Multifragmentation: Surface and Coulomb instabilities of sheets, bubbles, and donuts
International Nuclear Information System (INIS)
Moretto, L.G.; Tso, Kin; Wozniak, G.J.
1993-08-01
Disks, bubbles, and donuts have been observed in dynamical calculations of heavy ion collisions. These shapes are subject to a variety of surface and Coulomb instabilities. These instabilities are identified and analyzed in terms of their relevance to multifragmentation
Indian Academy of Sciences (India)
First page Back Continue Last page Overview Graphics. Conclusion. Problems of an Under-developed Economy. Geographical Location. Terrain. Change in attitude of mainstream India required. Using Technology to overcome problems.
Indian Academy of Sciences (India)
First page Back Continue Last page Overview Graphics. Conclusions. Be it 2G or 4G, networks are vulnerable to unwanted access and thus should be protected. 4G networks would be more sensitive as its core network will be TCP/IP based. Accordingly, resource and security management schemes with seamless ...
Indian Academy of Sciences (India)
First page Back Continue Last page Overview Graphics. Conclusions. Climate change is likely to reduce yields of most crops in long-term. In short-term effects may be small. Increased climatic variability could, however, cause significant fluctuations in production even in short-term. In long-term better adapted varieties are ...
Indian Academy of Sciences (India)
First page Back Continue Last page Overview Graphics. CONCLUSIONS. The seed for diabetes and other NCDs is sowed in early life – “in utero”, infancy and early childhood. These phenomena must be addressed for optimal prevention of diabetes and other chronic diseases.
Indian Academy of Sciences (India)
First page Back Continue Last page Overview Graphics. Conclusions: Extended objects – “D-branes” – appear naturally in theories of strings. They manifest themselves as new types of physical particles in string models. They provide a powerful handle on the symmetries and dynamics of strings. Branes will play a key role ...
Indian Academy of Sciences (India)
First page Back Continue Last page Overview Graphics. Conclusions : No dramatic difference in the dynamics of anion-water and water-water hydrogen bonds are found for Cl- and Br- ions. Solvation shells of these ions are not rigid. For OH- in water, HB dynamics in the hydration shell determines the rate of proton transfer.
DEFF Research Database (Denmark)
Sandøy, Helge; Kristiansen, Tore
2010-01-01
1. Comparing empirical findings with the “mountain peak model” In the introduction to this volume, we presented a “mountain peak model” of Nordic purism based on evidence showing that language scholars and lay people are very much in agreement as to where we find the more purist languages......-speaking Finland to Finnish-speaking Finland. In this conclusion to the volume, we will summarize the empirical findings presented in the volume, findings for use and attitudes alike, and compare them with the mountain peak model. That way, we may be able to estimate the nature of the cross-national ideological...
Coulomb-gas representation on higher-genus surfaces
International Nuclear Information System (INIS)
Bagger, J.; Goulian, M.
1990-01-01
In this paper we use the Coulomb-gas approach to construct the minimal-model conformal blocks on higher-genus Riemann surfaces. We define the higher-genus blocks by sewing, and write them in terms of the rational blocks of a compactified scalar field. We show that spurious states decouple, which implies that the blocks degenerate correctly. As an example, we compute the genus-two partition function, and verify modular invariance for the subset of minimal models which only require one type of screening charge. (orig.)
Surface effects on ionic Coulomb blockade in nanometer-size pores
Tanaka, Hiroya; Iizuka, Hideo; Pershin, Yuriy V.; Di Ventra, Massimiliano
2018-01-01
Ionic Coulomb blockade in nanopores is a phenomenon that shares some similarities but also differences with its electronic counterpart. Here, we investigate this phenomenon extensively using all-atom molecular dynamics of ionic transport through nanopores of about one nanometer in diameter and up to several nanometers in length. Our goal is to better understand the role of atomic roughness and structure of the pore walls in the ionic Coulomb blockade. Our numerical results reveal the following general trends. First, the nanopore selectivity changes with its diameter, and the nanopore position in the membrane influences the current strength. Second, the ionic transport through the nanopore takes place in a hopping-like fashion over a set of discretized states caused by local electric fields due to membrane atoms. In some cases, this creates a slow-varying ‘crystal-like’ structure of ions inside the nanopore. Third, while at a given voltage, the resistance of the nanopore depends on its length, the slope of this dependence appears to be independent of the molarity of ions. An effective kinetic model that captures the ionic Coulomb blockade behavior observed in MD simulations is formulated.
Directory of Open Access Journals (Sweden)
Conrad Markus
2015-01-01
Full Text Available Numerical simulations have been performed with a commercial distributed explicit FE-solver and the results have been compared with experiments. High explosive was placed in front of different concrete slabs with the dimension 100 × 100 × 16 cm. Some of the results of the simulations, in particular the profile of the craters, are not in agreement with the test results. Therefore the key characteristics of the constitutive equation based on Mohr-Coulomb yield surfaces and a damage evolution linked to the plastic strain has been reviewed.
Rijtema, P.E.
1979-01-01
Publikatie die bestaat uit twee delen: 1. General survey of the relation between water quantity and water quality; 2. Conclusions with regard to the connection of water quantity and water quality studies of surface waters
Shirley, Britt M.; Wooldridge, Barbara Ross; Camp, Kerri M.
2012-01-01
Jen Harrington is the owner and pastry chef of Sweet Conclusion, a bakery in Tampa, Florida. Most of Harrington's business comes from baking wedding cakes, but she has been attempting to attract customers to her retail bakery, where she sells cupcakes, pies, ice cream, and coffee. Nearly four years she opened Sweet Conclusion, the retail part of…
International Nuclear Information System (INIS)
Tubiana, M.
1993-01-01
In conclusion, a general consensus of a number of points which the author endeavours to summarize in this article: -doctors are an excellent channel for passing on information to the public -doctors feel that they do not know enough about the subject and a training on radiobiology and radiation protection is a necessity for them -communication between doctors and the general public is poor in this field -research should be encouraged in numerous areas such as: carcinogenic effect of low doses of radiation, pedagogy and risk perception
Coulombic Fluids Bulk and Interfaces
Freyland, Werner
2011-01-01
Ionic liquids have attracted considerable interest in recent years. In this book the bulk and interfacial physico-chemical characteristics of various fluid systems dominated by Coulomb interactions are treated which includes molten salts, ionic liquids as well as metal-molten salt mixtures and expanded fluid metals. Of particular interest is the comparison of the different systems. Topics in the bulk phase concern the microscopic structure, the phase behaviour and critical phenomena, and the metal-nonmetal transition. Interfacial phenomena include wetting transitions, electrowetting, surface freezing, and the electrified ionic liquid/ electrode interface. With regard to the latter 2D and 3D electrochemical phase formation of metals and semi-conductors on the nanometer scale is described for a number of selected examples. The basic concepts and various experimental methods are introduced making the book suitable for both graduate students and researchers interested in Coulombic fluids.
Francisco Sánchez-Royo, Juan
2012-12-01
The two-dimensional conducting properties of the Si(111) \\sqrt {3} \\times \\sqrt {3} surface doped by the charge surface transfer mechanism have been calculated in the frame of a semiclassical Drude-Boltzmann model considering donor scattering mechanisms. To perform these calculations, the required values of the carrier effective mass were extracted from reported angle-resolved photoemission results. The calculated doping dependence of the surface conductance reproduces experimental results reported and reveals an intricate metallization process driven by disorder and assisted by interband interactions. The system should behave as an insulator even at relatively low doping due to disorder. However, when doping increases, the system achieves to attenuate the inherent localization effects introduced by disorder and to conduct by percolation. The mechanism found by the system to conduct appears to be connected with the increasing of the carrier effective mass observed with doping, which seems to be caused by interband interactions involving the conducting band and deeper ones. This mass enhancement reduces the donor Bohr radius and, consequently, promotes the screening ability of the donor potential by the electron gas.
Coulomb Blockade Plasmonic Switch.
Xiang, Dao; Wu, Jian; Gordon, Reuven
2017-04-12
Tunnel resistance can be modulated with bias via the Coulomb blockade effect, which gives a highly nonlinear response current. Here we investigate the optical response of a metal-insulator-nanoparticle-insulator-metal structure and show switching of a plasmonic gap from insulator to conductor via Coulomb blockade. By introducing a sufficiently large charging energy in the tunnelling gap, the Coulomb blockade allows for a conductor (tunneling) to insulator (capacitor) transition. The tunnelling electrons can be delocalized over the nanocapacitor again when a high energy penalty is added with bias. We demonstrate that this has a huge impact on the plasmonic resonance of a 0.51 nm tunneling gap with ∼70% change in normalized optical loss. Because this structure has a tiny capacitance, there is potential to harness the effect for high-speed switching.
International Nuclear Information System (INIS)
Tosi, M.P.
1989-03-01
Recent progress in the theory of liquid-solid coexistence as approached from the liquid phase in systems with Coulomb forces is reviewed. Main attention is given to (i) Wigner crystallization of the electron gas in the degenerate and classical limits, and (ii) localization of bond particles leading to freezing in a pseudoclassical liquid-state version of the bond-charge model for elemental semiconductors. These models serve to illustrate crystallization driven by pure Coulomb repulsions and crystallization resulting from the interplay of attraction and repulsions in multicomponent systems, respectively. (author). 29 refs, 4 figs
Relativistic Coulomb excitation
International Nuclear Information System (INIS)
Winther, A.; Alder, K.
1979-01-01
Coulomb excitation of both target and projectile in relativistic heavy ion collisions is evaluated including the lowest order correction for the deviation from a straight line trajectory. Explicit results for differential and total cross sections are given in the form of tables and figures. (Auth.)
Interatomic Coulombic decay in helium nanodroplets
DEFF Research Database (Denmark)
Shcherbinin, Mykola; Laforge, Aaron; Sharma, Vandana
2017-01-01
, or in the droplet interior. ICD at the surface gives rise to energetic He+ ions as previously observed for free He dimers. ICD deeper inside leads to the ejection of slow He+ ions due to Coulomb explosion delayed by elastic collisions with neighboring He atoms, and to the formation of Hek+ complexes....
Brachistochrone with Coulomb friction
Hayen, J.
2005-10-01
The classical brachistochrone is considered with the inclusion of a resistant force, which is due to Coulomb friction, in addition to the uniform gravitational force that is present. The solution to this problem is expressed in terms of standard functions, and it is developed in two separate ways by means of constrained variational calculus methods. These ways involve formulations of the problem in terms of temporal and spatial independent variables, respectively. The equations of motion that result in both cases are non-linear and coupled. The utilization of path variables is a central feature of the developments provided.
Chaos near the Coulomb barrier. Nuclear molecules
International Nuclear Information System (INIS)
Strayer, M.R.
1984-01-01
The present work examines in detail the classical behavior of the α + 14 C and the 12 C + 12 C(O + ) collison at energies near the Coulomb barrier. The long-time motion of the compound nuclear system is identified in terms of its classical quasiperiodic and chaotic behavior. The consequences of this motion are discussed and interpreted in terms of the evolution of the system along a dynamical energy surface. 45 references
Coulomb-oscillator duality and 5-dimensional Coulomb problem
Karayan, K H
2003-01-01
It is shown that the Hurwitz transformation connects the eight-dimensional oscillator problem with the five-dimensional Coulomb problem. The hyperspherical and parabolic coordinates are applied for analyzing the five-dimensional Coulomb problem. We calculate the spherical and parabolic bases for this system, derive the Park's and Tarter's representations for the coefficients of the spherical-parabolic and parabolic-spherical interbasis expansions
Diriken, J; Balabanski, D; Blasi, N; Blazhev, A; Bree, N; Cederkäll, J; Cocolios, T E; Davinson, T; Eberth, J; Ekström, A; Fedorov, D V; Fedosseev, V N; Fraille, L M; Franchoo, S; Georgiev, G; Gladnishki, K; Huyse, M; Ivanov, O V; Ivanov, V S; Iwanicki, V; Jolie, J; Konstantinopoulos, T; Kröll, Th; Krücken, R; Köster, U; Lagoyannis, A; Bianco, G Lo; Maierbeck, P; March, B A; Napiarkowski, P; Patronis, N; Pauwels, D; Reiter, P; Seliverstov, M; Sletten, G; Van de Walle, J; Van Duppen, P; Voulot, D; Walters, W B; Warr, N; Wenander, F; Wrzosek, K
2010-01-01
The B(E2; Ii ! If ) values for transitions in 71Ga and 73Ga were deduced from a Coulomb excitation experiment at the safe energy of 2.95 MeV/nucleon using post-accelerated beams of 71,73Ga at the REX-ISOLDE on-line isotope mass separator facility. The emitted gamma rays were detected by the MINIBALL-detector array and B(E2; Ii->If ) values were obtained from the yields normalized to the known strength of the 2+ -> 0+ transition in the 120Sn target. The comparison of these new results with the data of less neutron-rich gallium isotopes shows a shift of the E2 collectivity towards lower excitation energy when adding neutrons beyond N = 40. This supports conclusions from previous studies of the gallium isotopes which indicated a structural change in this isotopical chain between N = 40 and N = 42. Combined with recent measurements from collinear laser spectroscopy showing a 1/2- spin and parity for the ground state, the extracted results revealed evidence for a 1/2-; 3/2- doublet near the ground state in 73 31Ga...
Conclusions and recommendations
International Nuclear Information System (INIS)
1984-01-01
The FAO/IAEA/GSF/SIDA Co-ordinated Research Programme on Cereal Grain Protein Improvement by Nuclear Techniques was a follow-up to the FAO/IAEA/GSF Co-ordinated Research Programme on the Use of Nuclear Techniques for Seed Protein Improvement. It was initiated in 1969 and ended in 1981. The objectives of the meeting were to review and evaluate the achievements of the current and previous programmes in order to draw conclusions on the possibility of genetic improvement of cereal grain protein using nuclear techniques, to identify unsolved problems and to discuss and propose possible approaches for their solution. Through reviews and discussions, conclusions and recommendations were made by the participants
Radiative capture versus Coulomb dissociation
International Nuclear Information System (INIS)
Esbensen, H.; Physics
2006-01-01
Measurements of the Coulomb dissociation of 8 B have been used to infer the rate of the inverse radiative proton capture on 7 Be. The analysis is usually based on the assumptions that the two processes are related by detailed balance and described by E1 transitions. However, there are corrections to this relation. The Coulomb form factors for the two processes, for example, are not identical. There are also E2 transitions and higher-order effects in the Coulomb dissociation, and the nuclear induced breakup cannot always be ignored. While adding first-order E2 transitions enhances the decay energy spectrum, the other mechanisms cause a suppression at low relative energies. The net result may accidentally be close to the conventional first-order E1 calculation, but there are differences which cannot be ignored if accuracies of 10% or better are needed
Radiative Capture versus Coulomb Dissociation
International Nuclear Information System (INIS)
Esbensen, Henning
2006-01-01
Measurements of the Coulomb dissociation of 8B have been used to infer the rate of the inverse radiative proton capture on 7Be. The analysis is usually based on the assumptions that the two processes are related by detailed balance and described by E1 transitions. However, there are corrections to this relation. The Coulomb form factors for the two processes, for example, are not identical. There are also E2 transitions and higher-order effects in the Coulomb dissociation, and the nuclear induced breakup cannot always be ignored. While adding first-order E2 transitions enhances the decay energy spectrum, the other mechanisms cause a suppression at low relative energies. The net result may accidentally be close to the conventional first-order E1 calculation, but there are differences which cannot be ignored if accuracies of 10% or better are needed
Coulomb drag in multiwall armchair carbon nanotubes
DEFF Research Database (Denmark)
Lunde, A.M.; Jauho, Antti-Pekka
2004-01-01
We calculate the transresistivity rho(21) between two concentric armchair nanotubes in a diffusive multiwall carbon nanotube as a function of temperature T and Fermi level epsilon(F). We approximate the tight-binding band structure by two crossing bands with a linear dispersion near the Fermi...... surface. The cylindrical geometry of the nanotubes and the different parities of the Bloch states are accounted for in the evaluation of the effective Coulomb interaction between charges in the concentric nanotubes. We find a broad peak in rho(21) as a function of temperature at roughly T similar to 0.4T...
International Nuclear Information System (INIS)
Brandao, S.B.
1987-01-01
The level structure of 189 Os has been studied by Coulomb excitation using 35 Cl, 28 Si, 16 O beams. GOSIA, a code written to analyze multiple Coulomb excitation, was used to obtain the reduced probabilities of transition B(E2). The results for interband and intraband turned out possible the classification of the states following Nilsson levels. Gamma-rays originating from deexcitation of 216.7 and 219.4 keV have been separated and the reduced probability of transition has been measured. (A.C.A.S.) [pt
Conclusion of safety evaluation
International Nuclear Information System (INIS)
Pedersen, A.
1982-01-01
Results of the salt deposit safety evaluation are compared with a proposed set of Danish general criteria for high-level waste disposal prepared by the Danish environmental agency. There are three main criteria: 1. Natural transport mechanisms should not give pollution which is impermissible according to present regulations. The here referred investigations confirmed that the situations considered will not even destroy the steel contaners around the waste. 2. Violent natural phenomena should not give releases which result in a health risk to the population which is significant compared to other man-made and natural risks. No relevant natural event or major geological change which might destroy the steel containers around the waste was found. 3. The probability of future human intrusion into the repository should be small, and the ensuing health risk to the population should be negligible compared to other man-made risks. We have not directly quantified the probability of intrusion. But it has to be very small. In North Jutland there are at least 10 salt domes with the salt mirror closer to the surface than Mors. They represent an area of 500 x 10 6 m 2 . The releases we have found for the human intrusion cases result in dose rates ranging from nothing to 1/2 rem/year. The health effects of such dose rates are extremely small and the health risk accordingly negligible. (EG)
International Nuclear Information System (INIS)
2013-01-01
This section summarizes the presentations and Panel discussions of the 4 technical sessions of the workshop: 1 - Regulatory cooperation on generic and design specific issues, MDEP working groups (EPR, AP1000), vendor inspection co-operation, digital I and C, and codes and standards (7 presentations); 2 - Regulatory positions on siting practices and enhancements as a result of lessons learned from Fukushima accident (5 presentations); 3 - Construction experience and regulatory oversight of new reactor construction activities (6 presentations); 4 - Lessons learned from regulatory licensing reviews of new reactor designs (6 presentations). The main workshop conclusions are listed as follows: - Harmonization is a long term goal and significant progress has been made. However, this long term objective needs to be associated with short term measurable steps; - MDEP approach to tackle on one side with specific technical subjects, and to strive harmonisation on generic topics was considered appropriate; - Convergence on technical requirements is more realistic than harmonization of codes and standard; - Beneficial early engagement of different stakeholders specially at the siting stage has been acknowledged; - Need to characterise the hazards and to keep updated the safety assessment (PSR); - Land use issues are important particularly after Fukushima; - Commissioning aspects (e.g. training aspects for inspectors) should be addressed by WGRNR taking into account MDEP interaction; - Importance of WGRNR ConEx Programme: construction experience sharing is a leverage for quality and so for a future safe operation of NPPs; - Capability of licensee to follow the responsibility of design changes (could be an issue for small utilities); - Importance of Periodic Safety Reviews to review and account for the design. Finally, the WGRNR has convened that a third conference should be held in about two years time (2014- 2015)
International Nuclear Information System (INIS)
2011-01-01
authorities, reactor designers, and operators/ licensees perspectives on the various practices used in the regulation of nuclear power plant siting (selection, evaluation and site preparation). This session was also aimed to address issues on sites where a mixture of activities are taking place (e.g., operating units, new construction, decommissioning, etc.) including organisation of the regulators and licensee/engineering organisation, methods, systems, etc. Conclusions: In general workshop participants agreed on the need to regularly have these kind of forums to discuss relevant regulatory issues for new builds. One important aspect of this workshop was the participation of 'New Entrants'. The interaction between NEA member countries with mature nuclear power plants and newcomers was quite important since it gave newcomers the possibility to benefit of mature international practices in order to focus their regulatory oversight and control. NEA members could also benefit from insights the New Entrants discover as they develop or enhance their regulatory controls. In addition technical exchanges associated with construction experience of New Entrants as they begin to license, build and operate NPP could benefit NEA members
Energy Technology Data Exchange (ETDEWEB)
Bauer, H.
1998-12-31
The scattering system {sup 162}Dy {yields} {sup 116}Sn has been examined at energies in the vicinity of the Coulomb barrier using the Heidelberg-Darmstadt Crystal Ball spectrometer combined with 5 Germanium-CLUSTER detectors. In order to study pairing correlations as a function of angular momentum cold events were selected in the 2n stripping channel by identifying and suppressing the dominant hot part of the transfer with the Crystal Ball. The CLUSTER detectors with their high {gamma}-efficiency were used to identify the transfer channel and to resolve individual final states. Cross sections for the population of individual yrast states in a cold transfer reaction have been measured for the first time indicating the strong influence of higher transfer multipolarities. At small surface distances Coulomb-nuclear interferences were found to be responsible for the stronger decline of the population of higher yrast states in the transfer channel as compared to the Coulex channel. As a preparatory study for 2n transfer measurements between high spin yrast states in the backbending region of deformed nuclei the Coulomb excitation process in the crossing region of two bands in {sup 162}Dy has been analyzed. The gross properties of the measured population probabilities could be interpreted in a simple band mixing model. (orig.)
Walraven, van K.; Walraven, van K.
1998-01-01
This volume is the result of an international symposium on early warning and conflict prevention, held in The Hague in 1996. Two chapters deal with Africa. They investigate the role regional organizations - whether intergovernmental, State or non-State - can play in the prevention of conflicts in
David L. Peterson; James M. Vose
2012-01-01
Forest ecosystems in the United States in the year 2100 will differ from those of today as a result of a changing climate. Those differences will be superimposed on the human imprint of forest management and the legacies of other land use activities, stressors, and disturbances of the 19th and 20th centuries. Future changes in forest ecosystems will occur across both...
Dagenais, Daniel
2015-01-01
La sociologie contemporaine de la famille se contente souvent de montrer l’influence de tel ou tel aspect de la « société » sur la famille. Elle se donne par là un objet substantiel, influencé de l’extérieur de lui-même par la société. Cet ouvrage défend une sociologie où le type de famille est organiquement lié à un type de société. En ce sens, il serait plus exact de dire qu’il a porté sur les changements de la société moderne appréhendés depuis un objet particulier : la famille. Non seulem...
DEFF Research Database (Denmark)
Warming, Hanne; Fahnøe, Kristian
2017-01-01
analysis approach reveal how clients’ struggles in intimate and societal life, and in public and private spaces, are intertwined with geo-politics and global flows of governance strategies, e.g. neoliberalism and managerialism, which also condition social work practices. Indeed, social work constitutes......Warming and Fahnøe provide a cogent overview of how a lived citizenship approach enables critical analyses of social work and social policies by addressing challenges related to rights, recognition, participation, belonging and identity. The sub-concept of intimate citizenship and a spatial...
International Nuclear Information System (INIS)
2001-01-01
The obtained during examination results allowing to thinking that at under realization the works with substances containing in its content the fibre-genic and toxic components it is possible application of probucol or other antioxidants with analogous features. The probucol efficiency, proven in the work, is experimental ground for application of this antioxidant in the clinic of occupational pathology with medical and prophylactic purpose
Mallon, Isabelle
2015-01-01
Le maintien de l’identité en maison de retraite procède d’un travail actif des personnes âgées, pour prévenir le vieillissement ou s’adapter à ses conséquences. La lutte contre le temps qui passe et qui menace de creuser un écart entre soi et soi-même exige des efforts, un véritable travail du vieillir. Rien n’est moins évident que de continuer à raconter une histoire qui rende cohérentes des dimensions de l’identité remises en cause par l’avancée en âge, qui transforme non seulement la perso...
Guibet-Lafaye, Caroline
2013-01-01
L’ensemble de ces analyses a permis de montrer que « le bonheur n’est ni une course effrénée au toujours plus et toujours tournée vers l’avenir, ni l’unique nostalgie du passé » (Proust) pas plus qu’il n’est la simple somme des plaisirs de la vie à laquelle seraient soustraits les maux subis. Le bonheur est bien plutôt un état – c’est-à-dire pas seulement un sentiment – de bien-être dépendant d’une pluralité de facteurs. Selon la perspective à partir de laquelle on l’appréhende (la psychologi...
International Nuclear Information System (INIS)
Kimsanov, B.Kh.; Karimov, M.B.
1998-01-01
Organic synthesis with using glycerin and its many derivatives is a very perspective direction of organic chemistry. From all worded material of this monograph follow that on base of this class of compounds it is practically possible to receive not only polyfunctional aliphatic organic substances but this is a big perspective of synthesis of vast row of new heterocyclic products
Indian Academy of Sciences (India)
... and thus should be protected. 4G networks would be more sensitive as its core network will be TCP/IP based. Accordingly, resource and security management schemes with seamless connectivity would emerge as open research topics. It means we would be entering into a 'secure wireless multimedia society' this century.
Indian Academy of Sciences (India)
Microbial organisms play a major role in assimilation of P from the water column and also from the interstitial waters. Mineralisation of microbial bodies is a very rapid process and autophosphatization may occur within few hours or days after death. Geo-microbiology is an important subject and needs to be developed.
