers led by Z. Limpuchova, have studied the asymptotic behavior of long chains in the latter case. Reliable estimation of model parameters (theta temperature and characteristic ratio) is important for setting up correct chain lengths and lattice parameters in other simulations that mimic behavior of real systems, for example copolymer micelles studied experimentally in our Laboratory of Specialty Polymers. This project developed a dynamic Monte Carlo method with pivot moves. A simple cubic lattice with interactions between nearest neighbors was used. The group checked that the results of the blocking method were compatible with integral autocorrelation times obtained by fast Fourier transform. The group has performed simulations up to a chain length of 4000 (in lattice units). Although, the researchers have used the available CPU time completely (more exactly we overused time limit by ca. 10%), linear asymptotic behavior was not reached. Thus, further simulations for even longer chains will be planned..
Bergen Computational Physics Lab 18 STATISTICAL PHYSICS contd. An interesting and very abstract idea is the base of project 45 by Z. Neda, of Cluj, Romania: “Statistical physics approach to clusterization phenomena in sociological systems”. The aim of the project was to study a spin-glass type frustrated model for coalition formation in sociological systems. Our main approach to this NP hard optimization problem leads through the classical methods of statistical physics using Monte Carlo optimizations. Two type of algorithms are used: (i) the classical simulated annealing method and (ii) the recently reported extremal optimization approach. Both methods are rather time-consuming, and high parallelization of the code is desired. Our results suggest that a globally coupled large system with +/- interactions between the elements, has two marginal behaviors. When the + links number dominate over the - links number in the optimal situation the system will clusterize in a single large cluster. When the - links number is bigger, the systems splits in as many clusters as many elements there are in the system. This transition resembles the one obtained in percolation type problems, and gives a hint that the model can be used effectively to study the so-called "social-percolation" problem too.
Bergen Computational Physics Lab 19 CONCLUSIONS of the SCIENTIFIC REPORT The selected projects give a taste of the variability of BCPL's research projects. Most projects were fully successful and achieved their goal. A few projects plan for a continuation. The offered computational power to EU-RI user groups is increased by a factor of 12.8 from the beginning of 2002 by installing an IBM e- server supercomputer (For the same access charge to the EU as before!). At the time of the installation it was the 6th most powerful supercomputer in Europe. We are preparing for the FP6 applications now. We apply as an individual RI for providing Transnational Access just as before but for more users (~40 man-months per year). In addition we participate in several I3, RI-network applications. We also apply for a Marie Curie Early Stage Training Site. In the Thematic programs under the IST and Nanotechnology and nanoscience subjects corresponding to our 3 Expressions of Interest submitted to the EU in June 2002.
Bergen Computational Physics Lab 21 I3HP / CSERNAI I3NS / VAAGEN I3Atom / HANSEN I3HPC / ANDERLIK BCPL plans for FP6/RI programme BCPL Single RI for offering Transnational Access I3 Member for: - Networking and - Joint Res. Projects [ RI rules would not allow for BCPL to provide access from four I3-s, while networking and JRP participation is OK.]
Bergen Computational Physics Lab 22 Other BCPL Proposals to EU Bergen-Nano-Phase NoE (N) / 6.03.03 /Csernai MC Early Stage Training Host /2.04.03 /Csernai/Voit BCPL Research Infrastr. / 15.04.03 /Csernai Bergen-Dist-Comp IP (IST) / 24.04.03 /Anderlik, D.R. Bergen-Heavy-Ion NoE (IST)/ Fall 03 /Anderlik, Csernai Participation: I3 activities 3-4 / Csernai, Vaagen, Hansen, Anderlik Participation: TIME (N) / coordinated by F. Shauer (CZ) / Anderlik, Csernai ???