International Nuclear Information System (INIS)
2000-01-01
In the monograph peculiarities of radioinduced sexual dysfunctions of Chernobyl accident liquidators are described. It is shown, that ones of principal clinical manifestations of stochastic radio-genetic effects are sexual dysfunctions. Assessment in point of view of stages and components of copulative cycle is carried out. Authors made attempt to take in account all involved in sexual dysfunctions systems for examined contingent. It is noted, that genesis of radioinduced sexual dysfunctions is complex and it includes both the influence of vegetative nervous system damage and the direct damage of gonads. During clinical examination with patients it is revealed that both vegetative-vascular dysfunctions and asteno-neurotic dysfunctions are dominating. Authors noting that mentioned sexual dysfunctions are caused by low dose irradiation, and they have certain distinctions. Measures for comprehensive rehabilitation of suffered contingent in late period after irradiation are developed
Indian Academy of Sciences (India)
CT positions alter after DNA damage and are intrinsically coupled to the ability of cells to elicit a damage response dependent on ATM/ATR and DNA-PKcs activities. Repositioned CTs revert to their original neighborhoods in a repair dependent manner and perhaps requires mitotic 'resetting”. Thus, CT reorganization could ...
Indian Academy of Sciences (India)
Confounding effect of obesity and associated co-morbidities (especially on metabolic abnormalities, cardiovascular and cerebrovascular morbidity) should be clearly dissected out in future studies ...
Arnold, Steven M.; Wong, Terry T.
2011-01-01
This compilation of papers in this book represents approximately half of the works discussed at the MS&T 2010 symposium entitled Tools, Models, Databases, and Simulation Tools Developed and Needed to Realize the Vision of Integrated Computational Materials Engineering at Materials Science & Technology wherein five sessions comprised of 33 presentations was organized. The goal of the symposium was two fold To provide a forum in which current state-of-the-art methods for ICME (e.g., information informatics, experimentation, and modeling) could be openly discussed and critiqued by not only materials scientist but also structural engineers/researchers, component designers, industrial leaders and government program managers. To leave the symposium and in particular the panel discussion with a clear idea of the gaps and barriers (both technical, cultural and economical) that must be addressed in order for ICME to fully succeed. The organizers felt that these goals were met, as particularly evident by the standing room only attendance during a lively panel discussion session at the end of the Symposium. However it is the firm belief of the editors of this book that this symposium was merely a start in the right direction, and that subsequent conferences/symposium (e.g., First World Congress on Integrated Computational Materials Engineering to be held July 10-14, 2011 at Seven Springs Mountain Resort in Pennsylvania) must work hard to ensure that a truly diverse, multidisciplinary, community of researchers and practitioners are present and have ample opportunity for interaction. This will ensure that a proper balance between push and pull disciplines and technologies is maintained so that this emerging focus area, Integrated Computational Materials Engineering (ICME), has the greatest potential for success and impact on "system-level" payoffs. Similarly, a pro-active approach is required to reform historical modes of operation in industry, government and the academic sectors so as to facilitate multidisciplinary collaboration and to clearly articulate the vision and scope of ICME.
Indian Academy of Sciences (India)
First page Back Continue Last page Overview Graphics. First study on fHSC. First study on fHSC. fHSC exhibit embryonic stem cell like properties. fHSC therapy results in myocardial regeneration in rat model of MI. fHSC may be a novel stem cell type for cardiovascular regeneration.
Indian Academy of Sciences (India)
Climate change is likely to reduce yields of most crops in long-term. In short-term effects may be small. Increased climatic variability could, however, cause significant fluctuations in production even in short-term.
DEFF Research Database (Denmark)
de Vreese, Claes; Reinemann, Carsten; Esser, Frank
2017-01-01
At the outset, we asked if there is any good news about the news and, if so, where the good news is. In academic research and public discussions about news and democracy, one fi nds different interpretations of the state of current news provision. A tendency towards pessimism about current news...... is seen as having a negative impact on the quality of political life and democracy. Set against the pessimism and caution in the public debate and literature on news quality and the performance of political journalism, we were not optimistic that we would fi nd good-quality news or that we would be able...... to offer some good news as a positive antidote, so to speak, to the pervasive pessimism in the literature....
DEFF Research Database (Denmark)
Hadfield, Amelia; Whitman, Richard; Manners, Ian James
2017-01-01
The stakes have never been higher for the European Union. Its very distinctiveness – twenty-eight separate national units morphed into an inelegant but powerful overarching supranational institutional framework – now appear to have less, rather than more in common. Taken together, Member States......’ own quarrelsome attitudes, as well as external perceptions of EU actorness as materially diminished are in danger of eroding its overall foreign policy presence. EU crises have radiated geopolitically and deepened in severity, neither containable within Europe nor regarded as a ‘domestic’ issue...
International Nuclear Information System (INIS)
Ainul Hayati Daud; Hazmimi Kasim
2010-01-01
In Asia, Japan and the Republic of Korea have conducted similar studies but relying on statistical data and used inputs and outputs (I-O) methodology, utilizing on general macro-level data. In contrast, this study captures data directly through surveys using questionnaires, face-to-face interviews, case studies and focus group discussions. The impact of nuclear technology applications in Malaysia were evaluated both quantitatively and qualitatively. These impacts are then linked to a broader objective associated with technological development, namely wealth generation, knowledge generation and societal well-being. In the process of the study, users and practitioners of the technology highlighted issues and challenges faced by them. To cap the study, the level of activities of nuclear technology in Malaysia was benchmarked against those in Japan and the Republic of Korea. This chapter highlights the results of the study, the outcome of the study, followed by recommendations as response to issues and challenges raised by respondents, and finally the way forward for monitoring and charting further progress of nuclear technology in the country. (author)
DEFF Research Database (Denmark)
Jørgensen, Christian Helms; Wallo, Andreas; Toiviainen, Hanna
2015-01-01
production and knowledge-work offer growing learning opportunities to people throughout their active working life. In contrast to the stable and standardised modes of Fordist production, modern working life is characterised by rapid changes and employees interacting across globally distributed professional...... and obstacles to enhance learning through negotiation and boundary-crossing between different areas of expertise and professionalism. We are far from seeing rich learning environments provided to large groups of lowskilled workers in poor working conditions at the bottom of the global supplier chains. This book......Work in times of globalisation and uncertainty is undergoing considerable changes, which has strengthened the importance of work as a site of learning. New trends in production, such as digitalisation, challenge traditional modes of producing goods and services. Emerging forms of flexible...
Grignon, F.; Mazrui, A.; Rutten, M.M.E.M.; Rutten, M.M.E.M.; Mazrui, A.; Grignon, F.
2001-01-01
The outcome of a three-day conference held at the African Studies Centre, Leiden, The Netherlands, in September 1998, this book on the 1997 Kenya general elections is organized in four parts: the direct pre-electoral background; technical and national analysis of the general elections, including the
DEFF Research Database (Denmark)
Fahnøe, Kristian Relsted; Warming, Hanne
2017-01-01
analysis approach reveal how clients’ struggles in intimate and societal life, and in public and private spaces, are intertwined with geo-politics and global flows of governance strategies, e.g. neoliberalism and managerialism, which also condition social work practices. Indeed, social work constitutes......Fahnøe and Warming provide a cogent overview of how a lived citizenship approach enables critical analyses of social work and social policies by addressing challenges related to rights, recognition, participation, belonging and identity. The sub-concept of intimate citizenship and a spatial...... a kind of sociological magnifying glass through which broader social changes can be studied, including dynamics of inclusion and exclusion, new conflicts and modes of resistance, and new social pathologies....
Coulomb blockade induced by magnetic field
International Nuclear Information System (INIS)
Kusmartsev, F.V.
1992-01-01
In this paper, the authors found that a Coulomb blockade can be induced by magnetic field. The authors illustrated this effect on the example of a ring consisting of two and many Josephson junctions. For the ring with two junctions we present an exact solution. The transition into Coulomb blockade state on a ring transforms into a linear array of Josephson junctions, although in latter case the effect of magnetic field disappears. In the state of Coulomb blockade the magnetization may be both diamagnetic and paramagnetic. The Coulomb blockade may also be removed by external magnetic field
Coulomb dissociation of N-20,N-21
Roeder, Marko; Adachi, Tatsuya; Aksyutina, Yulia; Alcantara, Juan; Altstadt, Sebastian; Alvarez-Pol, Hector; Ashwood, Nicholas; Atar, Leyla; Aumann, Thomas; Avdeichikov, Vladimir; Barr, M.; Beceiro, Saul; Bemmerer, Daniel; Benlliure, Jose; Bertulani, Carlos; Boretzky, Konstanze; Borge, Maria J. G.; Burgunder, G.; Caamano, Manuel; Caesar, Christoph; Casarejos, Enrique; Catford, Wilton; Cederkall, Joakim; Chakraborty, S.; Chartier, Marielle; Chulkov, Leonid; Cortina-Gil, Dolores; Crespo, Raquel; Pramanik, Ushasi Datta; Diaz-Fernandez, Paloma; Dillmann, Iris; Elekes, Zoltan; Enders, Joachim; Ershova, Olga; Estrade, A.; Farinon, F.; Fraile, Luis M.; Freer, Martin; Freudenberger, M.; Fynbo, Hans; Galaviz, Daniel; Geissel, Hans; Gernhaeuser, Roman; Goebel, Kathrin; Golubev, Pavel; Diaz, D. Gonzalez; Hagdahl, Julius; Heftrich, Tanja; Heil, Michael; Heine, Marcel; Heinz, Andreas; Henriques, Ana; Holl, Matthias; Ickert, G.; Ignatov, Alexander; Jakobsson, Bo; Johansson, Hakan; Jonson, Bjorn; Kalantar-Nayestanaki, Nasser; Kanungo, Rituparna; Kelic-Heil, Aleksandra; Knoebel, Ronja; Kroell, Thorsten; Kruecken, Reiner; Kurcewicz, J.; Kurz, Nikolaus; Labiche, Marc; Langer, Christoph; Le Bleis, Tudi; Lemmon, Roy; Lepyoshkina, Olga; Lindberg, Simon; Machado, Jorge; Marganiec, Justyna; Mostazo Caro, Magdalena; Movsesyan, Alina; Najafi, Mohammad Ali; Nilsson, Thomas; Nociforo, Chiara; Panin, Valerii; Paschalis, Stefanos; Perea, Angel; Petri, Marina; Pietri, S.; Plag, Ralf; Prochazka, A.; Rahaman, Md. Anisur; Rastrepina, Ganna; Reifarth, Rene; Ribeiro, Guillermo; Ricciardi, M. Valentina; Rigollet, Catherine; Riisager, Karsten; Rossi, Dominic; del Rio Saez, Jose Sanchez; Savran, Deniz; Scheit, Heiko; Simon, Haik; Sorlin, Olivier; Stoica, V.; Streicher, Branislav; Taylor, Jon; Tengblad, Olof; Terashima, Satoru; Thies, Ronja; Togano, Yasuhiro; Uberseder, Ethan; Van de Walle, J.; Velho, Paulo; Volkov, Vasily; Wagner, Andreas; Wamers, Felix; Weick, Helmut; Weigand, Mario; Wheldon, Carl; Wilson, G.; Wimmer, Christine; Winfield, J. S.; Woods, Philip; Yakorev, Dmitry; Zhukov, Mikhail; Zilges, Andreas; Zuber, Kai
2016-01-01
Neutron-rich light nuclei and their reactions play an important role in the creation of chemical elements. Here, data from a Coulomb dissociation experiment on N-20,N-21 are reported. Relativistic N-20,N-21 ions impinged on a lead target and the Coulomb dissociation cross section was determined in a
Strongly coupled dust coulomb clusters
International Nuclear Information System (INIS)
Juan Wentau; Lai Yingju; Chen Mingheng; I Lin
1999-01-01
The structures and motions of quasi-2-dimensional strongly coupled dust Coulomb clusters with particle number N from few to hundreds in a cylindrical rf plasma trap are studied and compared with the results from the molecular dynamic simulation using more ideal models. Shell structures with periodic packing in different shells and intershell rotational motion dominated excitations are observed at small N. As N increases, the boundary has less effect, the system recovers to the triangular lattice with isotropic vortex type cooperative excitations similar to an infinite N system except the outer shell region. The above generic behaviors are mainly determined by the system symmetry and agree with the simulation results. The detailed interaction form causes minor effect such as the fine structure of packing
Scattering of an ion beam by charged fine particles with Coulomb force
International Nuclear Information System (INIS)
Amemiya, H.; Nakamura, Y.
2002-01-01
Fine particles satisfying critical limits act as Coulomb forces and scatter charged particles like beams due to the long-range force. Otherwise, fine particles behave as tiny probes. The energy loss and broadening rates of an ion beam by particles having Coulomb fields are investigated where the Coulomb logarithm is taken as a variable. Dependence of the energy loss and broadening on the plasma density, dust charge and beam energy is obtained. A method for measuring the dust surface charge is also given
Coulomb repulsion in short polypeptides.
Norouzy, Amir; Assaf, Khaleel I; Zhang, Shuai; Jacob, Maik H; Nau, Werner M
2015-01-08
Coulomb repulsion between like-charged side chains is presently viewed as a major force that impacts the biological activity of intrinsically disordered polypeptides (IDPs) by determining their spatial dimensions. We investigated short synthetic models of IDPs, purely composed of ionizable amino acid residues and therefore expected to display an extreme structural and dynamic response to pH variation. Two synergistic, custom-made, time-resolved fluorescence methods were applied in tandem to study the structure and dynamics of the acidic and basic hexapeptides Asp6, Glu6, Arg6, Lys6, and His6 between pH 1 and 12. (i) End-to-end distances were obtained from the short-distance Förster resonance energy transfer (sdFRET) from N-terminal 5-fluoro-l-tryptophan (FTrp) to C-terminal Dbo. (ii) End-to-end collision rates were obtained for the same peptides from the collision-induced fluorescence quenching (CIFQ) of Dbo by FTrp. Unexpectedly, the very high increase of charge density at elevated pH had no dynamical or conformational consequence in the anionic chains, neither in the absence nor in the presence of salt, in conflict with the common view and in partial conflict with accompanying molecular dynamics simulations. In contrast, the cationic peptides responded to ionization but with surprising patterns that mirrored the rich individual characteristics of each side chain type. The contrasting results had to be interpreted, by considering salt screening experiments, N-terminal acetylation, and simulations, in terms of an interplay of local dielectric constant and peptide-length dependent side chain charge-charge repulsion, side chain functional group solvation, N-terminal and side chain charge-charge repulsion, and side chain-side chain as well as side chain-backbone interactions. The common picture that emerged is that Coulomb repulsion between water-solvated side chains is efficiently quenched in short peptides as long as side chains are not in direct contact with each
Selfconsistent theory of Coulomb mixing in nuclei
International Nuclear Information System (INIS)
Pyatov, N.I.
1978-01-01
The theory of isobaric states is considered according to the Coulomb mixing in nuclei. For a given form of the isovestor potential the separable residual interactions are constructed by means of the isotopic invariance principle. The strength parameter of the force is found from a selfconsistency condition. The charge dependent force is represented by the Coulomb effective potential. The theory of the isobaric states is developed using the random phase approximation. The Coulomb mixing effects in the ground and isobaric 0 + states of even-mass nuclei are investigated
Coulomb interaction in the supermultiplet basis
International Nuclear Information System (INIS)
Ruzha, Ya.Kh.; Guseva, T.V.; Tamberg, Yu.Ya.; Vanagas, V.V.
1989-01-01
An approximate expression for the matrix elements of the Coulomb interaction operator in the supermultiplet basis has been derived with the account for the orbitally-nonsymmetric terms. From the general expression a simplified formula for the Coulomb interaction energy has been proposed. On the basis of the expression obtained the contribution of the Coulomb interaction to the framework of a strongly restricted dynamic model in the light (4≤A≤40) and heavy (158≤A≤196) nuclei region has been studied. 19 refs.; 4 tabs
Modelling Coulomb Collisions in Anisotropic Plasmas
Hellinger, P.; Travnicek, P. M.
2009-12-01
Collisional transport in anisotropic plasmas is investigated comparing the theoretical transport coefficients (Hellinger and Travnicek, 2009) for anisotropic particles with the results of the corresponding Langevin equation, obtained as a generalization of Manheimer et al. (1997). References: Hellinger, P., and P. M. Travnicek (2009), On Coulomb collisions in bi-Maxwellian plasmas, Phys. Plasmas, 16, 054501. Manheimer, W. M., M. Lampe and G. Joyce (1997), Langevin representation of Coulomb collisions in PIC simulations, J. Comput. Phys., 138, 563-584.
Coulomb correction to elastic. alpha. -. alpha. scattering
Energy Technology Data Exchange (ETDEWEB)
Bera, P.K.; Jana, A.K.; Haque, N.; Talukdar, B. (Department of Physics, Visva-Bharati University, Santiniketan-731235, West Bengal, India (IN))
1991-02-01
The elastic {alpha}-{alpha} scattering is treated within the framework of a generalized phase-function method (GPFM). This generalization consists in absorbing the effect of Coulomb interaction in the comparison functions for developing the phase equation. Based on values of scattering phase shifts computed by the present method, it is concluded that the GPFM provides an uncomplicated approach to rigorous Coulomb correction in the {alpha}-{alpha} scattering.
Cavity QED experiments with ion Coulomb crystals
DEFF Research Database (Denmark)
Herskind, Peter Fønss; Dantan, Aurélien; Marler, Joan
2009-01-01
Cavity QED experimental results demonstrating collective strong coupling between ensembles of atomic ions cooled into Coulomb crystals and optical cavity fields have been achieved. Collective Zeeman coherence times of milliseconds have furthermore been obtained.......Cavity QED experimental results demonstrating collective strong coupling between ensembles of atomic ions cooled into Coulomb crystals and optical cavity fields have been achieved. Collective Zeeman coherence times of milliseconds have furthermore been obtained....
International Nuclear Information System (INIS)
Li Qun; Chen Yiheng
2008-01-01
The role played by the Coulombic traction for an interface crack in dissimilar piezoelectric materials is clarified. Based on the extended Stroh theory, the Coulombic traction, usually neglected in piezoelectric fracture, is imposed on the interface crack surfaces. It is found that the low-capacitance medium (air or vacuum) inside the crack gap yields some large Coulombic traction as compared to the applied mechanical loading whether the remanent polarization of piezoelectric material is considered or not. Thus, previous investigations based on the traction-free condition underestimate the role of the Coulombic traction and in turn may yield unexpected errors for the effective stress intensity factor (SIF) and energy release rate (ERR) at the crack tip. (technical note)
Conclusions. [hydrogen-based energy
1975-01-01
Conclusions are presented according to general areas of technology with some specific examples of research and technology needs identified. These conclusions provide a base for the future development of detailed program plans and identify research needs that are not being given attention or are not being supported at a sufficient level. Emphasis is placed on hydrogen production and use.
Interaction of charged 3D soliton with Coulomb center
International Nuclear Information System (INIS)
Rybakov, Yu.P.
1996-03-01
The Einstein - de Broglie particle-soliton concept is applied to simulate stationary states of an electron in a hydrogen atom. According to this concept, the electron is described by the localized regular solutions to some nonlinear equations. In the framework of Synge model for interacting scalar and electromagnetic fields a system of integral equations has been obtained, which describes the interaction between charged 3D soliton and Coulomb center. The asymptotic expressions for physical fields, describing soliton moving around the fixed Coulomb center, have been obtained with the help of integral equations. It is shown that the electron-soliton center travels along some stationary orbit around the Coulomb center. The electromagnetic radiation is absent as the Poynting vector has non-wave asymptote O(r -3 ) after averaging over angles, i.e. the existence of spherical surface corresponding to null Poynting vector stream, has been proved. Vector lines for Poynting vector are constructed in asymptotical area. (author). 22 refs, 2 figs
CONCLUSIONS Urban Children and Adolescents
Indian Academy of Sciences (India)
CONCLUSIONS Urban Children and Adolescents. Increasing prevalence of overweight and obesity and measures of regional (central) adiposity. High prevalence of markers of dysmetabolic state in urban adolescents. ~10% prevalence of dysglycemia in overweight / obese school children.
Martins, Cyril; Lenz, Benjamin; Perfetti, Luca; Brouet, Veronique; Bertran, François; Biermann, Silke
2018-03-01
We address the role of nonlocal Coulomb correlations and short-range magnetic fluctuations in the high-temperature phase of Sr2IrO4 within state-of-the-art spectroscopic and first-principles theoretical methods. Introducing an "oriented-cluster dynamical mean-field scheme", we compute momentum-resolved spectral functions, which we find to be in excellent agreement with angle-resolved photoemission spectra. We show that while short-range antiferromagnetic fluctuations are crucial to accounting for the electronic properties of Sr2IrO4 even in the high-temperature paramagnetic phase, long-range magnetic order is not a necessary ingredient of the insulating state. Upon doping, an exotic metallic state is generated, exhibiting cuprate-like pseudo-gap spectral properties, for which we propose a surprisingly simple theoretical mechanism.
CONCLUSIONS Urban Children and Adolescents
Indian Academy of Sciences (India)
First page Back Continue Last page Overview Graphics. CONCLUSIONS Urban Children and Adolescents. Increasing prevalence of overweight and obesity and measures of regional (central) adiposity. High prevalence of markers of dysmetabolic state in urban adolescents. ~10% prevalence of dysglycemia in overweight ...
CONCLUSIONS New Delhi Birth Cohort
Indian Academy of Sciences (India)
CONCLUSIONS New Delhi Birth Cohort. Crossing BMI centiles and early adiposity rebound associated with adult metabolic syndrome. BMI gain in infancy and early childhood – associated more with adult lean mass. BMI gain in later childhood / adolescence – associated more with adult fat mass and constituents of ...
Triaxiality near the 110Ru ground state from Coulomb excitation
Directory of Open Access Journals (Sweden)
D.T. Doherty
2017-03-01
Full Text Available A multi-step Coulomb excitation measurement with the GRETINA and CHICO2 detector arrays was carried out with a 430-MeV beam of the neutron-rich 110Ru (t1/2=12 s isotope produced at the CARIBU facility. This represents the first successful measurement following the post-acceleration of an unstable isotope of a refractory element. The reduced transition probabilities obtained for levels near the ground state provide strong evidence for a triaxial shape; a conclusion confirmed by comparisons with the results of beyond-mean-field and triaxial rotor model calculations.
Critical opalescence in the pure Coulomb system
International Nuclear Information System (INIS)
Bobrov, V.B.; Trigger, S.A.
2011-01-01
Highlights: → The review of the critical opalescence problem is presented. → Light scattering in a two-component electron-nuclear system is studied. → The exact relations between the structure factors and compressibility are found. → The obtained relations are valid for strong interaction for the Coulomb systems. → The experimental verification of these relations is possible for various elements. - Abstract: Based on the dielectric formalism and quantum field theory methods, the phenomenon of critical opalescence is explained for light scattering in pure matter as a two-component electron-nuclear system with Coulomb interaction. A similar phenomenon is shown to occur in the case of neutron scattering in pure substances as well. The obtained results are valid for quantum case and arbitrary strong Coulomb interaction. Thus, the relations between structure factors derived for the electron-nuclear system are the exact result of the quantum statistical mechanics.
Coulomb drag in the mesoscopic regime
DEFF Research Database (Denmark)
Mortensen, N. Asger; Flensberg, Karsten; Jauho, Antti-Pekka
2002-01-01
We present a theory for Coulomb drug between two mesoscopic systems which expresses the drag in terms of scattering matrices and wave functions. The formalism can be applied to both ballistic and disordered systems and the consequences can be studied either by numerical simulations or analytic...... means such as perturbation theory or random matrix theory. The physics of Coulomb drag in the mesoscopic regime is very different from Coulomb drag between extended electron systems. In the mesoscopic regime we in general find fluctuations of the drag comparable to the mean value. Examples are vanishing...... average drag for chaotic 2D-systems and dominating fluctuations of drag between quasi-ballistic wires with almost ideal transmission....
Coulomb drag in the mesoscopic regime
DEFF Research Database (Denmark)
Mortensen, N.A.; Flensberg, Karsten; Jauho, Antti-Pekka
2002-01-01
We present a theory for Coulomb drag between two mesoscopic systems which expresses the drag in terms of scattering matrices and wave functions. The formalism can be applied to both ballistic and disordered systems and the consequences can be studied either by numerical simulations or analytic...... means such as perturbation theory or random matrix theory. The physics of Coulomb drag in the mesoscopic regime is very different from Coulomb drag between extended electron systems. In the mesoscopic regime we in general find fluctuations of the drag comparable to the mean value. Examples are vanishing...... average drag for chaotic 2D-systems and dominating fluctuations of drag between quasi-ballistic wires with almost ideal transmission....
Chaotic motion at the nuclear Coulomb barrier; a quantal analysis
International Nuclear Information System (INIS)
Dasso, C.H.; Gallardo, M.; Saraceno, M.
1995-01-01
The coupling between relative motion and intrinsic surface vibrations in nuclear collisions introduces - at the classical level - a transition between ordered and disordered motion. Chaotic features set in near the Coulomb and centrifugal barriers in situations of weak absorption. We investigate here the solutions of the corresponding quantum scattering problem. The aim of this study is to identify possible manifestations of the underlying irregular structure in actual observables. To this end the correspondence between quantal wavefunctions and classical trajectories in phase space is explored. ((orig.))
Observation of a Coulomb flux tube
Greensite, Jeff; Chung, Kristian
2018-03-01
In Coulomb gauge there is a longitudinal color electric field associated with a static quark-antiquark pair. We have measured the spatial distribution of this field, and find that it falls off exponentially with transverse distance from a line joining the two quarks. In other words there is a Coulomb flux tube, with a width that is somewhat smaller than that of the minimal energy flux tube associated with the asymptotic string tension. A confinement criterion for gauge theories with matter fields is also proposed.
Coulomb dissociation of $^{20,21}$N
Röder, Marko; Adachi, Tatsuya; Aksyutina, Yulia; Alcantara, Juan; Altstadt, Sebastian; Alvarez-Pol, Hector; Ashwood, Nicholas; Atar, Leyla; Aumann, Thomas; Avdeichikov, Vladimir; Barr, M.; Beceiro, Saul; Bemmerer, Daniel; Benlliure, Jose; Bertulani, Carlos
2016-01-01
Neutron-rich light nuclei and their reactions play an important role for the creation of chemical elements. Here, data from a Coulomb dissociation experiment on $^{20,21}$N are reported. Relativistic $^{20,21}$N ions impinged on a lead target and the Coulomb dissociation cross section was determined in a kinematically complete experiment. Using the detailed balance theorem, the $^{19}\\mathrm{N}(\\mathrm{n},\\gamma)^{20}\\mathrm{N}$ and $^{20}\\mathrm{N}(\\mathrm{n},\\gamma)^{21}\\mathrm{N}$ excitati...
Coulomb dissociation of N 20,21
Röder, Marko; Adachi, Tatsuya; Aksyutina, Yulia; Alcantara, Juan; Altstadt, Sebastian; Alvarez-Pol, Hector; Ashwood, Nicholas; Atar, Leyla; Aumann, Thomas; Avdeichikov, Vladimir; Barr, M.; Beceiro, Saul; Bemmerer, Daniel; Benlliure, Jose; Bertulani, Carlos
2016-01-01
Neutron-rich light nuclei and their reactions play an important role in the creation of chemical elements. Here, data from a Coulomb dissociation experiment on N20,21 are reported. Relativistic N20,21 ions impinged on a lead target and the Coulomb dissociation cross section was determined in a kinematically complete experiment. Using the detailed balance theorem, the N19(n,γ)N20 and N20(n,γ)N21 excitation functions and thermonuclear reaction rates have been determined. The N19(n,γ)N20 rate is...
Coulomb drag in coherent mesoscopic systems
DEFF Research Database (Denmark)
Mortensen, Niels Asger; Flensberg, Karsten; Jauho, Antti-Pekka
2001-01-01
We present a theory for Coulomb drag between two mesoscopic systems. Our formalism expresses the drag in terms of scattering matrices and wave functions, and its range of validity covers both ballistic and disordered systems. The consequences can be worked out either by analytic means, such as th......We present a theory for Coulomb drag between two mesoscopic systems. Our formalism expresses the drag in terms of scattering matrices and wave functions, and its range of validity covers both ballistic and disordered systems. The consequences can be worked out either by analytic means...
Coulomb drag in coherent mesoscopic systems
DEFF Research Database (Denmark)
Mortensen, Asger; Flensberg, Karsten; Jauho, Antti-Pekka
2001-01-01
We present a theory for Coulomb drag between two mesoscopic systems. Our formalism expresses the drag in terms of scattering matrices and wave functions, and its range of validity covers both ballistic and disordered systems. The consequences can be worked out either by analytic means......, such as the random matrix theory, or by numerical simulations. We show that Coulomb drag is sensitive to localized states. which usual transport measurements do not probe. For chaotic 2D systems we find a vanishing average drag, with a nonzero variance. Disordered 1D wires show a finite drag, with a large variance...
Conclusions and a Research Agenda
DEFF Research Database (Denmark)
Richey, Lisa Ann; Ponte, Stefano
2012-01-01
a. Lisa Ann Richey, Roskilde University and Stefano Ponte, Danish Institute for International Studies - Brand Aid and Africa b. Fantu Cheru, Nordic Africa Institute - The Right to Consume: Compassion and the Intricate New Phase of Capitalism and Africa c. Rita Abrahamsen, University of Ottawa...... - Africa in a Global Political Economy of Symbolic Goods d. Graham Harrison, University of Sheffield - Images and Representations of Africa: Old, New and Beyond e. Claire Mercer, London School of Economics and Political Science - The Privatisation of Aid? f. Dan Brockington, University of Manchester...... - Celebrity Interventions g. Lisa Ann Richey, Roskilde University and Stefano Ponte, Danish Institute for International Studies – Conclusions and a Research Agenda...
On energy calculation for Coulomb systems
International Nuclear Information System (INIS)
Rebane, T.K.
1993-01-01
The problem of energy calculation for a Coulomb atomic-molecular system with arbitrary number N of particles is studied. The exponential wave functions explicitly depending on all N(N-1)/2 interparticle separations and taking into account the effects of correlation and nonadiabaticity are used. Straightforward use of these functions in many-particle systems with N > 3 is faced by time-consuming calculations of various multidimensional integrals with nonseparable variables. The number of these integrals increases as N 3 . This main obstacle can be obviated in the approach developed, based on the model Schroedinger equation combined with the virial and Hellmann-Feynman theorems. In this way the number of integrals in the expression for the matrix element of the many-particle Coulomb system Hamiltonian is significantly reduced: indeed, for a system with N = 4 particles only 7 instead of 43 integrals must be evaluated, for N = 5 only 10 instead of 101 integrals, etc. The number of different types of integral is also reduced. For a calculation of the energy of a 4-particle Coulomb system it is sufficient to calculate only 6 integrals of interparticle Coulomb interaction and the normalization integral. The results obtained offer a practical possibility for high-precision calculations of many-particle atomic-molecular systems with a detailed account of correlation and nonadiabaticity. 9 refs
Generalized Coulomb gauge without Gribov ambiguity
Energy Technology Data Exchange (ETDEWEB)
Fachin, S.; Parrinello, C. (New York Univ., NY (United States). Physics Dept.)
1992-05-01
We discuss a global gauge-fixing prescription that is free of the Gribov problem, preserves reflection positivity and contains as a limiting case the (maximal) Coulomb gauge. In such a formalism it is very easy to check that only color singlet states propagate in Euclidean time, for any value of [beta]. (orig.).
Coulomb suppression of the stellar enhancement factor
International Nuclear Information System (INIS)
Kiss, G.G.; Gyuerky, Gy.; Simon, A.; Fueloep, Zs.; Somorjai, E.
2008-01-01
Complete text of publication follows. Modern p process studies require large reaction networks, often including hundreds and thousands of nuclei and their respective reactions with light particles. Astrophysical reaction rates employed in reaction network calculations are determined either directly from cross sections or from the rate for the inverse reaction by applying detailed balance. The cross sections are known from experiment or predicted by theory. However, even when a reaction is experimentally accessible, often astrophysical rates cannot be directly measured. Excited states are thermally populated in an astrophysical plasma whereas only reactions on the ground state of the target can be investigated in the laboratory. A measure of the influence of the excited target states is given by the stellar enhancement factor f = r stellar /r g.s. , defined by the ratio of the stellar rate to the ground state rate. The enhancement factor f rev for the reverse reaction B(b,a)A (defined by having negative reaction Q value) is usually larger than the enhancement f forw of the forward reaction A(a,b)B (being the one with positive Q value) because more excited states are energetically accessible in nucleus B than in nucleus A. Therefore, it was assumed so far that more astrophysically relevant transitions are neglected when experimentally studying a reaction with negative Q value. However, there are cases for which f rev forw due to Coulomb suppression of a part of the energetically allowed transitions. This effect will be most pronounced in reactions with a charged particle in one and a neutral particle in the other channel, e.g. (n,p), but it can also appear when the entrance channel and exit channel have Coulomb barriers of different height, e.g. (p,α). Transitions from excited states to the same state in a compound nucleus are proceeding at smaller relative energy and are stronger suppressed by the Coulomb barrier. Thus, a prerequisite is that /Q/ is low compared to
Remote Spacecraft Attitude Control by Coulomb Charging
Stevenson, Daan
The possibility of inter-spacecraft collisions is a serious concern at Geosynchronous altitudes, where many high-value assets operate in proximity to countless debris objects whose orbits experience no natural means of decay. The ability to rendezvous with these derelict satellites would enable active debris removal by servicing or repositioning missions, but docking procedures are generally inhibited by the large rotational momenta of uncontrolled satellites. Therefore, a contactless means of reducing the rotation rate of objects in the space environment is desired. This dissertation investigates the viability of Coulomb charging to achieve such remote spacecraft attitude control. If a servicing craft imposes absolute electric potentials on a nearby nonspherical debris object, it will impart electrostatic torques that can be used to gradually arrest the object's rotation. In order to simulate the relative motion of charged spacecraft with complex geometries, accurate but rapid knowledge of the Coulomb interactions is required. To this end, a new electrostatic force model called the Multi-Sphere Method (MSM) is developed. All aspects of the Coulomb de-spin concept are extensively analyzed and simulated using a system with simplified geometries and one dimensional rotation. First, appropriate control algorithms are developed to ensure that the nonlinear Coulomb torques arrest the rotation with guaranteed stability. Moreover, the complex interaction of the spacecraft with the plasma environment and charge control beams is modeled to determine what hardware requirements are necessary to achieve the desired electric potential levels. Lastly, the attitude dynamics and feedback control development is validated experimentally using a scaled down terrestrial testbed. High voltage power supplies control the potential on two nearby conductors, a stationary sphere and a freely rotating cylinder. The nonlinear feedback control algorithms developed above are implemented to
Non-linear conductivity in Coulomb glasses
Energy Technology Data Exchange (ETDEWEB)
Voje, A.; Bergli, J. [Department of Physics, University of Oslo, P. O. Box 1048 Blindern, 0316 Oslo (Norway); Ortuno, M.; Somoza, A.M. [Departamento de Fisica - CIOyN, Universidad de Murcia, Murcia 30.071 (Spain); Caravaca, M.
2009-12-15
We have studied the nonlinear conductivity of two-dimensional Coulomb glasses. We have used a Monte Carlo algorithm to simulate the dynamic of the system under an applied electric field E. We have compared results for two different models: a regular square lattice with only diagonal disorder and a random array of sites with diagonal and off-diagonal disorder. We have found that for moderate fields the logarithm of the conductivity is proportional to {radical}(E)/T{sup 2}, reproducing experimental results. We have also found that in the nonlinear regime the site occupancy in the Coulomb gap follows a Fermi-Dirac distribution with an effective temperature T{sub eff} higher than the phonon bath temperature T. (Abstract Copyright [2009], Wiley Periodicals, Inc.)
Core polarization and Coulomb displacement energies
International Nuclear Information System (INIS)
Shlomo, S.; Love, W.G.
1982-01-01
The contributions of core polarization terms (other than the Auerbach-Kahana-Weneser (AKW) effect) to Coulomb displacement energies of mirror nuclei near A = 16 and A = 40 are examined within the particle-vibration coupling model. The parameters of the model are determined using updated data on the locations and strengths of multipole core excitations. In the absence of relevant data an energy-weighted sum rule (EWSR) is exploited. Taking into account multipole excitations up to L = 5 and subtracting the contributions which are due to short-range correlations, significant contributions (1-3%) to ΔEsub(c) are found. These corrections arise from particle coupling to low-lying collective states (long-range correlations). The implications of these results on the Coulomb energy problem are discussed. (Auth.)
Frictional Coulomb drag in strong magnetic fields
DEFF Research Database (Denmark)
Bønsager, Martin Christian; Flensberg, Karsten; Hu, Ben Yu-Kuang
1997-01-01
A treatment of frictional Coulomb drag between two two-dimensional electron layers in a strong perpendicular magnetic field, within the independent electron picture, is presented. Assuming fully resolved Landau levels, the linear response theory expression for the transresistivity rho(21) is eval......A treatment of frictional Coulomb drag between two two-dimensional electron layers in a strong perpendicular magnetic field, within the independent electron picture, is presented. Assuming fully resolved Landau levels, the linear response theory expression for the transresistivity rho(21......) is evaluated using diagrammatic techniques. The transresistivity is given by an integral over energy and momentum transfer weighted by the product of the screened interlayer interaction and the phase space for scattering events. We demonstrate, by a numerical analysis of the transresistivity, that for well...
Coulomb dissociation studies for astrophysical thermonuclear reactions
Energy Technology Data Exchange (ETDEWEB)
Motobayashi, T. [Dept. of Physics, Rikkyo Univ., Toshima, Tokyo (Japan)
1998-06-01
The Coulomb dissociation method was applied to several radiative capture processes of astrophysical interest. The method has an advantage of high experimental efficiency, which allow measurements with radioactive nuclear beams. The reactions {sup 13}N(p,{gamma}){sup 14}O and {sup 7}Be(p,{gamma}){sup 8}B are mainly discussed. They are the key reaction in the hot CNO cycle in massive stars and the one closely related to the solar neutrino problem, respectively. (orig.)
Coulomb explosion of large penetrating molecular clusters
International Nuclear Information System (INIS)
Wegner, H.E.; Thieberger, P.
1981-01-01
The main purpose of these Coulomb explosion measurements is to determine what kind of structure these and other complex molecules may have and also to determine what other special phenomena may come into play as these complex molecules pass through matter. Although the first preliminary measurements involving the Coulomb explosion of these molecules was reported at this workshop last year, the results are briefly summarized before going on to the more recent measurements obtained with a completely new kind of detector system. This new image intensifier detector system, coupled with a microcomputer, has proven to be a valuable tool in the study of the Coulomb explosion of complex molecules that penetrate matter. In the future, with some additional improvements in the system, and much better statistics for most of the molecules studied to date, it is expected that much new information will be gained about the structure of many kinds of complex molecular ions including the special effects that may be encountered when these fast molecular ions penetrate matter
Exciton condensation and perfect Coulomb drag.
Nandi, D; Finck, A D K; Eisenstein, J P; Pfeiffer, L N; West, K W
2012-08-23
Coulomb drag is a process whereby the repulsive interactions between electrons in spatially separated conductors enable a current flowing in one of the conductors to induce a voltage drop in the other. If the second conductor is part of a closed circuit, a net current will flow in that circuit. The drag current is typically much smaller than the drive current owing to the heavy screening of the Coulomb interaction. There are, however, rare situations in which strong electronic correlations exist between the two conductors. For example, double quantum well systems can support exciton condensates, which consist of electrons in one well tightly bound to holes in the other. 'Perfect' drag is therefore expected; a steady transport current of electrons driven through one quantum well should be accompanied by an equal current of holes in the other. Here we demonstrate this effect, taking care to ensure that the electron-hole pairs dominate the transport and that tunnelling of charge between the quantum wells, which can readily compromise drag measurements, is negligible. We note that, from an electrical engineering perspective, perfect Coulomb drag is analogous to an electrical transformer that functions at zero frequency.
Coulomb traction on a penny-shaped crack in a three dimensional piezoelectric body
Energy Technology Data Exchange (ETDEWEB)
Li, Qun; Kuna, Meinhard [TU Bergakademie Freiberg, Institute of Mechanics and Fluid Dynamics, Freiberg (Germany); Ricoeur, Andreas [University of Kassel, Institute of Mechanics, Kassel (Germany)
2011-06-15
The axisymmetric problem of a penny-shaped crack embedded in an infinite three-dimensional (3D) piezoelectric body is considered. A general formulation of Coulomb traction on the crack surfaces can be obtained based on thermodynamical considerations of electromechanical systems. Three-dimensional electroelastic solutions are derived by the classical complex potential theory when Coulomb traction is taken into account and the poling direction of piezoelectric body is perpendicular to the crack surfaces. Numerical results show that the magnitude of Coulomb tractions can be large, especially when a large electric field in connection with a small mechanical load is applied. Unlike the traditional traction-free crack model, Coulomb tractions induced by an applied electric field influence the Mode I stress intensity factor for a penny-shaped crack in 3D piezoelectric body. Moreover, compared to the current model, the traditional traction-free crack model always overestimates the effect of the applied electric load on the field intensity factors and energy release rates, which has consequences for 3D piezoelectric fracture mechanics. (orig.)
Influence of Coulomb screening on lateral lasing in VECSELs.
Wang, Chengao; Malloy, Kevin; Sheik-Bahae, Mansoor
2015-12-14
Parasitic lateral lasing in certain optically pumped semiconductor disc lasers drains the gain of the vertical mode and thus causes power scaling degradation and premature rollover in surface emitting operation. We have observed this effect in both multiple quantum wells (MQW) (GaInAs/GaAs) and double heterostructures (DHS) (GaInP/GaAs/GaInP) under pulsed excitation even when the gain chip lateral dimensions are much larger than the diameter of the pump laser. Lateral lasing occurs persistently between cleaved facets at a band-tail wavelength much longer than the peak of the gain. We show that the effect of bandgap renormalization due to Coulomb screening explains this phenomena. Exploiting the simple analytical plasma theory of bulk semiconductors (Banyai & Koch, 1986), we can account for such an effect in double heterostructures.
Coulomb excitation of {sup 8}Li
Energy Technology Data Exchange (ETDEWEB)
Assuncao, Marlete; Britos, Tatiane Nassar [Universidade Federal de Sao Paulo (UNIFESP), SP (Brazil). Dept. de Ciencias Exatas e da Terra; Descouvemont, Pierre [Universite Libre de Bruxelles (ULB), Brussels (Belgium). Physique Nucleaire Theorique et Physique Mathematique; Lepine-Szily, Alinka; Lichtenthaler Filho, Rubens; Barioni, Adriana; Silva, Diego Medeiros da; Pereira, Dirceu; Mendes Junior, Djalma Rosa; Pires, Kelly Cristina Cezaretto; Gasques, Leandro Romero; Morais, Maria Carmen; Added, Nemitala; Neto Faria, Pedro; Rec, Rafael [Universidade de Sao Paulo (IF/USP), SP (Brazil). Inst. de Fisica. Dept. de Fisica Nuclear
2012-07-01
Full text: This work shows the Coulomb Excitation of {sup 8}Li on targets that have effectively behavior of Rutherford in angles and energies of interest for determining the value of the B(E2) electromagnetic transition. Theoretical aspects involved in this type of measure, known as COULEX [1], and some results in the literature [2-3] will be presented. Some problems with the targets and measurement system while performing an experiment on Coulomb Excitation of {sup 8}Li will be discussed: the energy resolution, background, possible contributions of the primary beam and also the excited states of the target near the region of elastic and inelastic peaks. They will be illustrated by measurements of the Coulomb Excitation of {sup 8}Li on targets of {sup 197}Au and {sup 208}Pb using the system RIBRAS(Brazilian Radioactive Ion Beam). In this case, the {sup 8}Li beam(T{sub 1/2} = 838 ms)is produced by {sup 9}Be({sup 7}Li;{sup 8} Li){sup 8}Be reaction from RIBRAS system which is installed at Instituto de Fisica of the Universidade de Sao Paulo. The primary {sup 7L}i beam is provided by Pelletron Accelerator. [1] K. Alder and A. Winther, Electromagnetic Excitation, North-Holland, New York, 1975; [2] P. Descouvemont and D. Baye, Phys. Letts. B 292, 235-238, 1992; [3] J. A. Brown, F. D. Becchetti, J. W. Jaenecke, K, Ashktorab, and D. A. Roberts, J. J. Kolata, R. J. Smith, and K. Lamkin, R. E. Warner, Phys. Rev. Letts., 66, 19, 1991; [4] R. J. Smith, J. J Kolata, K. Lamkin and A. Morsard, F. D. Becchetti, J. A. Brown, W. Z. Liu, J. W. Jaenecke, and D. A. Roberts, R. E. Warner, Phys. Rev. C, 43, 5, 1991. (author)
Resonances in the two centers Coulomb system
Energy Technology Data Exchange (ETDEWEB)
Seri, Marcello
2012-09-14
In this work we investigate the existence of resonances for two-centers Coulomb systems with arbitrary charges in two and three dimensions, defining them in terms of generalized complex eigenvalues of a non-selfadjoint deformation of the two-center Schroedinger operator. After giving a description of the bifurcation of the classical system for positive energies, we construct the resolvent kernel of the operators and we prove that they can be extended analytically to the second Riemann sheet. The resonances are then defined and studied with numerical methods and perturbation theory.
Ordering transitions induced by Coulomb interactions
International Nuclear Information System (INIS)
Rovere, M.; Senatore, G.; Tosi, M.P.
1988-11-01
We briefly review recent progress in treating phase transitions to ordered states driven by Coulomb interactions. Wigner crystallization of the one-component plasma, in the degenerate Fermi limit and in the classical limit, is the foremost example and developments in its theory are discussed in some detail. Attention is also given to quasi-twodimensional realizations of the plasma model in the laboratory. The usefulness of these ideas in relation to freezing and ordering transitions is illustrated with reference to alkali metals, elemental and polar semiconductors, and various types of ionic systems (molten salts, colloidal suspensions and astrophysical plasmas). (author). 70 refs, 5 figs
QCD Coulomb Gauge Approach to Exotic Hadrons
Cotanch, Stephen R.; General, Ignacio J.; Wang, Ping
2006-01-01
The Coulomb gauge Hamiltonian model is used to calculate masses for selected J^{PC} states consisting of exotic combinations of quarks and gluons: ggg glueballs (oddballs), q bar{q} g hybrid mesons and q bar{q} q bar{q} tetraquark systems. An odderon Regge trajectory is computed for the J^{--} glueballs with intercept much smaller than the pomeron, explaining its nonobservation. The lowest 1^{-+} hybrid meson mass is found to be just above 2.2 GeV while the lightest tetraquark state mass with...
Hyperon excitation in nuclear coulomb field
International Nuclear Information System (INIS)
Vanyashin, A.V.; Nikitin, Yu.P.; Shan'gin, A.A.
1981-01-01
A possibility is studied to measure radiative decay partial widths from the 3/2 + decuplet hyperon resonances by means of the Coulomb excitation method of the octet hyperons. The expected contributions from the strong and electromagnetic interactions in the coherence range to the hyperon excitation cross sections on heavy nuclei and on the 4 He nucleus are estimated. The particle angular distributions in the reactions Σ-+A→Σ-(1385)+A and Λ+A→Σ 0 (1385)+A are analysed in order to determine the energy range where the background conditions are the most favorable to extract the electromagnetic mechanism of the hyperon excitation [ru
Bound and resonant states in Coulomb-like potentials
International Nuclear Information System (INIS)
Papp, Z.
1985-12-01
The potential separable expansion method was generalized for calculating bound and resonant states in Coulomb-like potentials. The complete set of Coulomb-Sturmian functions was taken as the basis to expand the short-range potential. On this basis the matrix elements of the Coulomb-Green functions were given in closed form as functions of the (complex) energy. The feasibility of the method is demonstrated by a numerical example. (author)
Coulomb implosion mechanism of negative ion acceleration in laser plasmas
Nakamura, T.; Fukuda, Y.; Yogo, A.; Tampo, M.; Kando, M.; Hayashi, Y.; Kameshima, T.; Pirozhkov, A. S.; Esirkepov, T. Zh.; Pikuz, T. A.; Faenov, A. Ya.; Daido, H.; Bulanov, S. V.
2008-01-01
Coulomb implosion mechanism of the negatively charged ion acceleration in laser plasmas is proposed. When a cluster target is irradiated by an intense laser pulse and the Coulomb explosion of positively charged ions occurs, the negative ions are accelerated inward. The maximum energy of negative ions is several times lower than that of positive ions. The theoretical description and Particle-in-Cell simulation of the Coulomb implosion mechanism and the evidence of the negative ion acceleration...
Color-singlet instantaneous potential in the coulomb gauge QCD
International Nuclear Information System (INIS)
Nakagawa, Yoshiyuki; Toki, Hiroshi; Nakamura, Atsushi; Saito, Takuya
2007-01-01
We study the Coulomb gauge confinement mechanism in the quenched lattice QCD simulations. It is found that the color-Coulomb instantaneous potential in the color-singlet channel between two quarks grows linearly at large distances; namely, the color-Coulomb interaction is a source of color confinement. However, the linearity of this potential remains even in the quark-gluon plasma phase. We discuss the relation between this thermal Coulomb-string tension and a magnetic scaling introduced as an infrared cutoff of the thermal QCD theory. (author)
Heat Coulomb blockade of one ballistic channel
Sivre, E.; Anthore, A.; Parmentier, F. D.; Cavanna, A.; Gennser, U.; Ouerghi, A.; Jin, Y.; Pierre, F.
2018-02-01
Quantum mechanics and Coulomb interaction dictate the behaviour of small circuits. The thermal implications cover fundamental topics from quantum control of heat to quantum thermodynamics, with prospects of novel thermal machines and an ineluctably growing influence on nanocircuit engineering. Experimentally, the rare observations thus far include the universal thermal conductance quantum and heat interferometry. However, evidence for many-body thermal effects paving the way to markedly different heat and electrical behaviours in quantum circuits remains wanting. Here we report on the observation of the Coulomb blockade of electronic heat flow from a small metallic circuit node, beyond the widespread Wiedemann-Franz law paradigm. We demonstrate this thermal many-body phenomenon for perfect (ballistic) conduction channels to the node, where it amounts to the universal suppression of precisely one quantum of conductance for the transport of heat, but none for electricity. The inter-channel correlations that give rise to such selective heat current reduction emerge from local charge conservation, in the floating node over the full thermal frequency range (<~temperature × kB/h). This observation establishes the different nature of the quantum laws for thermal transport in nanocircuits.
Transport Through a Coulomb Blockaded Majorana Nanowire
Zazunov, Alex; Egger, Reinhold; Yeyati, Alfredo Levy; Hützen, Roland; Braunecker, Bernd
In one-dimensional (1D) quantum wires with strong spin-orbit coupling and a Zeeman field, a superconducting substrate can induce zero-energy Majorana bound states located near the ends of the wire. We study electronic properties when such a wire is contacted by normal metallic or superconducting electrodes. A special attention is devoted to Coulomb blockade effects. We analyze the "Majorana single-charge transistor" (MSCT), i.e., a floating Majorana wire contacted by normal metallic source and drain contacts, where charging effects are important. We describe Coulomb oscillations in this system and predict that Majorana fermions could be unambiguously detected by the emergence of sideband peaks in the nonlinear differential conductance. We also study a superconducting variant of the MSCT setup with s-wave superconducting (instead of normal-conducting) leads. In the noninteracting case, we derive the exact current-phase relation (CPR) and find π-periodic behavior with negative critical current for weak tunnel couplings. Charging effects then cause the anomalous CPR I(\\varphi ) = Ic\\cos \\varphi, where the parity-sensitive critical current I c provides a signature for Majorana states.
Coulomb explosion imaging of H+3
International Nuclear Information System (INIS)
Kreckel, H.
2000-01-01
The present work deals with the determination of the spatial structure of the H 3 + molecular ion. The structure of this molecule was investigated at the TSR storage ring of the Max Planck Institut fuer Kernphysik using the Coulomb Explosion Imaging (CEI) technique, which provides a relatively direct approach to the measurement of molecular configurations. The method of foil induced Coulomb Explosion Imaging and the experimental setup at the TSR are described. The classification of the vibrational levels of the H 3 + ion is described and the underlying group theoretical methods are developed. The results of the measurement are analyzed with regard to anisotropies and possible influences of the target foil and the detector are discussed. Then the subset of the data where these influences are small is selected and is compared to two different theoretical calculations. Finally the vibrational relaxation of the H 3 + ion in the storage ring is analysed and the lifetime of the metastable breathing mode A 1 (1, 0 0 ) is determined. (orig.) [de
ATOMIC SCREENING AND INTERSITE COULOMB REPULSION IN STRONGLY CORRELATED SYSTEMS
Meinders, M.B J; van den Brink, J.; Lorenzana, J.; Sawatzky, G.A
1995-01-01
We consider the influence of a nearest-neighbor Coulomb interaction in an extended Hubbard model and introduce an interaction term which simulates atomic polarizabilities. The inclusion of atomic polarizabilities in the model has the effect of screening the on-site Coulomb interaction for charged
Antilocalization of Coulomb Blockade in a Ge-Si Nanowire
DEFF Research Database (Denmark)
Higginbotham, Andrew P.; Kuemmeth, Ferdinand; Larsen, Thorvald Wadum
2014-01-01
The distribution of Coulomb blockade peak heights as a function of magnetic field is investigated experimentally in a Ge-Si nanowire quantum dot. Strong spin-orbit coupling in this hole-gas system leads to antilocalization of Coulomb blockade peaks, consistent with theory. In particular, the peak...
4-center STO interelectron repulsion integrals with Coulomb Sturmians
DEFF Research Database (Denmark)
Avery, James Emil; Avery, John Scales
2018-01-01
Abstract We present a method for evaluating 4-center electron repulsion integrals (ERI) for Slater-type orbitals by way of expansions in terms of Coulomb Sturmians. The ERIs can then be evaluated using our previously published methods for rapid evaluation of Coulomb Sturmians through hyperspherical...
Plasmons in Dimensionally Mismatched Coulomb Coupled Graphene Systems
DEFF Research Database (Denmark)
Badalyan, S. M.; Shylau, A. A.; Jauho, Antti-Pekka
2017-01-01
We calculate the plasmon dispersion relation for Coulomb coupled metallic armchair graphene nanoribbons and doped monolayer graphene. The crossing of the plasmon curves, which occurs for uncoupled 1D and 2D systems, is split by the interlayer Coulomb coupling into a lower and an upper plasmon...
Correlated Coulomb drag in capacitively coupled quantum-dot structures
DEFF Research Database (Denmark)
Kaasbjerg, Kristen; Jauho, Antti-Pekka
2016-01-01
We study theoretically Coulomb drag in capacitively coupled quantum dots (CQDs) -- a biasdriven dot coupled to an unbiased dot where transport is due to Coulomb mediated energy transfer drag. To this end, we introduce a master-equation approach which accounts for higher-order tunneling (cotunneling...
Effective Coulomb interaction in multiorbital system
International Nuclear Information System (INIS)
Hase, Izumi; Yanagisawa, Takashi
2013-01-01
Transition metal atom generally takes various valences, and sometimes there are some 'missing valences', for example Fe usually takes 2+, 3+ and 5+, but does not take other valences so often. We have calculated the atomic multiplet energies for the high-spin and lowspin configurations within the ligand-field theory and the Hartree-Fock approximation, and found that the Coulomb interaction energy (U eff ) becomes small when the valence is 'missing'. In case U eff B /Fe only when U eff increased in most cases, but in some special cases U eff decreases and falls below the value U − 3J, which is the least value of the undistorted system.
Effective temperature in relaxation of Coulomb glasses.
Somoza, A M; Ortuño, M; Caravaca, M; Pollak, M
2008-08-01
We study relaxation in two-dimensional Coulomb glasses up to macroscopic times. We use a kinetic Monte Carlo algorithm especially designed to escape efficiently from deep valleys around metastable states. We find that, during the relaxation process, the site occupancy follows a Fermi-Dirac distribution with an effective temperature much higher than the real temperature T. Long electron-hole excitations are characterized by T(eff), while short ones are thermalized at T. We argue that the density of states at the Fermi level is proportional to T(eff) and is a good thermometer to measure it. T(eff) decreases extremely slowly, roughly as the inverse of the logarithm of time, and it should affect hopping conductance in many experimental circumstances.
Powerful Coulomb-drag thermoelectric engine
Daré, A.-M.; Lombardo, P.
2017-09-01
We investigate a thermoelectric nanoengine whose properties are steered by Coulomb interaction. The device whose design decouples charge and energy currents is made up of two interacting quantum dots connected to three different reservoirs. We show that, by tailoring the tunnel couplings, this setup can be made very attractive for energy-harvesting prospects, due to a delivered power that can be of the order of the quantum bound [R. S. Whitney, Phys. Rev. Lett. 112, 130601 (2014), 10.1103/PhysRevLett.112.130601; Entropy 18, 208 (2016), 10.3390/e18060208], with a concomitant fair efficiency. To unveil its properties beyond the sequential quantum master equation, we apply a nonequilibrium noncrossing approximation in the Keldysh Green's function formalism, and a quantum master equation that includes cotunneling processes. Both approaches are rather qualitatively similar in a large operating regime where sequential tunneling alone fails.
Coulomb excitation of {sup 107}Sn
Energy Technology Data Exchange (ETDEWEB)
DiJulio, D.D.; Cederkall, J.; Fahlander, C. [Lund University, Physics Department, 118, Lund (Sweden); Ekstroem, A. [University of Oslo, Department of Physics and Center of Mathematics for Applications, Oslo (Norway); Hjorth-Jensen, M. [University of Oslo, Department of Physics and Center of Mathematics for Applications, Oslo (Norway); Michigan State University, National Superconducting Cyclotron Laboratory and Department of Physics and Astronomy, East Lansing, MI (United States); Albers, M.; Blazhev, A.; Fransen, C.; Geibel, K.; Hess, H.; Reiter, P.; Seidlitz, M.; Taprogge, J.; Warr, N. [University of Cologne, Institute of Nuclear Physics, Cologne (Germany); Bildstein, V.; Gernhaeuser, R.; Wimmer, K. [Technische Universitaet Muenchen, Physik Department E12, Garching (Germany); Darby, I.; Witte, H. de [Instituut voor Kern- en Stralingsfysica, Leuven (Belgium); Davinson, T. [University of Edinburgh, Department of Physics and Astronomy, Edinburgh (United Kingdom); Diriken, J. [Instituut voor Kern- en Stralingsfysica, Leuven (Belgium); Studiecentrum voor Kernenergie/Centre d' Etude de l' energie Nucleaire (SCK CEN), Mol (Belgium); Goergen, A.; Siem, S.; Tveten, G.M. [University of Oslo, Department of Physics, Oslo (Norway); Iwanicki, J. [University of Warsaw, Heavy Ion Laboratory, Warsaw (Poland); Lutter, R. [Ludwig-Maximilians-Universitaet Muenchen, Fakultaet fuer Physik, Garching (Germany); Scheck, M. [University of Liverpool, Oliver Lodge Laboratory, Liverpool (United Kingdom); Walle, J.V. de [PH Department, Geneva 23 (Switzerland); Voulot, D.; Wenander, F. [AB Department, Geneva 23 (Switzerland)
2012-07-15
The radioactive isotope {sup 107}Sn was studied using Coulomb excitation at the REX-ISOLDE facility at CERN. This is the lightest odd-Sn nucleus examined using this technique. The reduced transition probability of the lowest-lying 3/2{sup +} state was measured and is compared to shell-model predictions based on several sets of single-neutron energies relative to {sup 100}Sn. Similar to the transition probabilities for the 2{sup +} states in the neutron-deficient even-even Sn nuclei, the measured value is underestimated by shell-model calculations. Part of the strength may be recovered by considering the ordering of the d{sub 5/2} and g{sub 7/2} single-neutron states. (orig.)
The Coulomb potential in quantum mechanics and related topics
International Nuclear Information System (INIS)
Haeringen, H. van.
1978-01-01
This dissertation consists of an analytic study of the Coulomb interaction in nonrelativistic quantum mechanics and some related topics. The author investigates in a number of self-contained articles various interesting and important properties of the Coulomb potential. Some of these properties are shared by other potentials which also play a role in quantum mechanics. For such related interactions a comparative study is made. The principal difficulties in the description of proton-deuteron scattering and break-up reactions, due to the Coulomb interaction, are studied by working out a simple model. The bound states are studied for the Coulomb plus Yamaguchi potential, for the symmetric shifted Coulomb potential, and for local potentials with an inverse-distance-squared asymptotic behaviour. (Auth.)
Calculations for the one-dimensional soft Coulomb problem and the hard Coulomb limit.
Gebremedhin, Daniel H; Weatherford, Charles A
2014-05-01
An efficient way of evolving a solution to an ordinary differential equation is presented. A finite element method is used where we expand in a convenient local basis set of functions that enforce both function and first derivative continuity across the boundaries of each element. We also implement an adaptive step-size choice for each element that is based on a Taylor series expansion. This algorithm is used to solve for the eigenpairs corresponding to the one-dimensional soft Coulomb potential, 1/sqrt[x(2)+β(2)], which becomes numerically intractable (because of extreme stiffness) as the softening parameter (β) approaches zero. We are able to maintain near machine accuracy for β as low as β = 10(-8) using 16-digit precision calculations. Our numerical results provide insight into the controversial one-dimensional hydrogen atom, which is a limiting case of the soft Coulomb problem as β → 0.
1976-01-01
The study concerning the contact between a tyre and the road surface was conducted in three phases. In the first phase the first and second-order factors were separated. The factors: type of road surface, tyre type, tread depth, water depth, tyre pressure and tyre load were included in an
The statistical mechanics of the classical two-dimensional Coulomb gas is exactly solved
International Nuclear Information System (INIS)
Samaj, L
2003-01-01
The model under consideration is a classical 2D Coulomb gas of pointlike positive and negative unit charges, interacting via a logarithmic potential. In the whole stability range of temperatures, the equilibrium statistical mechanics of this fluid model is exactly solvable via an equivalence with the integrable 2D sine-Gordon field theory. The exact solution includes the bulk thermodynamics, special cases of the surface thermodynamics and the large-distance asymptotic behaviour of the two-body correlation functions
Subdifferential-based implicit return-mapping operators in Mohr-Coulomb plasticity
Czech Academy of Sciences Publication Activity Database
Sysala, Stanislav; Čermák, M.; Ligurský, Tomáš
2017-01-01
Roč. 97, č. 12 (2017), s. 1502-1523 ISSN 0044-2267 R&D Projects: GA MŠk LQ1602 Institutional support: RVO:68145535 Keywords : consistent tangent operator * implicit return-mapping scheme * incremental limit analysis * infinitesimal plasticity * Mohr-Coulomb yield surface Subject RIV: BA - General Mathematics OBOR OECD: Applied mathematics Impact factor: 1.332, year: 2016 http://onlinelibrary.wiley.com/doi/10.1002/zamm.201600215/full
Subdifferential-based implicit return-mapping operators in Mohr-Coulomb plasticity
Czech Academy of Sciences Publication Activity Database
Sysala, Stanislav; Čermák, M.; Ligurský, Tomáš
2017-01-01
Roč. 97, č. 12 (2017), s. 1502-1523 ISSN 0044-2267 R&D Projects: GA MŠk LQ1602 Institutional support: RVO:68145535 Keywords : consistent tangent operator * implicit return-mapping scheme * incremental limit analysis * infinitesimal plasticity * Mohr-Coulomb yield surface Subject RIV: BA - General Mathematics Impact factor: 1.332, year: 2016 http://onlinelibrary.wiley.com/doi/10.1002/zamm.201600215/full
Hiratsuka, Y.; Oryu, S.; Gojuki, S.
2011-05-01
Reliability of the screened Coulomb renormalization method, which was proposed in an elegant way by Alt-Sandhas-Zankel-Ziegelmann (ASZZ), is discussed on the basis of "two-potential theory" for the three-body AGS equations with the Coulomb potential. In order to obtain ASZZ's formula, we define the on-shell Møller function, and calculate it by using the Haeringen criterion, i.e. "the half-shell Coulomb amplitude is zero". By these two steps, we can finally obtain the ASZZ formula for a small Coulomb phase shift. Furthermore, the reliability of the Haeringen criterion is thoroughly checked by a numerically rigorous calculation for the Coulomb LS-type equation. We find that the Haeringen criterion can be satisfied only in the higher energy region. We conclude that the ASZZ method can be verified in the case that the on-shell approximation to the Møller function is reasonable, and the Haeringen criterion is reliable.
International Nuclear Information System (INIS)
Hiratsuka, Y.; Oryu, S.; Gojuki, S.
2011-01-01
Reliability of the screened Coulomb renormalization method, which was proposed in an elegant way by Alt-Sandhas-Zankel-Ziegelmann (ASZZ), is discussed on the basis of 'two-potential theory' for the three-body AGS equations with the Coulomb potential. In order to obtain ASZZ's formula, we define the on-shell Moller function, and calculate it by using the Haeringen criterion, i. e. 'the half-shell Coulomb amplitude is zero'. By these two steps, we can finally obtain the ASZZ formula for a small Coulomb phase shift. Furthermore, the reliability of the Haeringen criterion is thoroughly checked by a numerically rigorous calculation for the Coulomb LS-type equation. We find that the Haeringen criterion can be satisfied only in the higher energy region. We conclude that the ASZZ method can be verified in the case that the on-shell approximation to the Moller function is reasonable, and the Haeringen criterion is reliable. (author)
Some studies in scatering by Coulomb modified nuclear potentials
International Nuclear Information System (INIS)
Laha, U.
1988-01-01
Recently, there has been a surge of interest in theoretical questions concerning the Coulomb nuclear problems with the main emphasis on their off-shell behaviour. Earlier approaches to the problem made use of a version of the two-potential formula as used by Bajzer. A slightly different point of view is presented here. An expression for the interacting Green's function for motion in the Coulomb plus Graz potential is constructed and used to obtain the half-off-shell T matrix in the ''maximal reduced form''. Similar results were also derived for the off-shell Jost functions. It is explicitly demonstrated that Coulomb and Coulomb-like potentials the half-off-shell T matrix can be expressed in terms of on-and off-shell Jost functions in the same way as one does for a purely short range interaction. In presenting the results for T matrix and other related quantities, the Coulomb effect is included rigorously. Results clearly delineate the branch point singularities originating from the long range nature of the Coulomb interaction and thus provide a better understanding of the off-shell two-body Coulomb-like T matrices. It is hoped that these results will form an adequate starting point for rigorous calculations on few-body systems with charges. (author). 16 refs
Do nuclei go pear-shaped? Coulomb excitation of 220Rn and 224Ra at REX-ISOLDE (CERN
Directory of Open Access Journals (Sweden)
Scheck M.
2015-01-01
Full Text Available The IS475 collaboration conducted Coulomb-excitation experiments with post-accelerated radioactive 220Rn and 224Ra beams at the REX-ISOLDE facility. The beam particles (Ebeam: 2.83 MeV/u were Coulomb excited using 60Ni, 114Cd, and 120Sn scattering targets. De-excitation γ-rays were detected employing the Miniball array and scattered particles were detected in a silicon detector. Exploiting the Coulomb-excitation code GOSIA for each nucleus several matrix elements could be obtained from the measured γ-ray yields. The extracted ‹3−||E3||0+› matrix element allows for the conclusion that, while 220Rn represents an octupole vibrational system, 224Ra has already substantial octupole correlations in its ground state. This finding has implications for the search of CP-violating Schiff moments in the atomic systems of the adjacent odd-mass nuclei.
Theory and simulation of strong correlations in quantum Coulomb systems
Bonitz, M.; Semkat, D.; Filinov, A.; Golubnychyi, V.; Kremp, D.; Gericke, D. O.; Murillo, M. S.; Filinov, V.; Fortov, V.; Hoyer, W.; Koch, S. W.
2003-06-01
Strong correlations in quantum Coulomb systems (QCS) are attracting increasing interest in many fields ranging from dense plasmas and semiconductors to metal clusters and ultracold trapped ions. Examples are bound states in dense plasmas (atoms, molecules, clusters) and semiconductors (excitons, trions, biexcitons) or Coulomb crystals. We present first-principle simulation results of these systems including path integral Monte Carlo simulations of the equilibrium behaviour of dense hydrogen and electron-hole plasmas and molecular dynamics and quantum kinetic theory simulations of the nonequilibrium properties of QCS. Finally, we critically assess potential and limitations of the various methods in their application to Coulomb systems.
Coulomb displacement energies in nuclei: a new approach
International Nuclear Information System (INIS)
Auerbach, N.; Tel Aviv Univ.; Bernard, V.; Nguyen, V.G.
1978-04-01
The neutron core polarization gives rise to an important correction to the direct Coulomb contribution when one calculates the Coulomb displacement energies. In the Hartree-Fock model it is shown that this correction is about 2% to 4.5% in medium and heavy nuclei. The core polarization as well as other higher order effects can be included by using a selfconsistent description of the analog state in a complete proton particle-neutron hole space. The Coulomb displacement energies in 48 Ca, 88 Sr and 208 Pb have been calculated using Skyrme interactions SIII and SIV. A good agreement with experiment is obtained
Coulomb implosion mechanism of negative ion acceleration in laser plasmas
Energy Technology Data Exchange (ETDEWEB)
Nakamura, T., E-mail: nakamura.tatsufumi@jaea.go.j [Kansai Photon Science Institute (JAEA), 8-1 Umemidai, Kizugawa, Kyoto 619-0215 (Japan); Fukuda, Y.; Yogo, A.; Tampo, M.; Kando, M.; Hayashi, Y.; Kameshima, T.; Pirozhkov, A.S.; Esirkepov, T.Zh.; Pikuz, T.A.; Faenov, A.Ya.; Daido, H.; Bulanov, S.V. [Kansai Photon Science Institute (JAEA), 8-1 Umemidai, Kizugawa, Kyoto 619-0215 (Japan)
2009-07-06
Coulomb implosion mechanism of the negatively charged ion acceleration in laser plasmas is proposed. When a cluster target is irradiated by an intense laser pulse and the Coulomb explosion of positively charged ions occurs, the negative ions are accelerated inward. The maximum energy of negative ions is several times lower than that of positive ions. We present the theoretical description and Particle-in-Cell simulation results of the Coulomb implosion mechanism, and show the evidence of the negative ion acceleration in the experiments on the high intensity laser pulse interaction with the cluster targets.
Association between competing interests and authors' conclusions
DEFF Research Database (Denmark)
Kjaergard, Lise L; Als-Nielsen, Bodil
2002-01-01
To assess the association between competing interests and authors' conclusions in randomised clinical trials.......To assess the association between competing interests and authors' conclusions in randomised clinical trials....
Nemutudi, R.; Kataoka, M.; Ford, C. J. B.; Appleyard, N. J.; Pepper, M.; Ritchie, D. A.; Jones, G. A. C.
2004-03-01
Atomic force microscope (AFM) lithography is used to fabricate a charge detector. Experimental results are presented showing the lateral detection of Coulomb blockade events using a narrow constriction located in close proximity to a quantum dot. Both the dot and the constriction are patterned by writing oxide lines on a semiconductor surface with a conducting tip of an AFM. On a shallow two-dimensional electron gas (2DEG), the written oxide lifts the bottom of the conduction band above the Fermi level, leaving the 2DEG depleted beneath it. With its inherent ability to draw fine lines, the AFM presents a suitable fabrication technique for noninvasive experiments in which a phenomenon, such as Coulomb blockade, can be detected without necessarily injecting current across the dot.
Correlation functions of Coulomb branch operators
Energy Technology Data Exchange (ETDEWEB)
Gerchkovitz, Efrat [Weizmann Institute of Science,Rehovot 76100 (Israel); Gomis, Jaume [Perimeter Institute for Theoretical Physics,Waterloo, ON N2L 2Y5 (Canada); Ishtiaque, Nafiz [Perimeter Institute for Theoretical Physics,Waterloo, ON N2L 2Y5 (Canada); Department of Physics, University of Waterloo,Waterloo, ON N2L 3G1 (Canada); Karasik, Avner; Komargodski, Zohar [Weizmann Institute of Science,Rehovot 76100 (Israel); Pufu, Silviu S. [Joseph Henry Laboratories, Princeton University,Princeton, NJ 08544 (United States)
2017-01-24
We consider the correlation functions of Coulomb branch operators in four-dimensional N=2 Superconformal Field Theories (SCFTs) involving exactly one anti-chiral operator. These extremal correlators are the “minimal' non-holomorphic local observables in the theory. We show that they can be expressed in terms of certain determinants of derivatives of the four-sphere partition function of an appropriate deformation of the SCFT. This relation between the extremal correlators and the deformed four-sphere partition function is non-trivial due to the presence of conformal anomalies, which lead to operator mixing on the sphere. Evaluating the deformed four-sphere partition function using supersymmetric localization, we compute the extremal correlators explicitly in many interesting examples. Additionally, the representation of the extremal correlators mentioned above leads to a system of integrable differential equations. We compare our exact results with previous perturbative computations and with the four-dimensional tt{sup ∗} equations. We also use our results to study some of the asymptotic properties of the perturbative series expansions we obtain in N=2 SQCD.
Deep inelastic scattering near the Coulomb barrier
Energy Technology Data Exchange (ETDEWEB)
Gehring, J.; Back, B.; Chan, K. [and others
1995-08-01
Deep inelastic scattering was recently observed in heavy ion reactions at incident energies near and below the Coulomb barrier. Traditional models of this process are based on frictional forces and are designed to predict the features of deep inelastic processes at energies above the barrier. They cannot be applied at energies below the barrier where the nuclear overlap is small and friction is negligible. The presence of deep inelastic scattering at these energies requires a different explanation. The first observation of deep inelastic scattering near the barrier was in the systems {sup 124,112}Sn + {sup 58,64}Ni by Wolfs et al. We previously extended these measurements to the system {sup 136}Xe + {sup 64}Ni and currently measured the system {sup 124}Xe + {sup 58}Ni. We obtained better statistics, better mass and energy resolution, and more complete angular coverage in the Xe + Ni measurements. The cross sections and angular distributions are similar in all of the Sn + Ni and Xe + Ni systems. The data are currently being analyzed and compared with new theoretical calculations. They will be part of the thesis of J. Gehring.
Coulomb excitation of {sup 48}K
Energy Technology Data Exchange (ETDEWEB)
Siebeck, Burkhard; Blazhev, Andrey; Geibel, Kerstin; Hess, Herbert; Reiter, Peter; Seidlitz, Michael; Schneiders, David; Steinbach, Tim; Warr, Nigel [IKP, Universitaet zu Koeln (Germany); Bauer, Christopher [IKP, TU Darmstadt (Germany); Witte, Hilde de [KU Leuven (Belgium); Klintefjord, Malin [University of Oslo (Norway); Pakarinen, Janne [University of Jyvaeskylae (Finland); Rapisarda, Elisa [KU Leuven (Belgium); CERN, Genf (Switzerland); Scheck, Marcus [University of the West of Scotland, Paisley (United Kingdom); Voulot, Didier; Wenander, Frederik [CERN, Genf (Switzerland)
2016-07-01
Potassium isotopes in the direct vicinity of doubly-magic nuclei are of great interest and subject of recent shell model calculations. These show that the ground states of most K isotopes are dominated by a π0p0h configuration, while {sup 47}K and {sup 49}K have a major π2p2h contribution. However, the situation is not clear for the odd-odd isotope {sup 48}K, which shows a mixture between 0p0h and 2p2h. In order to study the coupling between the νp{sub 3/2}-shell and the πs{sub 1/2}-, πd{sub 3/2}-shells, transition matrix elements are deduced from a Coulomb excitation experiment performed with MINIBALL at REX-ISOLDE. A {sup 104}Pd target was irradiated by a radioactive {sup 48}K beam. γ rays of both target and projectile deexcitation have been observed. Those yields, together with available spectroscopic data, allow the detemination of transition matrix elements with GOSIA2. The new findings are compared to shell model calculations.
Shakeoff Ionization near the Coulomb Barrier Energy
Sharma, Prashant; Nandi, T.
2017-11-01
We measure the projectile K x-ray spectra as a function of the beam energies around the Coulomb barrier in different collision systems. The energy is scanned in small steps around the barrier aiming to explore the nuclear effects on the elastically scattered projectile ions. The variation of the projectile x-ray energy with the ion-beam energies exhibits an unusual increase in between the interaction barrier and fusion barrier energies. This additional contribution to the projectile ionization can be attributed to the shakeoff of outer-shell electrons of the projectile ions due to the sudden nuclear recoil (˜10-21 sec ) caused by the attractive nuclear potential, which gets switched on near the interaction barrier energy. In the sudden approximation limit, the theoretical shakeoff probability calculation due to the nuclear recoil explains the observed data well. In addition to its fundamental interest, such processes can play a significant role in dark matter detection through the possible mechanism of x-ray emissions, where the weakly interacting massive particle-nucleus elastic scattering can lead to the nuclear-recoil-induced inner-shell vacancy creations. Furthermore, the present work may provide new prospects for atomic physics research at barrier energies as well as provide a novel technique to perform barrier distribution studies for two-body systems.
Multilevel Monte Carlo simulation of Coulomb collisions
Energy Technology Data Exchange (ETDEWEB)
Rosin, M.S., E-mail: msr35@math.ucla.edu [Mathematics Department, University of California at Los Angeles, Los Angeles, CA 90036 (United States); Department of Mathematics and Science, Pratt Institute, Brooklyn, NY 11205 (United States); Ricketson, L.F. [Mathematics Department, University of California at Los Angeles, Los Angeles, CA 90036 (United States); Dimits, A.M. [Lawrence Livermore National Laboratory, L-637, P.O. Box 808, Livermore, CA 94511-0808 (United States); Caflisch, R.E. [Mathematics Department, University of California at Los Angeles, Los Angeles, CA 90036 (United States); Institute for Pure and Applied Mathematics, University of California at Los Angeles, Los Angeles, CA 90095 (United States); Cohen, B.I. [Lawrence Livermore National Laboratory, L-637, P.O. Box 808, Livermore, CA 94511-0808 (United States)
2014-10-01
We present a new, for plasma physics, highly efficient multilevel Monte Carlo numerical method for simulating Coulomb collisions. The method separates and optimally minimizes the finite-timestep and finite-sampling errors inherent in the Langevin representation of the Landau–Fokker–Planck equation. It does so by combining multiple solutions to the underlying equations with varying numbers of timesteps. For a desired level of accuracy ε, the computational cost of the method is O(ε{sup −2}) or O(ε{sup −2}(lnε){sup 2}), depending on the underlying discretization, Milstein or Euler–Maruyama respectively. This is to be contrasted with a cost of O(ε{sup −3}) for direct simulation Monte Carlo or binary collision methods. We successfully demonstrate the method with a classic beam diffusion test case in 2D, making use of the Lévy area approximation for the correlated Milstein cross terms, and generating a computational saving of a factor of 100 for ε=10{sup −5}. We discuss the importance of the method for problems in which collisions constitute the computational rate limiting step, and its limitations.
Coulomb-interacting billiards in circular cavities
International Nuclear Information System (INIS)
Solanpää, J; Räsänen, E; Nokelainen, J; Luukko, P J J
2013-01-01
We apply a molecular dynamics scheme to analyze classically chaotic properties of a two-dimensional circular billiard system containing two Coulomb-interacting electrons. As such, the system resembles a prototype model for a semiconductor quantum dot. The interaction strength is varied from the noninteracting limit with zero potential energy up to the strongly interacting regime where the relative kinetic energy approaches zero. At weak interactions the bouncing maps show jumps between quasi-regular orbits. In the strong-interaction limit we find an analytic expression for the bouncing map. Its validity in the general case is assessed by comparison with our numerical data. To obtain a more quantitative view on the dynamics as the interaction strength is varied, we compute and analyze the escape rates of the system. Apart from very weak or strong interactions, the escape rates show consistently exponential behavior, thus suggesting strongly chaotic dynamics and a phase space without significant sticky regions within the considered time scales. (paper)
Renormalization of Coulomb interactions in a system of two-dimensional tilted Dirac fermions
Lee, Yu-Wen; Lee, Yu-Li
2018-01-01
We investigate the effects of long-ranged Coulomb interactions in a tilted Dirac semimetal in two dimensions by using the perturbative renormalization-group (RG) method. Depending on the magnitude of the tilting parameter, the undoped system can have either Fermi points (type I) or Fermi lines (type II). Previous studies usually performed the renormalization-group transformations by integrating out the modes with large momenta. This is problematic when the Fermi surface is open, like type-II Dirac fermions. In this work we study the effects of Coulomb interactions, following the spirit of Shankar [Rev. Mod. Phys. 66, 129 (1994), 10.1103/RevModPhys.66.129], by introducing a cutoff in the energy scale around the Fermi surface and integrating out the high-energy modes. For type-I Dirac fermions, our result is consistent with that of the previous work. On the other hand, we find that for type-II Dirac fermions, the magnitude of the tilting parameter increases monotonically with lowering energies. This implies the stability of type-II Dirac fermions in the presence of Coulomb interactions, in contrast with previous results. Furthermore, for type-II Dirac fermions, the velocities in different directions acquire different renormalization even if they have the same bare values. By taking into account the renormalization of the tilting parameter and the velocities due to the Coulomb interactions, we show that while the presence of a charged impurity leads only to charge redistribution around the impurity for type-I Dirac fermions, for type-II Dirac fermions, the impurity charge is completely screened, albeit with a very long screening length. The latter indicates that the temperature dependence of physical observables are essentially determined by the RG equations we derived. We illustrate this by calculating the temperature dependence of the compressibility and specific heat of the interacting tilted Dirac fermions.
One-loop renormalization of Coulomb-gauge QED
International Nuclear Information System (INIS)
Adkins, G.S.
1983-01-01
In this article I present a physically motivated renormalization scheme for Coulomb-gauge QED. This scheme is useful in calculations involving QED bound states. I implement this scheme to one loop by calculating the electron self-energy, the electron self-mass, and the renormalization constants Z 1 and Z 2 . Formulas for the dimensional regularization of some noncovariant integrals useful in one-loop Coulomb-gauge calculations are given
On the vacuum structure in the Coulomb and Landau gauges
International Nuclear Information System (INIS)
Niemi, Antti.
1980-01-01
Vacuum structure in the SU(N) Coulomb and Landau gauges is studied by using the methods of harmonic maps. The asymptotic conditions at infinity have been declared and a systematic way to solve the Gribov vacuum copy equation is presented. Many examples are given both in the SU(N) Coulomb and Landau gauges as applications of the method. Finally, the physical interpretation of Gribov ambiguities is discussed. (author)
Kinetic theory for strongly coupled Coulomb systems
Dufty, James; Wrighton, Jeffrey
2018-01-01
The calculation of dynamical properties for matter under extreme conditions is a challenging task. The popular Kubo-Greenwood model exploits elements from equilibrium density-functional theory (DFT) that allow a detailed treatment of electron correlations, but its origin is largely phenomenological; traditional kinetic theories have a more secure foundation but are limited to weak ion-electron interactions. The objective here is to show how a combination of the two evolves naturally from the short-time limit for the generator of the effective single-electron dynamics governing time correlation functions without such limitations. This provides a theoretical context for the current DFT-related approach, the Kubo-Greenwood model, while showing the nature of its corrections. The method is to calculate the short-time dynamics in the single-electron subspace for a given configuration of the ions. This differs from the usual kinetic theory approach in which an average over the ions is performed as well. In this way the effective ion-electron interaction includes strong Coulomb coupling and is shown to be determined from DFT. The correlation functions have the form of the random-phase approximation for an inhomogeneous system but with renormalized ion-electron and electron-electron potentials. The dynamic structure function, density response function, and electrical conductivity are calculated as examples. The static local field corrections in the dielectric function are identified in this way. The current analysis is limited to semiclassical electrons (quantum statistical potentials), so important quantum conditions are excluded. However, a quantization of the kinetic theory is identified for broader application while awaiting its detailed derivation.
Energy Technology Data Exchange (ETDEWEB)
Bagraev, N. T., E-mail: Bagraev@mail.ioffe.ru [Ioffe Institute (Russian Federation); Chaikina, E. I. [Centro de Investigacion Cientifica y de Educacion Superior de Ensenada, Division de Fisica Aplicada (Mexico); Danilovskii, E. Yu.; Gets, D. S.; Klyachkin, L. E.; L’vova, T. V.; Malyarenko, A. M. [Ioffe Institute (Russian Federation)
2016-04-15
The sulfur passivation of the semi-insulating GaAs bulk (SI GaAs) grown in an excess phase of arsenic is used to observe the transition from the Coulomb blockade to the weak localization regime at room temperature. The I–V characteristics of the SI GaAs device reveal nonlinear behavior that appears to be evidence of the Coulomb blockade process as well as the Coulomb oscillations. The sulfur passivation of the SI GaAs device surface results in enormous transformation of the I–V characteristics that demonstrate the strong increase of the resistance and Coulomb blockade regime is replaced by the electron tunneling processes. The results obtained are analyzed within frameworks of disordering SI GaAs surface that is caused by inhomogeneous distribution of the donor and acceptor anti-site defects which affects the conditions of quantum- mechanical tunneling. Weak localization processes caused by the preservation of the Fermi level pinning are demonstrated by measuring the negative magnetoresistance in weak magnetic fields at room temperature. Finally, the studies of the magnetoresistance at higher magnetic fields reveal the h/2e Aharonov–Altshuler–Spivak oscillations with the complicated behavior due to possible statistical mismatch of the interference paths in the presence of different microdefects.
International Nuclear Information System (INIS)
Hoffmann, B.
1984-07-01
In three chapters different physical situations are described which have commonly the Coulomb interaction as driving force. The first two chapters study the Coulomb interactions in connection with the excitation of inner electron shells and the Coulomb excitation of nuclei in first order. In the third part on effect ofthe Coulomb interaction between electronic shell and nucleus is treated in second order (nuclear polarization), and its effect on the isotopic and isomeric shift is studied. (orig./HSI) [de
Premature conclusions about psychotherapy for dysthymia
Cuijpers, P.
2009-01-01
Dr Cuijpers and Colleagues Reply To the Editor: We thank Dr Gaudiano and colleagues for their contribution to the discussion about psychotherapy for dysthymia. We agree very much with Gaudiano et al that we should be careful about drawing definite conclusions about the comparative efficacy of
Results and conclusion; Resultados e conclusoes
Energy Technology Data Exchange (ETDEWEB)
NONE
2009-10-15
This chapter shows the results and conclusions of the ordered studies by the Science and Technology Ministry from Brazil to the Center of Management and Strategic Studies (CGEE), executed by a multidisciplinary team, most of UNICAMP - State University of Campinas, SP - for evaluation of Brazilian capacity and potential in the production of fuel bioethanol.
Data, model, conclusion, doing it again
Molenaar, W.
1998-01-01
This paper explores the robustness of conclusions from a statistical model against variations in model choice (rather than variations in random sampling and random assignment to treatments, which are the usual variations covered by inferential statistics). After the problem formulation in section 1,
Dynamic stresses, coulomb failure, and remote triggering: corrected
Hill, David P.
2012-01-01
Dynamic stresses associated with crustal surface waves with 15–30 s periods and peak amplitudes frictional strength threshold offer one explanation for instances of rapid‐onset triggered seismicity that develop during the surface‐wave peak dynamic stressing. Evaluation of the triggering potential of surface‐wave dynamic stresses acting on critically stressed faults using a Mohr’s circle representation together with the Coulomb failure criteria indicates that Love waves should have a higher triggering potential than Rayleigh waves for most fault orientations and wave incidence angles. That (1) the onset of triggered seismicity often appears to begin during the Rayleigh wave rather than the earlier arriving Love wave, and (2) Love‐wave amplitudes typically exceed those for Rayleigh waves suggests that the explanation for rapid‐onset dynamic triggering may not reside solely with a simple static‐threshold friction mode. The results also indicate that normal faults should be more susceptible to dynamic triggering by 20‐s Rayleigh‐wave stresses than thrust faults in the shallow seismogenic crust (<10 km) while the advantage tips in favor of reverse faults greater depths. This transition depth scales with wavelength and coincides roughly with the transition from retrograde‐to‐prograde particle motion. Locally elevated pore pressures may have a role in the observed prevalence of dynamic triggering in extensional regimes and geothermal/volcanic systems. The result is consistent with the apparent elevated susceptibility of extensional or transtensional tectonic regimes to remote triggering by Rayleigh‐wave dynamic stresses than compressional or transpressional regimes.
Power and Democracy in Denmark. Conclusions
DEFF Research Database (Denmark)
Andersen, Jørgen Goul; Christiansen, Peter Munk; Beck Jørgensen, Torben
In 1997, the Danish Parliament decided to launch a power study, officially An Analysis of Democracy and Power in Denmark. A steering committee consisting of five independent researchers was assigned responsibility for the project. The Steering Committee has gathered the overall conclusions from...... the numerous projects under the Power Study, and this book is a short presentation of these conclusions.The main focus of the book is the state of democracy in Denmark at the dawn of the 21st century. How has democracy fared, has the development made things better or worse, and to which extent does...... contemporary democracy live up to our democratic ideals? The answer is that in many ways democracy is doing better than we might have expected, considering the intense pressure on the nation state and the democratic institutions in the postwar period. The Danish population is still full of democratic life...
D3.7 Africa: Conclusion Report
DEFF Research Database (Denmark)
Mandrup, Thomas
2017-01-01
This report draws together information and analyses from the preceding eight reports of IECEU Work Package 3 that examine the effectiveness of EU civilian crisis management operations in Libya, South Sudan, CAR and DR. Congo. The four cases are examined in separate sections. The following is based...... on the findings in the eight previous deliverables, and pools together the conclusions from these previous eight deliverables in WP3....
Intershell resistance in multiwall carbon nanotubes: A Coulomb drag study
DEFF Research Database (Denmark)
Lunde, Anders Mathias; Flensborg, Karsten; Jauho, Antti-Pekka
2005-01-01
We calculate the intershell resistance R-21 in a multiwall carbon nanotube as a function of temperature T and Fermi level epsilon(F) (e.g., a gate voltage), varying the chirality of the inner and outer tubes. This is done in a so-called Coulomb drag setup, where a current I-1 in one shell induces...... effects for the Coulomb drag between different tubes due to selection rules combined with mismatching of wave vector and crystal angular momentum conservation near the Fermi level. This gives rise to orders of magnitude changes in R-21 and even the sign of R-21 can change depending on the chirality...
Vibrational motions in rotating nuclei studied by Coulomb excitations
Energy Technology Data Exchange (ETDEWEB)
Shimizu, Yoshifumi R. [Kyushu Univ., Fukuoka (Japan). Dept. of Physics
1998-03-01
As is well-known Coulomb excitation is an excellent tool to study the nuclear collective motions. Especially the vibrational excitations in rotating nuclei, which are rather difficult to access by usual heavy-ion fusion reactions, can be investigated in detail. Combined with the famous 8{pi}-Spectrometer, which was one of the best {gamma}-ray detector and had discovered some of superdeformed bands, such Coulomb excitation experiments had been carried out at Chalk River laboratory just before it`s shutdown of physics division. In this meeting some of the experimental data are presented and compared with the results of theoretical investigations. (author)
Phase-function method for Coulomb-distorted nuclear scattering
Energy Technology Data Exchange (ETDEWEB)
Sett, G.C.; Laha, U.; Talukdar, B.
1988-09-21
The phase-function method is very effective in treating quantum mechanical scattering problems for short-range local potentials. We adapt the phase method to deal with Coulomb plus Graz non-local separable potentials and derive a closed-form expression for the scattering phase shift. Our approach to the problem circumvents in a rather natural way the typical difficulties of incorporating the Coulomb interaction in a nuclear phase-shift calculation. We demonstrate the usefulness of our constructed expression by means of a model calculation.
Bose-Einstein interferometry and the Coulomb corrections
International Nuclear Information System (INIS)
Erazmus, B.; Lednicky, R; Lyuboshitz, V.; Martin, L.; Mikhailov, V.; Pluta, J.; Sinyukov, Y.; Stavinky, A.
1997-01-01
Two different methods are currently used to unfold the effects of the Coulomb interaction from the experimental correlation functions. Both the Gamow corrections and the method based on correlation function of opposite charge particles fail to reproduce exact calculations of Bose-Einstein correlation functions for two-pion and two-kaon pairs. The Gamow correction is a currently used technique by the physicists' community of ultra-relativistic heavy ions aiming at the deconvolution of the Coulomb interaction effects so allowing the occurrence of only the quantum statistics effects in the correlation functions.An improved formulation of the Gamow correction is presented which gives good agreements with the correct calculations
Nuclear fusion induced by Coulomb explosion of heteronuclear clusters.
Last, I; Jortner, J
2001-07-16
We propose a new mechanism for the production of high-energy ( E>3 keV) deuterons, suitable to induce dd nuclear fusion, based on multielectron ionization and Coulomb explosion of heteronuclear deuterium containing molecular clusters, e.g., (D2O)n, in intense ( 10(16)-2x10(18) W/cm2) laser fields. Cluster size equations for E, in conjunction with molecular dynamics simulations, reveal important advantages of Coulomb explosion of (D2O)n heteronuclear clusters, as compared with (D)n clusters. These involve the considerably increased D+ kinetic energy and a narrow, high-energy distribution of deuterons.
Coulomb breakup of 31Ne using finite range DWBA
International Nuclear Information System (INIS)
Shubhchintak; Chatterjee, R.
2013-01-01
Coulomb breakup of nuclei away from the valley of stability have been one of the most successful probes to unravel their structure. However, it is only recently that one is venturing into medium mass nuclei like 23 O and 31 Ne. This is a very new and exciting development which has expanded the field of light exotic nuclei to the deformed medium mass region. In this contribution, an extension of the previously proposed theory of Coulomb breakup within the post-form finite range distorted wave Born approximation to include deformation of the projectile is reported
Surficial uranium deposits: summary and conclusions
International Nuclear Information System (INIS)
Otton, J.K.
1984-01-01
Uranium occurs in a variety of surficial environments in calcretes, gypcretes, silcretes, dolocretes and in organic sediments. Groundwater moving on low gradients generates these formations and, under favourable circumstances, uranium deposits. A variety of geomorphic settings can be involved. Most surficial deposits are formed in desert, temperate wetland, tropical, or transitional environments. The largest deposits known are in sedimentary environments in arid lands. The deposits form largely by the interaction of ground or surface waters on the geomorphic surface in favourable geologic terrains and climates. The deposits are commonly in the condition of being formed or reconstituted, or being destroyed. Carnotite is common in desert deposits while in wetland deposits no uranium minerals may be seen. Radioactive disequilibrium is common, particularly in wetland deposits. Granites and related rocks are major source rocks and most large deposits are in regions with enriched uranium contents, i.e. significantly greater than 5 ppm uranium. Uranium dissolution and transport is usually under oxidizing conditions. Transport in desert conditions is usually as a bicarbonate. A variety of fixation mechanisms operate to extract the uranium and form the deposits. Physical barriers to groundwater flow may initiate ore deposition. Mining costs are likely to be low because of the near surface occurrence, but there may be processing difficulties as clay may be present and the saline or carbonate content may be high. (author)
Superiority in value and the repugnant conclusion
DEFF Research Database (Denmark)
Jensen, Karsten Klint
2007-01-01
superiority does not amount to a radical value difference at all. I then spell out the consequences of these results for different interpretations of Griffin's suggestion regarding population ethics. None of them comes out very successful, but perhaps they nevertheless retain some interest.......James Griffin has considered a weak form of superiority in value a possible remedy to the Repugnant Conclusion. In this paper, I demonstrate that, in a context where value is additive, this weaker form collapses into a stronger form of superiority. And in a context where value is non-additive, weak...
Cults and mental health: clinical conclusions.
Levine, S V
1981-12-01
The field of cults and their relation to psychological and psychiatric disorder is reft with rhetoric and opinion. There has been a particular dearth of documentation and substantiated data supporting psychiatric opinion. As a result of considerable research, clinical work, and an extensive literature review, certain conclusions or strongly suggested positions are enunciated. An attempt is made to substantiate each of the ten assertions based on existing data, in the hope that they will clarify the muddy existing data, area, make clinical positions and interventions more soundly based, and inspire debate and heuristic efforts.
Epistemology applied to conclusions of expert reports.
Lucena-Molina, Jose-Juan
2016-07-01
It is believed that to build a robust reasoning logic to make probabilistic inferences in forensic science from a merely mathematical or logistical viewpoint is not enough. Mathematical logic is the positive science of reasoning and as for that it is only interested in the positive calculus of its validity, regardless any prior ontological assumption. But without a determined ontology and epistemology which imply to define the concepts that they will use, it seems difficult that the proposed scientifically correct mathematical solution be successful as a European standard for making conclusions in forensic reports because it has to be based on judicial language. Forensic experts and Courts are not interested in the development of a positive science but in a practical science: in clarifying whether certain known facts are related to a possible crime. Therefore, not only the coherence of the demonstrative logic reasoning used (logic of propositions) is important, but also the precision of the concepts used by language and consistency among them in reasoning (logic of concepts). There is a linguistic level essential for a successful communication between the forensic practitioner and the Court which is mainly related, in our opinion, to semantics and figures of speech. The first one is involved because words used in forensic conclusions often have different meanings - it is said that they are polysemic - and the second one because there is often metonymy as well. Besides, semantic differences among languages regarding words with the same etymological root add another difficulty for a better mutual understanding. The two main European judicial systems inherit a wide and deep culture related to evidence in criminal proceedings and each of them has coined their own terminology but there are other two more abstract levels such as logical and epistemological, where we can find solid arguments by which terms used at legal level on conclusions of forensic reports could be
Coulomb repulsion in (TMTSF)2X and (TMTTF)2X
DEFF Research Database (Denmark)
Mortensen, Kell; Engler, E. M.
1985-01-01
On the basis of studies of transport properties of (TMTSF)2 X, (TMTTF)2X and their binary alloys the authors discuss the role of on-site Coulomb repulsion relative to the transfer integrals. In TMTTF-salts U/ta are believed to be large, resulting in a Hubbard gap, whereas U/ta in TMTSF...
Relation between the Fukui function and the Coulomb hole
Indian Academy of Sciences (India)
Unknown
EEM5 where E(N) is a quadratic interpolation of the values of the energy at integer N. EEM uses a coarse- grain representation of the molecular electronic den- sity in which ρ(r) is represented by non-overlapping spherical atomic densities centered at the nuclei po- sitions interacting with each other via the Coulomb.
Asymptotic coulombic conditions in the electron capture process
International Nuclear Information System (INIS)
Corchs, S.E.; Maidagan, J.M.; Rivarola, R.D.
1990-01-01
Several first order perturbative approximations of the transition amplitude for electronic capture are studied. Different models in which the long range Coulomb potential is represented by different internuclear dependent phases, in the initial and final wave functions, are analysed and compared. (Author). 8 refs., 2 figs
Structure of light neutron-rich nuclei through Coulomb dissociation
Indian Academy of Sciences (India)
Home; Journals; Pramana – Journal of Physics; Volume 57; Issue 2-3. Structure of light neutron-rich nuclei through Coulomb dissociation. U Datta Pramanik T Aumann D Cortina H Emling H Geissel M Hellström R Holzmann N Iwasa Y Leifels G Münzenberg M Rejmund C Scheidenberger K Sümmerer A Leistenschneider ...
Spontaneous breakdown of PT symmetry in the complex Coulomb ...
Indian Academy of Sciences (India)
Keywords. Spontaneous breakdown of PT symmetry; Coulomb potential; complex en- ergy eigenvalues. PACS Nos 03.65.Ge; 03.65.Nk; 11.30.Er. 1. Introduction. One of the most intriguing features of PT -symmetric quantum mechanics is the spontaneous breakdown of PT symmetry. This phenomenon was noted in the first.
Renormalizable Non-Covariant Gauges and Coulomb Gauge Limit
Baulieu, L
1999-01-01
To study ``physical'' gauges such as the Coulomb, light-cone, axial or temporal gauge, we consider ``interpolating'' gauges which interpolate linearly between a covariant gauge, such as the Feynman or Landau gauge, and a physical gauge. Lorentz breaking by the gauge-fixing term of interpolating gauges is controlled by extending the BRST method to include not only the local gauge group, but also the global Lorentz group. We enumerate the possible divergences of interpolating gauges, and show that they are renormalizable, and we show that the expectation value of physical observables is the same as in a covariant gauge. In the second part of the article we study the Coulomb-gauge as the singular limit of the Landau-Coulomb interpolating gauge. We find that unrenormalized and renormalized correlation functions are finite in this limit. We also find that there are finite two-loop diagrams of ``unphysical'' particles that are not present in formal canonical quantization in the Coulomb gauge. We verify that in the ...
Structure of light neutron-rich nuclei through Coulomb dissociation
Indian Academy of Sciences (India)
O, the low-lying E1 strength amounts up to about 12% of the energy weighted dipole sum rule strength depending on neutron excess. The cluster sum rule limit with. ½. O as a core is almost exhausted for. ½,½. O, while for more neutron rich isotopes the strength with respect to that limit decreases. Keywords. Coulomb ...
Chaos in a coulombic muffin-tin potential
International Nuclear Information System (INIS)
Brandis, S.
1994-04-01
We study the two-dimensional classical scattering dynamics by a Muffin-Tin potential with 3 Coulomb singularities. A complete symbolic dynamics for the periodic orbits is derivd. The classical trajectories are shown to be hyperbolic everywhere in phase space and to carry no conjugate points. (orig.)
Coulomb plus strong interaction bound states - momentum space numerical solutions
International Nuclear Information System (INIS)
Heddle, D.P.; Tabakin, F.
1985-01-01
The levels and widths of hadronic atoms are calculated in momentum space using an inverse algorithm for the eigenvalue problem. The Coulomb singularity is handled by the Lande substraction method. Relativistic, nonlocal, complex hadron-nucleus interactions are incorporated as well as vacuum polarization and finite size effects. Coordinate space wavefunctions are obtained by employing a Fourier Bessel transformation. (orig.)
Generalized second-order Coulomb phase shift functions
International Nuclear Information System (INIS)
Rosendorff, S.
1982-01-01
Some specific properties and the evaluation of the generalized second-order Coulomb phase shift functions (two-dimensional integrals of four spherical cylinder functions) are discussed. The dependence on the three momenta k 1 ,k-bar,k 2 , corresponding to the final, intermediate, and initial states is illustrated
Molecular integrals for slater type orbitals using coulomb sturmians
DEFF Research Database (Denmark)
Avery, James Emil; Avery, John Scales
2014-01-01
The use of Slater type orbitals in molecular calculations is hindered by the slowness of integral evaluation. In the present paper, we introduce a method for overcoming this problem by expanding STO's in terms of Coulomb Sturmians, for which the problem of evaluating molecular integrals rapidly has...... been satisfactorily solved using methods based on the theory of hyperspherical harmonics....
COULN, a program for evaluating negative energy Coulomb functions
International Nuclear Information System (INIS)
Noble, C.J.; Thompson, I.J.
1984-01-01
Program COULN calculates exponentially decaying Whittaker functions, Wsub(K,μ)(z) corresponding to negative energy Coulomb functions. The method employed is most appropriate for parameter ranges which commonly occur in atomic and molecular asymptotic scattering problems using a close-coupling approximation in the presence of closed channels. (orig.)
C reaction from the Coulomb dissociation of C
Indian Academy of Sciences (India)
beam energy within the fully quantum mechanical distorted wave Born approximation formalism of breakup reactions .... [17] of this formalism to nuclear astrophysics was on the Coulomb dissociation of 9Li on. 534. Pramana ..... The approximation involves the replacement of del-operator by an effective local momentum, K(= ...
Coulomb collisional relaxation process of ion beams in magnetized plasmas
Nishimura, Y.
2010-01-01
An orbit following code is developed to calculate ion beam trajectories in magnetized plasmas. The equation of motion (the Newton's equation) is solved including the Lorentz force term and Coulomb collisional relaxation term. Furthermore, a new algorithm is introduced by applying perturbation method regarding the collision term as a small term. The reduction of computation time is suggested.
Limits to Electron Beam Emittance from Stochastic Coulomb Interactions
Energy Technology Data Exchange (ETDEWEB)
Coleman-Smith, Christopher; Padmore, Howard A.; Wan, Weishi
2008-08-22
Dense electron beams can now be generated on an ultrafast timescale using laser driven photo-cathodes and these are used for a range of applications from ultrafast electron defraction to free electron lasers. Here we determine a lower bound to the emittance of an electron beam limited by fundamental stochastic Coulomb interactions.
Coulomb explosion of methyl iodide clusters using giga watt laser ...
Indian Academy of Sciences (India)
Administrator
Abstract. Nanosecond laser-induced Coulomb explosion studies have been carried out for methyl iodide clusters at 532 and 563 nm under similar laser intensity (~5 × 10. 9. W/cm. 2. ) conditions. Multiply charged atomic ions of carbon and iodine having large kinetic energy (~ 100 s of eV) were observed in both the cases.
Plasmon-mediated Coulomb drag between graphene waveguides
DEFF Research Database (Denmark)
Shylau, Artsem A.; Jauho, Antti-Pekka
2014-01-01
We analyze theoretically charge transport in Coulomb coupled graphene waveguides (GWGs). The GWGs are defined using antidot lattices, and the lateral geometry bypasses many technological challenges of earlier designs. The drag resistivity ρD, which is a measure of the many-particle interactions...
Coulomb blockade due to quantum phase slips illustrated with devices
Hriscu, A.M.; Nazarov, Y.V.
2011-01-01
To illustrate the emergence of Coulomb blockade from coherent quantum phase-slip processes in thin superconducting wires, we propose and theoretically investigate two elementary setups, or devices. The setups are derived from the Cooper-pair box and Cooper-pair transistor, so we refer to them as the
Global Advisory Group: conclusions and recommendations.
1986-02-01
The conclusions and recommendations formulated for the global program by the 8th meeting of the Expanded Program on Immunization (EPI) Global Advisory Group, which took place during November 1985, are summarized. The Global Advisory Group recommends that, in furtherance of the Five-Point Action Program endorsed by the World Health Assembly in 1983, 3 general and 4 specific actions be taken by national immunization programs with the support of the World Health Organization (WHO) to accelerate EPI progress. These recommendations reflect optimism that the 1990 goal of reducing morbidity and mortality by providing immunization for all children of the world can be realized but also acknowledge that many fundamental problems of national program management remain to be resolved. The general actions are: to promote the achievement of the 1990 immunization goal at national and international levels through collaboration among ministries, organizations, and individuals in both the public and private sectors; to adopt a mix of complementary strategies for program acceleration; and to ensure that rapid increases in coverage can be sustained through mechanisms which strengthen th delivery of other primary health care interventions. The specific actions are as follows: to provide immunization at every contact point; to reduce dropout rates between 1st and last immunizations; to improve immunization services to the disadvantaged in urban areas; and to increase priority for the control of measles, poliomyelitis, and neonatal tetanus. The WHO and the UN International Children's Emergency Fund (UNICEF) have collaborated in support of the EPI since the early days of the program. The acceleration of national efforts heightens the importance of this collaboration, particularly at the national level. It may be further facilitated by the provision of policy guidance from global and regional levels, by WHO and UNICEF collaborative agreements at the regional level, and by country agreements
Charge-carrier dynamics and Coulomb effects in semiconductor tetrapods
International Nuclear Information System (INIS)
Mauser, Christian
2011-01-01
In this thesis the Coulomb interaction and its influence on localization effects and dynamics of charge carriers in semiconductor nanocrystals were studied. In the studied nanostructures it deals with colloidal tetrapod heterostructures, which consist of a cadmium selenide (CdSe) core and four tetraedrical grown cadmium sulfide (CdS) respectively cadmium telluride (CdTe) legs, which exhibit a type-I respectively type-II band transition. The dynamics and interactions were studied by means of photoluminescence (PL) and absorption measurements both on the ensemble and on single nanoparticles, as well as time-resolved PL and transient absorption spectroscopy. Additionally theoretical simulations of the wave-function distributions were performed, which are based on the effective-mass approximation. The special band structure of the CdSe/CdS tetrapods offers a unique possibility to study the Coulomb interaction. The flat conduction band in these heterostructures makes the electron via the Coulomb interaction sensitive to the localization position of the hole within the structure. The valence band has instead a potential maximum in the CdSe, which leads to a directed localization of the hole and the photoluminescence of the core. Polarization-resolved measurements showed hereby an anisotropy of the photoluminescence, which could be explained by means of simulations of the wave-function distribution with an asymmetry at the branching point. Charge-carrier localization occur mainly both in longer structures and in trap states in the CdS leg and can be demonstrated in form of a dual emission from a nanocrystal. The charge-carrier dynamics of electron and hole in tetrapods is indeed coupled by the Coulomb interaction, however it cannot be completely described in an exciton picture. The coupled dynamics and the Coulomb interaction were studied concerning a possible influence of the geometry in CdSe/CdS nanorods and compared with those of the tetrapods. The interactions of the
DEFF Research Database (Denmark)
Clausen, Johan; Andersen, Lars; Damkilde, Lars
2010-01-01
This paper compares calculation results obtained with the Mohr-Coulomb and Drucker-Prager material models. The models are implemented in a finite element code and the exact models are used, i.e. no rounding of yield surface corners or apices is performed. Results for both 2D and 3D calculations a...
Coulomb stress change of crustal faults in Japan for 21 years, estimated from GNSS displacement
Nishimura, T.
2017-12-01
Coulomb stress is one of the simplest index to show how the fault is close to a brittle failure (e.g., earthquake). Many previous studies used the Coulomb stress change (ΔCFS) to evaluate whether the fault approaches failure and successfully explained an earthquake triggered by previous earthquakes and volcanic sources. Most studies use a model of a half-space medium with given rheological properties, boundary conditions, dislocation, etc. to calculate ΔCFS. However, Ueda and Takahashi (2005) proposed to calculate DCFS directly from surface displacement observed by GNSS. There are 6 independent components of stress tensor in an isotropic elastic medium. On the surface of the half-space medium, 3 components should be zero because of no traction on the surface. This means the stress change on the surface is calculated from the surface strain change using Hooke's law. Although an earthquake does not occur on surface, the stress change on the surface may approximate that at a depth of a shallow crustal earthquake (e.g., 10 km) if the source is far from the point at which we calculate the stress change. We tested it by comparing ΔCFS from the surface displacement and that from elastic fault models for past earthquakes. We first estimate a strain change with a method of Shen et al.(1996 JGR) from surface displacement and then calculate ΔCFS for a targeted focal mechanism. Although ΔCFS in the vicinity of the source fault cannot be reproduced from the surface displacement, surface displacement gives a good approximation of ΔCFS in a region 50 km away from the source if the target mechanism is a vertical strike-slip fault. It suggests that GNSS observation can give useful information on a recent change of earthquake potential. We, therefore, calculate the temporal evolution of ΔCFS on active faults in southwest Japan from April 1996 using surface displacement at GNSS stations. We used parameters for the active faults used for evaluation of strong motion by the
Perspective: Coulomb fluids--weak coupling, strong coupling, in between and beyond.
Naji, Ali; Kanduc, Matej; Forsman, Jan; Podgornik, Rudolf
2013-10-21
We present a personal view on the current state of statistical mechanics of Coulomb fluids with special emphasis on the interactions between macromolecular surfaces, concentrating on the weak and the strong coupling limits. Both are introduced for a (primitive) counterion-only system in the presence of macroscopic, uniformly charged boundaries, where they can be derived systematically. Later we show how this formalism can be generalized to the cases with additional characteristic length scales that introduce new coupling parameters into the problem. These cases most notably include asymmetric ionic mixtures with mono- and multivalent ions that couple differently to charged surfaces, ions with internal charge (multipolar) structure and finite static polarizability, where weak and strong coupling limits can be constructed by analogy with the counterion-only case and lead to important new insights into their properties that cannot be derived by any other means.
Coulomb torque - a general theory for electrostatic forces in many-body systems
International Nuclear Information System (INIS)
Khachatourian, Armik V M; Wistrom, Anders O
2003-01-01
In static experiments that comprise three conducting spheres suspended by torsion wires and held at constant electric potential, a net angular displacement about their centres has been observed. We demonstrate that the observed rotation is consistent with Coulomb's law of electrical forces complemented by Gauss' surface integrals for electrical potential. Analysis demonstrates that electrostatic torque is the result of electrostatic forces acting on an asymmetric distribution of charges residing on the surfaces of the spheres. The asymptotic value for electrostatic torque is proportional to the inverse of the fourth power of separation distance with the rotation direction, up or down taken perpendicular to a plane passing through sphere centres, given explicitly by the equation for torque. The identification of electrostatic torque prompts further analysis of models of matter at all size scales where electrostatic forces are the dominant operative force
Coulomb and Nuclear Breakup at Low Energies: Scaling Laws
Directory of Open Access Journals (Sweden)
Hussein M. S.
2013-12-01
Full Text Available We report on a recent work on the low-energy behavior of the breakup cross section in so far as it has important role in the fusion of weakly bound and halo nuclei at near-barrier energies. We assess the way the nuclear component of this cross section scales with the target mass. In complete accord with previous finding at higher energies we verify that the low energy behavior of the breakup cross section for a given projectile and relative center of mass energy with respect to the Coulomb barrier height scales as the cubic root of the mass number of the target. Surprisingly we find that the Coulomb component of the breakup cross section at these low energies also obeys scaling, but with a linear dependence on the target charge. Our findings are important when planning for experiments involving these exotic nuclei.
Conductance of a proximitized nanowire in the Coulomb blockade regime
van Heck, B.; Lutchyn, R. M.; Glazman, L. I.
2016-06-01
We identify the leading processes of electron transport across finite-length segments of proximitized nanowires and build a quantitative theory of their two-terminal conductance. In the presence of spin-orbit interaction, a nanowire can be tuned across the topological transition point by an applied magnetic field. Due to a finite segment length, electron transport is controlled by the Coulomb blockade. Upon increasing of the field, the shape and magnitude of the Coulomb blockade peaks in the linear conductance are defined, respectively, by Andreev reflection, single-electron tunneling, and resonant tunneling through the Majorana modes emerging after the topological transition. Our theory provides the framework for the analysis of experiments with proximitized nanowires [such as reported in S. M. Albrecht et al., Nature (London) 531, 206 (2016), 10.1038/nature17162] and identifies the signatures of the topological transition in the two-terminal conductance.
Coulomb oscillations in three-layer graphene nanostructures
International Nuclear Information System (INIS)
Guettinger, J; Stampfer, C; Molitor, F; Graf, D; Ihn, T; Ensslin, K
2008-01-01
We present transport measurements on a tunable three-layer graphene single electron transistor (SET). The device consists of an etched three-layer graphene flake with two narrow constrictions separating the island from source and drain contacts. Three lateral graphene gates are used to electrostatically tune the device. An individual three-layer graphene constriction has been investigated separately showing a transport gap near the charge neutrality point. The graphene tunneling barriers show a strongly nonmonotonic coupling as a function of gate voltage indicating the presence of localized states in the constrictions. We show Coulomb oscillations and Coulomb diamond measurements proving the functionality of the graphene SET. A charging energy of ∼0.6 meV is extracted.
Structural phase transitions and topological defects in ion Coulomb crystals
Energy Technology Data Exchange (ETDEWEB)
Partner, Heather L. [Physikalisch-Technische Bundesanstalt, Braunschweig (Germany); Nigmatullin, Ramil [Institute of Quantum Physics, Ulm Univ., Ulm (Germany); Burgermeister, Tobias [Physikalisch-Technische Bundesanstalt, Braunschweig (Germany); Keller, Jonas [Physikalisch-Technische Bundesanstalt, Braunschweig (Germany); Pyka, Karsten [Physikalisch-Technische Bundesanstalt, Braunschweig (Germany); Plenio, Martin B. [Center for Integrated Quantum Science and Technology, Ulm Univ., Ulm, (Germany):Institute for Theoretical Physics, Ulm Univ.,Ulm, (Germany); Retzker, Alex [Racah Institute of Physics, The Hebrew University of Jerusalem, Givat Ram (Israel); Zurek, Wojciech Hubert [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); del Campo, Adolfo [Univ. of Massachusetts, Amherst, MA (United States). Dept. of Physics; Mehlstaubler, Tanja E. [Physikalisch-Technische Bundesanstalt, Braunschweig (Germany)
2014-11-19
We use laser-cooled ion Coulomb crystals in the well-controlled environment of a harmonic radiofrequency ion trap to investigate phase transitions and defect formation. Topological defects in ion Coulomb crystals (kinks) have been recently proposed for studies of nonlinear physics with solitons and as carriers of quantum information. Defects form when a symmetry breaking phase transition is crossed non-adiabatically. For a second order phase transition, the Kibble-Zurek mechanism predicts that the formation of these defects follows a power law scaling in the rate of the transition. We demonstrate a scaling of defect density and describe kink dynamics and stability. We further discuss the implementation of mass defects and electric fields as first steps toward controlled kink preparation and manipulation.
Coulomb and Nuclear Breakup at Low Energies: Scaling Laws
Hussein, M. S.; Gomes, P. R. S.; Lubian, J.; Canto, L. F.
2013-12-01
We report on a recent work on the low-energy behavior of the breakup cross section in so far as it has important role in the fusion of weakly bound and halo nuclei at near-barrier energies. We assess the way the nuclear component of this cross section scales with the target mass. In complete accord with previous finding at higher energies we verify that the low energy behavior of the breakup cross section for a given projectile and relative center of mass energy with respect to the Coulomb barrier height scales as the cubic root of the mass number of the target. Surprisingly we find that the Coulomb component of the breakup cross section at these low energies also obeys scaling, but with a linear dependence on the target charge. Our findings are important when planning for experiments involving these exotic nuclei.
An entropic form for NLFP with coulombic-like potential
Energy Technology Data Exchange (ETDEWEB)
Grassi, A., E-mail: agrassi@unict.it [Dipartimento di Scienze del Farmaco, Università di Catania, V.le A. Doria 6, 95125 Catania (Italy)
2012-01-30
Here it is proposed a new entropy form for which it is possible to obtain a stationary solution of the Non-Linear Fokker–Planck equation (NLFP) with coulombic-like potentials. The general properties of this new entropy form are shown and the results are compared with those obtained by other entropy forms. Finally, the behavior of the stationary solution in presence of two point charges is also shown. -- Highlights: ► In this Letter we have proposed a new form of entropy. ► Starting from this new entropy form a Non-Linear Fokker–Planck equation has been derived. ► The stationary solution of the Non-Linear Fokker–Planck equation is obtained by using an external coulombic-like potential. ► A comparison with other forms of entropies has been proposed in the case of a single or two point charges.
Spherical harmonic expansion of short-range screened Coulomb interactions
Energy Technology Data Exchange (ETDEWEB)
Angyan, Janos G [Laboratoire de Cristallographie et de Modelisation des Materiaux Mineraux et Biologiques, UMR 7036, CNRS-Universite Henri Poincare, BP 239, F-54506 Vandoeuvre-les-Nancy (France); Gerber, Iann [Laboratoire de Cristallographie et de Modelisation des Materiaux Mineraux et Biologiques, UMR 7036, CNRS-Universite Henri Poincare, BP 239, F-54506 Vandoeuvre-les-Nancy (France); Marsman, Martijn [Institut fuer Materialphysik and Center for Computational Materials Science, Universitaet Wien, Sensengasse 8, A-1090, Vienna (Austria)
2006-07-07
Spherical harmonic expansions of the screened Coulomb interaction kernel involving the complementary error function are required in various problems in atomic, molecular and solid state physics, like for the evaluation of Ewald-type lattice sums or for range-separated hybrid density functionals. A general analytical expression is derived for the kernel, which is non-separable in the radial variables. With the help of series expansions a separable approximate form is proposed, which is in close analogy with the conventional multipole expansion of the Coulomb kernel in spherical harmonics. The convergence behaviour of these expansions is studied and illustrated by the electrostatic potential of an elementary charge distribution formed by products of Slater-type atomic orbitals.
An infinite family of superintegrable deformations of the Coulomb potential
Energy Technology Data Exchange (ETDEWEB)
Post, Sarah [Centre de recherches mathematiques, CP 6128 succ. Centre-Ville, Montreal, QC H3C 3J7 (Canada); Winternitz, Pavel, E-mail: post@CRM.UMontreal.C, E-mail: wintern@CRM.UMontreal.C [Centre de recherches mathematiques and Departement de mathematiques et de statistique, CP 6128 succ. Centre-Ville, Montreal, QC H3C 3J7 (Canada)
2010-06-04
We introduce a new family of Hamiltonians with a deformed Kepler-Coulomb potential dependent on an indexing parameter k. We show that this family is superintegrable for all rational k and compute the classical trajectories and quantum wavefunctions. We show that this system is related, via coupling constant metamorphosis, to a family of superintegrable deformations of the harmonic oscillator given by Tremblay, Turbiner and Winternitz. In doing so, we prove that all Hamiltonians with an oscillator term are related by coupling constant metamorphosis to systems with a Kepler-Coulomb term, both on Euclidean space. We also look at the effect of the transformation on the integrals of the motion, the classical trajectories and the wavefunctions, and give the transformed integrals explicitly for the classical system. (fast track communication)
Unsafe Coulomb excitation of $^{240-244}Pu$
Wiedenhöver, I; Hackman, L; Ahmad, I; Greene, J P; Amro, H; Carpenter, M P; Nisius, D T; Reiter, P; Lauritsen, T; Lister, C J; Khoo, T L; Siem, S; Cizewski, J A; Seweryniak, D; Uusitalo, J; Macchiavelli, A O; Chowdhury, P; Seabury, E H; Cline, D; Wu, C Y
1999-01-01
The high spin states of /sup 240/Pu and /sup 244/Pu have been investigated with GAMMASPHERE at ATLAS, using Coulomb excitation with a /sup 208/Pb beam at energies above the Coulomb barrier. Data on a transfer channel leading to /sup 242/Pu were obtained as well. In the case of /sup 244/Pu, the yrast band was extended to 34h(cross), revealing the completed pi i/sub 13/2/ alignment, a "first" for actinide nuclei. The yrast sequence of /sup 242/Pu was also extended to higher spin and a similar backbend was delineated. In contrast, while the ground state band of /sup 240/Pu was measured up to the highest rotational frequencies ever reported in the actinide region (~300 keV), no sign of particle alignment was observed. (11 refs).
Langevin Representation of Coulomb Collisions for bi-Maxwellian Plasmas
Czech Academy of Sciences Publication Activity Database
Hellinger, Petr; Trávníček, Pavel M.
2010-01-01
Roč. 229, č. 14 (2010), s. 5432-5439 ISSN 0021-9991 R&D Projects: GA AV ČR IAA300420702; GA AV ČR IAA300420602 Institutional research plan: CEZ:AV0Z30420517 Keywords : Coulomb collisions * Langevin equation * Bi-Maxwellian distribution function * Stochastic differential equation Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 2.345, year: 2010 http://www.elsevier.com/locate/jcp
On Coulomb collisions in bi-Maxwellian plasmas
Czech Academy of Sciences Publication Activity Database
Hellinger, Petr; Trávníček, Pavel M.
2009-01-01
Roč. 16, č. 5 (2009), 054501/1-054501/4 ISSN 1070-664X R&D Projects: GA AV ČR IAA300420702 Institutional research plan: CEZ:AV0Z30420517; CEZ:AV0Z10030501 Keywords : Coulomb collisions * transport coefficients * bi-Maxwellian distribution function Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 2.475, year: 2009 http://link.aip.org/link/?PHPAEN/16/054501/1
Langevin representation of Coulomb collisions for bi-Maxwellian plasmas
Czech Academy of Sciences Publication Activity Database
Hellinger, Petr; Trávníček, Pavel M.
2010-01-01
Roč. 229, č. 14 (2010), s. 5432-5439 ISSN 0021-9991 Grant - others:Akademie věd - GA AV ČR(CZ) IAA300420702; Akademie věd - GA AV ČR(CZ) IAA300420602 Program:IA; IA Institutional research plan: CEZ:AV0Z10030501 Keywords : Coulomb collisions * Langevin equation * Bi-Maxwellian distribution function Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 2.345, year: 2010
Coulomb excitation at shell-closure N = 40
International Nuclear Information System (INIS)
Leenhardt, S.; Azaiez, F.; Sorlin, O.
1999-01-01
The structure of exotic nuclei can be investigated by Coulomb excitation of radioactive beams. The value of the energy of the first 2 + and its excitation probability B(E2) can improve our knowledge about collective modes of even-even nuclei. The search of new regions of deformation and shape coexistence is also a strong motivation. Recent experiments have been performed with GANIL/LISE3 facility, using the detector 'Chateau de Cristal'. (authors)
Full Coulomb collision operator in the moment expansion
International Nuclear Information System (INIS)
Ji, Jeong-Young; Held, Eric D.
2009-01-01
The full Coulomb collision operator and its moments including nonlinear terms are analytically calculated in the moment expansion. In coupling nonlinear terms, the product formula which expresses a product of two harmonic tensors as a series of single harmonic tensors is derived. The collision operators and moments are written in explicit formulas for arbitrary moments and for arbitrary temperature and mass ratios. These expressions easily reduce to formulas for the small mass-ratio approximation or for like species.
Sine-Gordon mean field theory of a Coulomb gas
Energy Technology Data Exchange (ETDEWEB)
Diehl, Alexandre; Barbosa, Marcia C.; Levin, Yan
1997-12-31
Full text. The Coulomb gas provides a paradigm for the study of various models of critical phenomena. In particular, it is well known that the two dimensional (2 D). Coulomb gas can be directly used to study the superfluidity transition in {sup 4} He films, arrays of Josephson junctions, roughening transition, etc. Not withstanding its versatility, our full understanding of the most basic model of Coulomb gas, namely an ensemble of hard spheres carrying either positive or negative charges at their center, is still lacking. It is now well accepted that at low density the two dimensional plasma of equal number of positive and negative particles undergoes a Kosterlitz-Thouless (KT) metal insulator transition. This transition is of an infinite order and is characterized by a diverging Debye screening length. As the density of particles increases, the validity of the KT theory becomes questionable and the possibility of the KT transition being replaced by some kind of first order discontinuity has been speculated for a long time. In this work sine-Gordon field theory is used to investigate the phase diagram of a neutral Coulomb gas. A variational mean-field free energy is constructed and the corresponding phase diagrams in two and three dimensions are obtained. When analyzed in terms of chemical potential, the sine-Gordon theory predicts the phase diagram topologically identical to the Monte Carlo simulations and a recently developed Debye-Huckel-Bjerrum theory. In 2D, we find that the infinite-order Kosterlitz-Thouless line terminates in a tricritical point, after which the metal-insulator transition becomes first order. However, when the transformation from chemical potential to the density is made the whole insulating phase is mapped onto zero density. (author)
Many-Body Coulomb Gauge Exotic and Charmed Hybrids
Llanes-Estrada, Felipe J.; Cotanch, Stephen R.
2000-01-01
Utilizing a QCD Coulomb gauge Hamiltonian with linear confinement specified by lattice, we report a relativistic many-body calculation for the light exotic and charmed hybrid mesons. The Hamiltonian successfully describes both quark and gluon sectors, with vacuum and quasiparticle properties generated by a BCS transformation and more elaborate TDA and RPA diagonalizations for the meson ($q\\bar{q}$) and glueball ($gg$) masses. Hybrids entail a computationally intense relativistic three quasipa...
A mean field approach to Coulomb blockade for a disordered ...
Indian Academy of Sciences (India)
CB is the energy price paid in adding an electron to a QD. Classically, this price is ≈e2/C, where e is the electron charge and C is the capacitance of the QD. In many-body quantum mechanics, this price is given a name, namely Hubbard U. The Coulomb blockade is the model led by an effective Hubbard U which in the.
Jung, Han Sae; Tsai, Hsin-Zon; Wong, Dillon; Germany, Chad; Kahn, Salman; Kim, Youngkyou; Aikawa, Andrew S; Desai, Dhruv K; Rodgers, Griffin F; Bradley, Aaron J; Velasco, Jairo; Watanabe, Kenji; Taniguchi, Takashi; Wang, Feng; Zettl, Alex; Crommie, Michael F
2015-07-24
Owing to its relativistic low-energy charge carriers, the interaction between graphene and various impurities leads to a wealth of new physics and degrees of freedom to control electronic devices. In particular, the behavior of graphene's charge carriers in response to potentials from charged Coulomb impurities is predicted to differ significantly from that of most materials. Scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS) can provide detailed information on both the spatial and energy dependence of graphene's electronic structure in the presence of a charged impurity. The design of a hybrid impurity-graphene device, fabricated using controlled deposition of impurities onto a back-gated graphene surface, has enabled several novel methods for controllably tuning graphene's electronic properties. Electrostatic gating enables control of the charge carrier density in graphene and the ability to reversibly tune the charge and/or molecular states of an impurity. This paper outlines the process of fabricating a gate-tunable graphene device decorated with individual Coulomb impurities for combined STM/STS studies. These studies provide valuable insights into the underlying physics, as well as signposts for designing hybrid graphene devices.
Optimal reconfigurations of two-craft Coulomb formations along manifolds
Jones, Drew R.; Schaub, Hanspeter
2013-02-01
Coulomb formations refer to swarms of closely flying spacecraft, in which the net electric charge of each vehicle is controlled. Active charge control is central to this concept and enables a propulsion system with highly desirable characteristics, albeit with limited controllability. Numerous Coulomb formation equilibria have been derived, but to maintain and maneuver these configurations, some inertial thrust is required to supplement the nearly propellant-less charge control. In this work, invariant manifold theory is applied to two-craft Coulomb equilibria, which are admitted in a linearized two-body gravity model. The manifolds associated with these systems are analyzed for the first time, and are then utilized as part of a general procedure for formulating optimal reconfigurations. Specifically, uncontrolled flows along the manifolds are sought which provide near continuous transfers from one equilibrium to another. Control is then introduced to match continuity, while minimizing inertial thrusting. This methodology aims to exploit uncontrolled motions and charge control to realize the shape-changing ability of these formations, without large inertial control efforts. Some variations in formulating and parameterizing the optimal transfers are discussed, and analytical expressions are derived to aid in establishing control parameter limits, under certain assumptions. Numerical results are provided, as demonstrative examples of the optimization procedure, using relatively simple control approximations. Finally, Particle Swarm Optimization, a novel stochastic method, is used with considerable success to solve the numerically difficult parameter optimization problems.
Analytic T matrices for Coulomb plus rational separable potentials
International Nuclear Information System (INIS)
van Haeringen, H.; van Wageningen, R.
1975-01-01
The l=0 partial wave projected Coulomb off-shell T matrix T/subc,l=0/ in momentum representation is obtained in closed form. Problems existing in the literature concerning the half- and on-shell behavior of T/subc/ and T/subc/,/subl/ are discussed and clarified by means of explicit formulas. The remaining derivations in this paper are based on T/subc,l=0/. We consider the class of N-term separable potentials where the form factors are rational functions of p 2 (in momentum representation). We prove that the l=0 T matrix corresponding to the Coulomb potential plus any such so-called rational separable potential has a very simple form, namely, it can be written in terms of rational functions and the (simple) hypergeometric function with parameters (1, iγ; 1+iγ), where γ is the well-known Coulomb parameter. Explicit analytic formulas are derived for a number of simple members of the class, the Yamaguchi potential being one of them. In this particular case the expressions of Zachary and of Bajzer are reproduced which used a method based on the O 4 symmetry
Engineering drag currents in Coulomb coupled quantum dots
Lim, Jong Soo; Sánchez, David; López, Rosa
2018-02-01
The Coulomb drag phenomenon in a Coulomb-coupled double quantum dot system is revisited with a simple model that highlights the importance of simultaneous tunneling of electrons. Previously, cotunneling effects on the drag current in mesoscopic setups have been reported both theoretically and experimentally. However, in both cases the sequential tunneling contribution to the drag current was always present unless the drag level position were too far away from resonance. Here, we consider the case of very large Coulomb interaction between the dots, whereby the drag current needs to be assisted by cotunneling events. As a consequence, a quantum coherent drag effect takes place. Further, we demonstrate that by properly engineering the tunneling probabilities using band tailoring it is possible to control the sign of the drag and drive currents, allowing them to flow in parallel or antiparallel directions. We also show that the drag current can be manipulated by varying the drag gate potential and is thus governed by electron- or hole-like transport.
Energy Technology Data Exchange (ETDEWEB)
Dasso, C.H. [Niels Bohr Inst., Copenhagen (Denmark); Guisado, J.L. [Niels Bohr Inst., Copenhagen (Denmark); Lenzi, S.M. [Niels Bohr Inst., Copenhagen (Denmark)]|[Padua Univ. (Italy). Dipt. di Fisica]|[Istituto Nazionale di Fisica Nucleare, Padua (Italy); Vitturi, A. [Padua Univ. (Italy). Dipt. di Fisica]|[Istituto Nazionale di Fisica Nucleare, Padua (Italy)
1996-02-05
We investigate the relative importance of the Coulomb and nuclear fields to induce the break-up of neutron-rich nuclei such as {sup 11}Li at energies close to the Coulomb barrier. We assume that the mechanism that leads to the separation is the excitation of a low-lying dipole mode in which the weakly-bound neutron halo performs a collective oscillation against the residual nuclear core. To this end we exploit semiclassical prescriptions that are adequate to calculate not only the average break-up probabilities but also to estimate the size of fluctuations about the quantal expectation values. Possible outcomes are explored as a function of both bombarding energy and impact parameter. Consequences of the couplings for elastic scattering and fusion processes are also discussed. (orig.).
Finite Element Analysis of the Amontons-Coulomb's Model using Local and Global Friction Tests
International Nuclear Information System (INIS)
Oliveira, M. C.; Menezes, L. F.; Ramalho, A.; Alves, J. L.
2011-01-01
In spite of the abundant number of experimental friction tests that have been reported, the contact with friction modeling persists to be one of the factors that determine the effectiveness of sheet metal forming simulation. This difficulty can be understood due to the nature of the friction phenomena, which comprises the interaction of different factors connected to both sheet and tools' surfaces. Although in finite element numerical simulations friction models are commonly applied at the local level, they normally rely on parameters identified based on global experimental tests results. The aim of this study is to analyze the applicability of the Amontons-Coulomb's friction coefficient identified using complementary tests: (i) load-scanning, at the local level and (ii) draw-bead, at the global level; to the numerical simulation of sheet metal forming processes.
Co-solvents with high coulombic efficiency in propylene carbonate based electrolytes
Liu, Gao; Zhao, Hui; Park, Sang-Jae
2017-06-27
A homologous series of cyclic carbonate or propylene carbonate (PC) analogue solvents with increasing length of linear alkyl substitutes were synthesized and used as co-solvents with PC for graphite based lithium ion half cells. A graphite anode reaches a capacity around 310 mAh/g in PC and its analogue co-solvents with 99.95% Coulombic efficiency. Cyclic carbonate co-solvents with longer alkyl chains are able to prevent exfoliation of graphite when used as co-solvents with PC. The cyclic carbonate co-solvents of PC compete for solvation of Li ion with PC solvent, delaying PC co-intercalation. Reduction products of PC on graphite surfaces via single-electron path form a stable Solid Electrolyte Interphase (SEI), which allows the reversible cycling of graphite.
Quantum Coulomb Systems: Recombination, Screening, and van der Waals Forces
International Nuclear Information System (INIS)
Alastuey, A.
2009-01-01
Under standard Earth conditions, and also in many astrophysical situations, the properties of matter result from the interplay between non-relativistic quantum mechanics and Coulomb interactions. In that context, the derivation of exact results for equilibrium properties of quantum Coulomb systems is of crucial importance. First, I briefly review rigorous proofs about either stability or limiting behaviours, as well as various asymptotic expansions specific to almost fully ionized situations. Then, I present the Feynman-Kac path integral representation which is the most efficient tool for dealing with both recombination and screening. Within that representation, the grand-canonical partition function for a system of quantum particles with two-body interactions is shown to be equal to its equivalent counterpart for a system of classical loops. Equilibrium quantities for the gas of loops are then represented by straightforward generalizations of standard Mayer diagrammatics. Because of the Coulomb-like long range of the two-body loop potential, every Mayer graph diverges. Such divergences are first removed via systematic chain resummations, which amount to introduce an effective potential φ, the quantum analogue of Debye potential. In a second step, the whole resumed diagrammatical series is exactly reorganized in terms of graphs where particle clusters are connected by bonds built with φ. The corresponding screened cluster representation is particularly useful for studying partially ionized gases, as illustrated by its application to hydrogen in the atomic regime. Exact asymptotic expansions for thermodynamics are derived beyond familiar Saha theory. Also, the screening of van der Waals forces between two hydrogen atoms by ionized protons and ionized electrons is shown to be only partial. (author)
Energy Technology Data Exchange (ETDEWEB)
Brogi, Bharat Bhushan, E-mail: brogi-221179@yahoo.in; Ahluwalia, P. K. [Department of Physics, Himachal Pradesh University, Shimla-171005 (India); Chand, Shyam [University Institute of Information Technology, H.P. University Shimla-171005 (India)
2015-06-24
Theoretical study of the Coulomb blockade effect on transport properties (Transmission Probability and I-V characteristics) for varied configuration of coupled quantum dot system has been studied by using Non Equilibrium Green Function(NEGF) formalism and Equation of Motion(EOM) method in the presence of magnetic flux. The self consistent approach and intra-dot Coulomb interaction is being taken into account. As the key parameters of the coupled quantum dot system such as dot-lead coupling, inter-dot tunneling and magnetic flux threading through the system can be tuned, the effect of asymmetry parameter and magnetic flux on this tuning is being explored in Coulomb blockade regime. The presence of the Coulomb blockade due to on-dot Coulomb interaction decreases the width of transmission peak at energy level ε + U and by adjusting the magnetic flux the swapping effect in the Fano peaks in asymmetric and symmetric parallel configuration sustains despite strong Coulomb blockade effect.
Coulomb Sturmians as a basis for molecular calculations
DEFF Research Database (Denmark)
Avery, John Scales; Avery, James Emil
2012-01-01
Almost all modern quantum chemistry programs use Gaussian basis sets even though Gaussians cannot accurately represent the cusp at atomic nuclei, nor can they represent the slow decay of the wave function at large distances. The reason that Gaussians dominate quantum chemistry today is the great...... mathematical difficulty of evaluating interelectron repulsion integrals when exponential-type orbitals (ETOs) are used. In this paper we show that when many-centre Coulomb Sturmian ETOs are used as a basis, the most important integrals can be evaluated rapidly and accurately by means of the theory...
Approximation for a Coulomb-Volkov solution in strong fields
Reiss, H. R.; Krainov, V. P.
1994-08-01
A simple analytical approximation is found for the wave function of an electron simultaneously exposed to a strong, circularly polarized plane-wave field and an atomic Coulomb potential. The approximation is valid when α0>>1, where α0 is the classical radius of motion of a free electron in the plane-wave field. This constraint is sufficiently mild at low frequencies that it makes possible a major extension of the lower bound of laser intensities for which Volkov-solution-based approximations are useful.
Quantum fluctuations and the single-junction Coulomb blockade
Energy Technology Data Exchange (ETDEWEB)
Girvin, S.M. (Department of Physics, Indiana University, Bloomington, IN (USA)); Glazman, L.I. (Institute of Microelectronics Technology and High Purity Materials, U.S.S.R. Academy of Science, Moscow District (U.S.S.R.)); Jonson, M. (Solid State Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN (USA)); Penn, D.R.; Stiles, M.D. (National Institute of Standards and Technology, Gaithersburg, MD (USA))
1990-06-25
We investigate the effect of quantum fluctuations on the Coulomb blockade in a single tunnel junction coupled to its environment by a transmission line of arbitrary impedance {ital Z}({omega}). The quantized oscillation modes of the transmission line are suddenly displaced when an electron tunnels through the junction. For small {ital Z} (relative to the quantum of resitance), a weak power-law zero-bias anomaly occurs associated with the infrared-divergent shakeup of low-frequency transmission-line modes. For large {ital Z}, the full blockade is recovered. Comparison with recent experiments is made.
Hadronic correction to Coulomb potential between quarks and diquark structure
Energy Technology Data Exchange (ETDEWEB)
Xin-Heng, Guo [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil); Xue-Qian, Li; Peng-Nian, Shen [Academia Sinica, Beijing, BJ (China). Inst. of High Energy Physics; Chuang, Wang [Nankai Univ., TJ (China). Dept. of Physics
1997-07-01
We have studied the hadronic correction from the background pion fields due to the chiral symmetry breaking to the Coulomb potential that governs the short-distance behavior of the interactions between the bound quarks. The background fields are associated with the constituent quark mass. We find a modified form which favors the diquark structure. We also roughly estimate an influence of this correction on the phase shifts in nucleon scattering and find that it may cause an extra middle range attraction between nucleons which is expected. (author) 17 refs., 4 figs.
Proton radiography, nuclear cross sections and multiple Coulomb scattering
Energy Technology Data Exchange (ETDEWEB)
Sjue, Sky K. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2015-11-04
The principles behind proton radiography including multiple Coulomb scattering are discussed for a purely imaginary square well nucleus in the eikonal approximation. It is found that a very crude model can reproduce the angular dependence of the cross sections measured at 24 GeV/c. The largest differences are ~3% for the 4.56 mrad data, and ~4% for the 6.68 mrad data. The prospect of understanding how to model deterministically high-energy proton radiography over a very large range of energies is promising, but it should be tested more thoroughly.
Nonlocal and nonlinear electrostatics of a dipolar Coulomb fluid.
Sahin, Buyukdagli; Ralf, Blossey
2014-07-16
We study a model Coulomb fluid consisting of dipolar solvent molecules of finite extent which generalizes the point-like dipolar Poisson-Boltzmann model (DPB) previously introduced by Coalson and Duncan (1996 J. Phys. Chem. 100 2612) and Abrashkin et al (2007 Phys. Rev. Lett. 99 077801). We formulate a nonlocal Poisson-Boltzmann equation (NLPB) and study both linear and nonlinear dielectric response in this model for the case of a single plane geometry. Our results shed light on the relevance of nonlocal versus nonlinear effects in continuum models of material electrostatics.
Ice limit of Coulomb gauge Yang-Mills theory
International Nuclear Information System (INIS)
Heinzl, T.; Ilderton, A.; Langfeld, K.; Lavelle, M.; McMullan, D.
2008-01-01
In this paper we describe gauge invariant multiquark states generalizing the path integral framework developed by Parrinello, Jona-Lasinio, and Zwanziger to amend the Faddeev-Popov approach. This allows us to produce states such that, in a limit which we call the ice limit, fermions are dressed with glue exclusively from the fundamental modular region associated with Coulomb gauge. The limit can be taken analytically without difficulties, avoiding the Gribov problem. This is illustrated by an unambiguous construction of gauge invariant mesonic states for which we simulate the static quark-antiquark potential.
Coulomb interactions via local dynamics: a molecular-dynamics algorithm
International Nuclear Information System (INIS)
Pasichnyk, Igor; Duenweg, Burkhard
2004-01-01
We derive and describe in detail a recently proposed method for obtaining Coulomb interactions as the potential of mean force between charges which are dynamically coupled to a local electromagnetic field. We focus on the molecular dynamics version of the method and show that it is intimately related to the Car-Parrinello approach, while being equivalent to solving Maxwell's equations with a freely adjustable speed of light. Unphysical self-energies arise as a result of the lattice interpolation of charges, and are corrected by a subtraction scheme based on the exact lattice Green function. The method can be straightforwardly parallelized using standard domain decomposition. Some preliminary benchmark results are presented
On low energy scattering theory with Coulomb potentials
International Nuclear Information System (INIS)
Gibson, A.G.
1985-09-01
The scattering length is a very useful characteristic of the scattering phenomena. But in the presence of a combined potential (e.g. in nuclear physics, when Coulomb, the polarization and the strong potentials are to be added), the analytical definition of the scattering length in not unambigous and strictly defined. This problem is discussed in detail, the various alternatives are examined and compared. A practical suggestion is given for the proper choice of the definition and for the calculation of scattering length. Numerical solutions of the Schroedinger equation are compared with the results of different definitions. Some questions of application to nuclear physics are discussed. (D.Gy.)
Normally ordered expansion of 3-dimensional bipartite Coulomb potential operator
Energy Technology Data Exchange (ETDEWEB)
Fan Hongyi [CCAST (World Laboratory), P.O. Box 8730, Beijing 100080 (China) and Department of Physics, Shanghai Jiao Tong University, Shanghai 200030 (China) and Department of Material Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026 (China)]. E-mail: fhym@ustc.edu.cn; Fu Liang [Special Class for the Gifted Young, University of Science and Technology of China, Hefei, Anhui 230026 (China)
2004-08-23
We derive the normally ordered expansion formula of bipartite Coulomb potential operator vertical bar R->{alpha}-R->{beta} vertical bar -1 by virtue of the method of integral within an ordered product of operators and the entangled state representation, where vertical bar R->{alpha}-R->{beta} vertical bar is the distance between two particles' positions. The new expansion formula provides convenience for calculating its coherent states' matrix elements. The normally ordered expansion of vertical bar R->{alpha}-R->{beta} vertical bar k, k>=-2, is also deduced.
Hadronic correction to Coulomb potential between quarks and diquark structure
International Nuclear Information System (INIS)
Xin-Heng, Guo; Xue-Qian, Li; Peng-Nian, Shen; Chuang, Wang
1997-07-01
We have studied the hadronic correction from the background pion fields due to the chiral symmetry breaking to the Coulomb potential that governs the short-distance behavior of the interactions between the bound quarks. The background fields are associated with the constituent quark mass. We find a modified form which favors the diquark structure. We also roughly estimate an influence of this correction on the phase shifts in nucleon scattering and find that it may cause an extra middle range attraction between nucleons which is expected. (author)
Enhanced population of side band of {sup 155}Gd in heavy-ion Coulomb excitation
Energy Technology Data Exchange (ETDEWEB)
Oshima, Masumi; Hayakawa, Takehito; Hatsukawa, Yuichi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment] [and others
1998-03-01
In the Coulomb excitation of {sup 155}Gd with heavy projectiles, {sup 32}S, {sup 58}Ni and {sup 90}Zr, unexpectedly large enhancement of a positive-parity side band has been observed. This enhancement could not be reproduced by a Coulomb-excitation calculation taking into account the recommended upper limits of E1 or E3 transitions, which are compiled in the whole mass region, and is proportional to the electric field accomplished in the Coulomb-scattering process. (author)
Shvetsov-Shilovski, N. I.; Lein, M.
2018-01-01
Using the semiclassical two-step model for strong-field ionization we investigate the interference structures emerging in strong-field photoelectron holography, taking into account the Coulomb potential of the atomic core. For every kind of the interference pattern predicted by the three-step model, we calculate the corresponding structure in the presence of the Coulomb field, showing that the Coulomb potential modifies the interference patterns significantly.
Przybytek, Michal; Helgaker, Trygve
2013-08-07
We analyze the accuracy of the Coulomb energy calculated using the Gaussian-and-finite-element-Coulomb (GFC) method. In this approach, the electrostatic potential associated with the molecular electronic density is obtained by solving the Poisson equation and then used to calculate matrix elements of the Coulomb operator. The molecular electrostatic potential is expanded in a mixed Gaussian-finite-element (GF) basis set consisting of Gaussian functions of s symmetry centered on the nuclei (with exponents obtained from a full optimization of the atomic potentials generated by the atomic densities from symmetry-averaged restricted open-shell Hartree-Fock theory) and shape functions defined on uniform finite elements. The quality of the GF basis is controlled by means of a small set of parameters; for a given width of the finite elements d, the highest accuracy is achieved at smallest computational cost when tricubic (n = 3) elements are used in combination with two (γ(H) = 2) and eight (γ(1st) = 8) Gaussians on hydrogen and first-row atoms, respectively, with exponents greater than a given threshold (αmin (G)=0.5). The error in the calculated Coulomb energy divided by the number of atoms in the system depends on the system type but is independent of the system size or the orbital basis set, vanishing approximately like d(4) with decreasing d. If the boundary conditions for the Poisson equation are calculated in an approximate way, the GFC method may lose its variational character when the finite elements are too small; with larger elements, it is less sensitive to inaccuracies in the boundary values. As it is possible to obtain accurate boundary conditions in linear time, the overall scaling of the GFC method for large systems is governed by another computational step-namely, the generation of the three-center overlap integrals with three Gaussian orbitals. The most unfavorable (nearly quadratic) scaling is observed for compact, truly three-dimensional systems
International Nuclear Information System (INIS)
Irgaziev, B.F.; Alt, E.O.; Mukhamedzhanov, A.M.
1999-01-01
The amplitude for the Coulomb breakup of a light nucleus in the field of a highly charged ion is considered in the framework of the distorted wave approach, with particular emphasis being laid on correctly taking into account the three-body Coulomb interactions in the final state. Numerical calculations have been performed for the double differential cross section for the reaction 208 Pb( 8 B, 7 Be p) 208 Pb. They clearly demonstrate the importance of long-range three-body Coulomb correlations in the astrophysically interesting regime when the ejectiles have extremely small relative energies. Refs. 9 (author)
Coulomb dissociation reactions on molybdenum isotopes for astrophysics applications
Energy Technology Data Exchange (ETDEWEB)
Ershova, Olga
2012-03-09
Within the present work, photodissociation reactions on {sup 100}Mo, {sup 93}Mo and {sup 92}Mo isotopes were studied by means of the Coulomb dissociation method at the LAND setup at GSI. As a result of the analysis of the present experiment, integrated Coulomb excitation cross sections of the {sup 100}Mo({gamma},n), {sup 100}Mo({gamma},2n), {sup 93}Mo({gamma},n) and {sup 92}Mo({gamma},n) reactions were determined. A second important topic of the present thesis is the investigation of the efficiency of the CsI gamma detector. The data taken with the gamma calibration sources shortly after the experiment were used for the investigation. In addition, a test experiment in refined conditions was conducted within the framework of this thesis. Numerous GEANT3 simulations of the detector were performed in order to understand various aspects of its performance. As a result, the efficiency of the detector was determined to be approximately a factor of 2 lower than the efficiency expected from the simulation. (orig.)
Unsafe Coulomb excitation of 240-244Pu
International Nuclear Information System (INIS)
Ahmad, I.; Amro, H.; Carpenter, M. P.; Chowdhury, P.; Cizewski, J.; Cline, D.; Greene, J. P.; Hackman, G.; Janssens, R. V. F.; Khoo, T. L.; Lauritsen, T.; Lister, C. J.; Macchiavelli, A. O.; Nisius, D. T.; Reiter, P.; Seabury, E. H.; Seweryniak, D.; Siem, S.; Uusitalo, J.; Wiedenhoever, I.; Wu, C. Y.
1999-01-01
The high spin states of 240 Pu and 244 Pu have been investigated with GAMMASPHERE at ATLAS, using Coulomb excitation with a 208 Pb beam at energies above the Coulomb barrier. Data on a transfer channel leading to 242 Pu were obtained as well. In the case of 244 Pu, the yrast band was extended to 34h b ar revealing the completed πi 13/2 alignment, a ''first'' for actinide nuclei. The yrast sequence of 242 Pu was also extended to higher spin and a similar backbend was delineated. In contrast, while the ground state band of 240 Pu was measured up to the highest rotational frequencies ever reported in the actinide region (approximately300 keV), no sign of particle alignment was observed. In this case, several observable such as the large B(E1)/B(E2) branching ratios in the negative parity band, and the vanishing energy staggering between the negative and positive parity bands suggest that the strength of octupole correlations increases with rotational frequency. These stronger correlations may well be responsible for delaying or suppressing the πi 13/2 particle alignment
Adaptive time-stepping Monte Carlo integration of Coulomb collisions
Särkimäki, K.; Hirvijoki, E.; Terävä, J.
2018-01-01
We report an accessible and robust tool for evaluating the effects of Coulomb collisions on a test particle in a plasma that obeys Maxwell-Jüttner statistics. The implementation is based on the Beliaev-Budker collision integral which allows both the test particle and the background plasma to be relativistic. The integration method supports adaptive time stepping, which is shown to greatly improve the computational efficiency. The Monte Carlo method is implemented for both the three-dimensional particle momentum space and the five-dimensional guiding center phase space. Detailed description is provided for both the physics and implementation of the operator. The focus is in adaptive integration of stochastic differential equations, which is an overlooked aspect among existing Monte Carlo implementations of Coulomb collision operators. We verify that our operator converges to known analytical results and demonstrate that careless implementation of the adaptive time step can lead to severely erroneous results. The operator is provided as a self-contained Fortran 95 module and can be included into existing orbit-following tools that trace either the full Larmor motion or the guiding center dynamics. The adaptive time-stepping algorithm is expected to be useful in situations where the collision frequencies vary greatly over the course of a simulation. Examples include the slowing-down of fusion products or other fast ions, and the Dreicer generation of runaway electrons as well as the generation of fast ions or electrons with ion or electron cyclotron resonance heating.
8B + 208Pb Elastic Scattering at Coulomb Barrier Energies
La Commara, M.; Mazzocco, M.; Boiano, A.; Boiano, C.; Manea, C.; Parascandolo, C.; Pierroutsakou, D.; Signorini, C.; Strano, E.; Torresi, D.; Yamaguchi, H.; Kahl, D.; Di Meo, P.; Grebosz, J.; Imai, N.; Hirayama, Y.; Ishiyama, H.; Iwasa, N.; Jeong, S. C.; Jia, H. M.; Kim, Y. H.; Kimura, S.; Kubono, S.; Lin, C. J.; Miyatake, H.; Mukai, M.; Nakao, T.; Nicoletto, M.; Sakaguchi, Y.; Sánchez-Benítez, A. M.; Soramel, F.; Teranishi, T.; Wakabayashi, Y.; Watanabe, Y. X.; Yang, L.; Yang, Y. Y.
2018-02-01
The scattering process of weakly-bound nuclei at Coulomb barrier energies provides deep insights on the reaction dynamics induced by exotic nuclei. Within this framework, we measured for the first time the scattering process of the short-lived Radioactive Ion Beam (RIB) 8B (Sp = 0.1375 MeV) from a 208Pb target at 50 MeV beam energy. The 8B RIB was produced by means of the in-flight facility CRIB (RIKEN, Japan) with an average intensity on target of 10 kHz and a purity about 25%. Elastically scattering ions were detected in the angular range θc.m. = 10°-160° by means of the detector array EXPADES. A preliminary optical model analysis indicates a total reaction cross section of about 1 b, a value, once reduced, 2-3 times larger than those obtained for the reactions induced by the stable weakly-bound projectiles 6,7Li on a 208Pb target in the energy range around the Coulomb barrier.
Coulomb Stress Accumulation along the San Andreas Fault System
Smith, Bridget; Sandwell, David
2003-01-01
Stress accumulation rates along the primary segments of the San Andreas Fault system are computed using a three-dimensional (3-D) elastic half-space model with realistic fault geometry. The model is developed in the Fourier domain by solving for the response of an elastic half-space due to a point vector body force and analytically integrating the force from a locking depth to infinite depth. This approach is then applied to the San Andreas Fault system using published slip rates along 18 major fault strands of the fault zone. GPS-derived horizontal velocity measurements spanning the entire 1700 x 200 km region are then used to solve for apparent locking depth along each primary fault segment. This simple model fits remarkably well (2.43 mm/yr RMS misfit), although some discrepancies occur in the Eastern California Shear Zone. The model also predicts vertical uplift and subsidence rates that are in agreement with independent geologic and geodetic estimates. In addition, shear and normal stresses along the major fault strands are used to compute Coulomb stress accumulation rate. As a result, we find earthquake recurrence intervals along the San Andreas Fault system to be inversely proportional to Coulomb stress accumulation rate, in agreement with typical coseismic stress drops of 1 - 10 MPa. This 3-D deformation model can ultimately be extended to include both time-dependent forcing and viscoelastic response.
Coulomb effects on pions produced in heavy-ion reactions
Energy Technology Data Exchange (ETDEWEB)
Sullivan, J.P.
1981-11-01
Double differential cross sections for the production of ..pi../sup +/ and ..pi../sup -/ near the velocity of the incident beam for pion lab angles less than 40 degrees are presented. The experimental apparatus and the techniques are discussed. Beams of /sup 20/Ne with E/A from 80 to 655 MeV and /sup 40/Ar with E/A = 535 MeV incident on Be, C, NaF, KC1, Cu, and U targets were used. A sharp peak in the ..pi../sup -/ spectrum and a depression in the ..pi../sup +/ spectrum were observed at zero degrees near the incident beam velocity. The effect is explained in terms of Coulomb interactions between the pions and fragments of the incident beam. Least squares fits to the data using the Coulomb correction formulas of Gyulassy and Kauffman and an effective projectile fragment charge are made. The relationship between these data and previously measured pion production and projectile fragmentation data is discussed. The data are also compared to some theoretical models. A simple expression is given for the differential cross section as a function of the projectile mass, target mass, and beam energy.
Frictional Sliding Along Coulombic Shear Faults in Ice
Fortt, A. L.; Schulson, E. M.
2006-12-01
There is increasing evidence that the processes underlying the deformation of the arctic sea ice cover are independent of spatial scale. Among them, and possibly the dominant one during winter, is frictional sliding. With the objective of characterizing and then understanding this process, we performed a series of sliding experiments along Coulombic shear faults that were created in the laboratory in both S2 freshwater ice and S2 first-year arctic sea ice. The principal variables were sliding velocity (4 × 10-3 m s-1 to 8 × 10-7 m s-1, temperature (-3 °C, -10 °C and -40 °C) and confinement (up to 2 MPa). The results show that in both materials Coulomb's failure criterion describes the relationship between the shear stress along the fault and the normal stress across it. The friction coefficient reaches a maximum at an intermediate velocity, at ~ 10-5 m s-1 for the fresh-water material and at ~ 10-4 s-1 for the sea ice, and it increases with decreasing temperature. We propose that at lower velocities where velocity-strengthening is observed, frictional resistance is governed by creep deformation within the damage zone that constitutes the fault, while at higher velocities additional fracture and frictional melting are at play.
Scattering amplitudes on the Coulomb branch of N=4 super Yang-Mills
International Nuclear Information System (INIS)
Henn, J.M.
2010-01-01
We discuss planar scattering amplitudes on the Coulomb branch of N=4 super Yang-Mills. The vacuum expectation values on the Coulomb branch can be used to regulate infrared divergences. We argue that this has a number of conceptual as well as practical advantages over dimensional regularisation.
On the role of deformed Coulomb potential in fusion using energy ...
Indian Academy of Sciences (India)
Abstract. Using the Skyrme energy density formalism, the effect of deformed Coulomb potential on fusion barriers and fusion cross-sections is studied. Our detailed study reveals that the fusion barriers as well as fusion probabilities depend on the shape deformation (due to deformed Coulomb potential) of the colliding nuclei ...
A Simple And Efficient FEM-Implementation Of The Modified Mohr-Coulomb Criterion
DEFF Research Database (Denmark)
Clausen, Johan Christian; Damkilde, Lars
2006-01-01
This paper presents a conceptually simple finite element implementation of the combined elasto-plastic Mohr-Coulomb and Rankine material models, also known as Modified Mohr-Coulomb plasticity. The stress update is based on a return mapping scheme where all manipulations are carried out in principal...
On the Coulomb sum rule in the relativistic nuclear many-body problem
International Nuclear Information System (INIS)
Matsui, T.
1983-01-01
It is shown that the relativistic many-body theory the Coulomb sum rule value is never exhausted in the space-like momentum transfer region. This implies that the Coulomb sum rule should be used with a particular caution to analyze deep inelastic electron scattering from nuclei. (orig.)
Coulomb blockade in turnstile with multiple tunnel junctions
Lee, S C; Kang, D S; Kim, D C; Choi, C K; Ryu, J Y
1999-01-01
On the basis of the analytic solutions to the electrostatic problem of the multi-grated-small-junction systems, the stable domain for the Coulomb blockade of turnstile with multiple tunnel junctions at zero temperature has been analyzed as a function of the number of tunnel junction, the ratio of the gate capacitance to the junction capacitance, and the asymmetric factor. Our results show that domains form various shaped regions according to the asymmetric factor and their size depends on the number of junction and the ratio of the gate capacitance to the junction capacitance. In particular, it is shown that electrons can be transferred in positive and/or negative bias voltage depending on the asymmetric factor when an appropriate gate cycle is applied. Thus, the asymmetric factor plays an important role in determining the turnstile operation.
Characteristic features of net information measures for constrained Coulomb potentials
International Nuclear Information System (INIS)
Patil, S H; Sen, K D; Watson, N A; Jr, H E Montgomery
2007-01-01
The dimensional analyses of the position and momentum variance based quantum mechanical Heisenberg uncertainty measure and the other useful net entropic information measures for the bound states of two constrained Coulomb potentials are reported for the first time. The potentials describe an electron moving in the central field due to a nucleus of charge Z with radius R defining the constraints as (a) the truncated potential given by -Z/(r n +R n ) 1/n , and (b) the radius of the impenetrable spherical wall. The net information measures for the two potentials are explicitly shown to be independent of the scaling of the set [Z, R] at a fixed value of ZR. Analytic proof is presented, for the first time, showing the presence of a characteristic extremum in the variation of the net information entropy as a function of the radius R with its location scaling as Z -1 . Numerical results are presented which support the validity of the scaling properties
Imaging of Coulomb-Driven Quantum Hall Edge States
Lai, Keji
2011-10-01
The edges of a two-dimensional electron gas (2DEG) in the quantum Hall effect (QHE) regime are divided into alternating metallic and insulating strips, with their widths determined by the energy gaps of the QHE states and the electrostatic Coulomb interaction. Local probing of these submicrometer features, however, is challenging due to the buried 2DEG structures. Using a newly developed microwave impedance microscope, we demonstrate the real-space conductivity mapping of the edge and bulk states. The sizes, positions, and field dependence of the edge strips around the sample perimeter agree quantitatively with the self-consistent electrostatic picture. The evolution of microwave images as a function of magnetic fields provides rich microscopic information around the ν=2 QHE state. © 2011 American Physical Society.
Ultra-high-ohmic microstripline resistors for Coulomb blockade devices
International Nuclear Information System (INIS)
Lotkhov, Sergey V
2013-01-01
In this paper, we report on the fabrication and low-temperature characterization of ultra-high-ohmic microstripline resistors made of a thin film of weakly oxidized titanium. Nearly linear voltage–current characteristics were measured at temperatures down to T ∼ 20 mK for films with sheet resistivities as high as ∼7 kΩ, i.e. about an order of magnitude higher than our previous findings for weakly oxidized Cr. Our analysis indicates that such an improvement can help to create an advantageous high-impedance environment for different Coulomb blockade devices. Further properties of the Ti film addressed in this work show the promise of low-noise behavior of the resistors when applied in different realizations of the quantum standard of current. (paper)
Coulomb and nuclear excitations of narrow resonances in 17Ne
Directory of Open Access Journals (Sweden)
J. Marganiec
2016-08-01
Full Text Available New experimental data for dissociation of relativistic 17Ne projectiles incident on targets of lead, carbon, and polyethylene targets at GSI are presented. Special attention is paid to the excitation and decay of narrow resonant states in 17Ne. Distributions of internal energy in the O15+p+p three-body system have been determined together with angular and partial-energy correlations between the decay products in different energy regions. The analysis was done using existing experimental data on 17Ne and its mirror nucleus 17N. The isobaric multiplet mass equation is used for assignment of observed resonances and their spins and parities. A combination of data from the heavy and light targets yielded cross sections and transition probabilities for the Coulomb excitations of the narrow resonant states. The resulting transition probabilities provide information relevant for a better understanding of the 17Ne structure.
Semiclassical asymptotic behavior and the rearrangement mechanisms for Coulomb particles
International Nuclear Information System (INIS)
Bogdanov, A.V.; Gevorkyan, A.S.; Dubrovskii, G.V.
1986-01-01
The semiclassical asymptotic behavior of the eikonal amplitude of the resonance rearrangement in a system of three Coulomb particles is studied. It is shown that the general formula for the amplitude correctly describes two classical mechanisms (pickup and knockout) and one nonclassical mechanism (stripping). The classical mechanisms predominate at high energies, while the stripping mechanism predominates at lower energies. In the region of medium energies the dominant mechanism is the pickup (or Thomas) mechanism, which is realized by nonclassical means. For such transitions the classical cross section diverges, and the amplitude must be computed on a complex trajectory. The physical reasons for introducing the approximate complex trajectories are discussed. The contributions of all the mechanisms to the rearrangement cross section are found in their analytic forms
Quantum Mayer Graphs: Application to Bose and Coulomb Gases
International Nuclear Information System (INIS)
Martin, P.A.
2003-01-01
The functional integral representation of quantum statistical mechanics by means of the Feynman-Kac formula leads to a classical-like description of the system. Point quantum particles are then described in terms of random loops (closed Brownian paths), and all techniques of classical statistical mechanics become available. One advantage of this formalism is that it is not perturbative with respect to the interaction strength, in contrast to the standard many-body perturbative treatment. We apply these ideas to the Coulomb gas by constructing an effective potential (the quantum analogue of the Debye potential) that incorporates both long distance collective screening effects as well as the short range quantum mechanical binding. For Bose systems, we show that mean field theory corresponds to summing all tree-graphs and investigate how to go beyond the mean field description. (author)
Ionization and Coulomb explosion of small uranium oxide clusters
International Nuclear Information System (INIS)
Ross, Matt W; Castleman, A W Jr
2012-01-01
Femtosecond pulses are used to study the strong-field ionization and subsequent Coulomb explosion of small uranium oxide clusters. The resulting high atomic charge states are explored as a function of laser intensity and compared to ionization rates calculated using semi-classical tunneling theory with sequential ionization potential values. The gap in laser intensity between saturation intensity values for the 7s, 6d, and 5f orbitals are identified and quantified. Extreme charge states of oxygen up to O 4+ are observed indicating multiple ionization enhancement processes occurring within the clusters. The peak splittings of the atomic charge states are explored and compared to previous results on transition metal oxide species. Participation of the 5f orbitals in bonding is clearly identified based on the saturation intensity dependence of oxygen to uranium metal.
Coulomb interaction effect in tilted Weyl fermion in two dimensions
Isobe, Hiroki; Nagaosa, Naoto
Weyl fermions with tilted linear dispersions characterized by several different velocities appear in some systems including the quasi-two-dimensional organic semiconductor α-(BEDT-TTF)2I3 and three-dimensional WTe2. The Coulomb interaction between electrons modifies the velocities in an essential way in the low energy limit, where the logarithmic corrections dominate. Taking into account the coupling to both the transverse and longitudinal electromagnetic fields, we derive the renormalization group equations for the velocities of the tilted Weyl fermions in two dimensions, and found that they increase as the energy decreases and eventually hit the velocity of light c to result in the Cherenkov radiation. Especially, the system restores the isotropic Weyl cone even when the bare Weyl cone is strongly tilted and the velocity of electrons becomes negative in certain directions.
Ultra-high-ohmic microstripline resistors for Coulomb blockade devices
Lotkhov, Sergey V.
2013-06-01
In this paper, we report on the fabrication and low-temperature characterization of ultra-high-ohmic microstripline resistors made of a thin film of weakly oxidized titanium. Nearly linear voltage-current characteristics were measured at temperatures down to T ˜ 20 mK for films with sheet resistivities as high as ˜7 kΩ, i.e. about an order of magnitude higher than our previous findings for weakly oxidized Cr. Our analysis indicates that such an improvement can help to create an advantageous high-impedance environment for different Coulomb blockade devices. Further properties of the Ti film addressed in this work show the promise of low-noise behavior of the resistors when applied in different realizations of the quantum standard of current.
Coulomb blockade transport across lateral (Ga,Mn)As nanoconstrictions
Schlapps, Markus; Geissler, Stefan; Lermer, Teresa; Sadowski, Janusz; Wegscheider, Werner; Weiss, Dieter
2010-09-01
We report on magnetotransport measurements of nanoconstricted (Ga,Mn)As devices showing very large resistance changes that can be controlled by both an electric and a magnetic field. Based on the bias voltage and temperature dependent measurements down to the millikelvin range we compare the models currently used to describe transport through (Ga,Mn)As nanoconstrictions. We provide an explanation for the observed spin-valve like behavior during a magnetic field sweep by means of the magnetization configurations in the device. Furthermore, we prove that Coulomb blockade plays a decisive role for the transport mechanism and show that modeling the constriction as a granular metal describes the temperature and bias dependence of the conductance correctly and allows to estimate the number of participating islands located in the constriction.
Coulomb breakup of nuclei-applications to astrophysics
International Nuclear Information System (INIS)
Baur, G.; Rebel, H.
1996-04-01
The Coulomb dissociation process, induced by the intense source of quasi-real photons acting as nuclear particles passing the field of a heavy nucleus, has attracted a great deal of attention. As specific application and access to information to the time-reversed radiative capture reactions of astrophysical interest at stellar energies, it provides several advantages based on larger cross sections and on the flexibilities of the breakup kinematics. Difficulties in the analysis arise from possible interference of nuclear interactions and final state effects through multiphoton exchange (post acceleration) which need careful consideration. Since the introduction of this novel approach as tool of nuclear astrophysics, a number of theoretical and experimental investigations have been performed, with interesting new information and results which provide an improved and detailed understanding of the experimental conditions and of the theoretical basis of the method. The progress in experiment and theory is reviewed, and various cases of actual interest and current applications are discussed. (orig.)
Investigation of uncertainty components in Coulomb blockade thermometry
Energy Technology Data Exchange (ETDEWEB)
Hahtela, O. M.; Heinonen, M.; Manninen, A. [MIKES Centre for Metrology and Accreditation, Tekniikantie 1, 02150 Espoo (Finland); Meschke, M.; Savin, A.; Pekola, J. P. [Low Temperature Laboratory, Aalto University, Tietotie 3, 02150 Espoo (Finland); Gunnarsson, D.; Prunnila, M. [VTT Technical Research Centre of Finland, Tietotie 3, 02150 Espoo (Finland); Penttilä, J. S.; Roschier, L. [Aivon Oy, Tietotie 3, 02150 Espoo (Finland)
2013-09-11
Coulomb blockade thermometry (CBT) has proven to be a feasible method for primary thermometry in every day laboratory use at cryogenic temperatures from ca. 10 mK to a few tens of kelvins. The operation of CBT is based on single electron charging effects in normal metal tunnel junctions. In this paper, we discuss the typical error sources and uncertainty components that limit the present absolute accuracy of the CBT measurements to the level of about 1 % in the optimum temperature range. Identifying the influence of different uncertainty sources is a good starting point for improving the measurement accuracy to the level that would allow the CBT to be more widely used in high-precision low temperature metrological applications and for realizing thermodynamic temperature in accordance to the upcoming new definition of kelvin.
Investigation of uncertainty components in Coulomb blockade thermometry
International Nuclear Information System (INIS)
Hahtela, O. M.; Heinonen, M.; Manninen, A.; Meschke, M.; Savin, A.; Pekola, J. P.; Gunnarsson, D.; Prunnila, M.; Penttilä, J. S.; Roschier, L.
2013-01-01
Coulomb blockade thermometry (CBT) has proven to be a feasible method for primary thermometry in every day laboratory use at cryogenic temperatures from ca. 10 mK to a few tens of kelvins. The operation of CBT is based on single electron charging effects in normal metal tunnel junctions. In this paper, we discuss the typical error sources and uncertainty components that limit the present absolute accuracy of the CBT measurements to the level of about 1 % in the optimum temperature range. Identifying the influence of different uncertainty sources is a good starting point for improving the measurement accuracy to the level that would allow the CBT to be more widely used in high-precision low temperature metrological applications and for realizing thermodynamic temperature in accordance to the upcoming new definition of kelvin
Effect of on-chip filter on Coulomb blockade thermometer
International Nuclear Information System (INIS)
Roschier, L; Penttilä, J S; Gunnarsson, D; Prunnila, M; Meschke, M; Savin, A
2012-01-01
Coulomb Blockade Thermometer (CBT) is a primary thermometer based on electric conductance of normal tunnel junction arrays. One limitation for CBT use at the lowest temperatures has been due to environmental noise heating. To improve on this limitation, we have done measurements on CBT sensors fabricated with different on-chip filtering structures in a dilution refrigerator with a base temperature of 10 mK. The CBT sensors were produced with a wafer scale tunnel junction process. We present how the different on-chip filtering schemes affect the limiting saturation temperatures and show that CBT sensors with proper on-chip filtering work at temperatures below 20 mK and are tolerant to noisy environment.
The Coulomb Branch Formula for Quiver Moduli Spaces
Manschot, Jan; Sen, Ashoke
2014-01-01
In recent series of works, by translating properties of multi-centered supersymmetric black holes into the language of quiver representations, we proposed a formula that expresses the Hodge numbers of the moduli space of semi-stable representations of quivers with generic superpotential in terms of a set of invariants associated to `single-centered' or `pure-Higgs' states. The distinguishing feature of these invariants is that they are independent of the choice of stability condition. Furthermore they are uniquely determined by the $\\chi_y$-genus of the moduli space. Here, we provide a self-contained summary of the Coulomb branch formula, spelling out mathematical details but leaving out proofs and physical motivations.
Coulomb effects in deuteron stripping reactions as a three-body problem
International Nuclear Information System (INIS)
Osman, A.
1981-08-01
Deuteron stripping nuclear reactions are reconsidered as a three-body problem. The Coulomb effects between the proton and the target nucleus are investigated. The mathematical formalism introduces three-body integral equations which can be exactly calculated for such simple models. These coupled integral equations suitably include the Coulomb effects due to replusive or attractive Coulomb potential. Numerical calculations of the differential cross-sections of the reactions 28 Si(d,p) 29 Si and 40 Ca(d,p) 41 Ca are carried out showing the importance of the Coulomb effects. The angular distributions of these reactions are theoretically calculated and fitted to the experimental data. From this fitting, reasonable spectroscopic factors are obtained. Inclusion of Coulomb force in the three-body model are found to improve the results by a percentage of about 6.826%. (author)
Waste Handling Shaft concrete liner degradation conclusions and recommendations
International Nuclear Information System (INIS)
1992-10-01
The primary function of the Waste Handling Shaft (WHS) at the Waste Isolation Pilot Plant (WIPP) is to permit the transfer of radioactive waste from the surface waste handling building to the underground storage area. It also serves as an intake shaft for small volumes of air during normal storage operations and as an emergency escape route. Part of the construction was the placement of a concrete liner and steel reinforced key in 1984. During a routine shaft inspection in May 1990, some degradation of the WHS concrete liner was observed between the depths of 800 and 900 feet below the ground surface. Detailed investigations of the liner had been carried out by Sandia National Laboratories and by Westinghouse Electric Corporation Waste Isolation Division (WID) through Lankard Materials Laboratory. Observations, reports, and data support the conclusion that the concrete degradation, resulting from attack by chemically aggressive brine, is a localized phenomena. It is the opinion of the WID that the degradation is not considered an immediate or near term concern; this is supported by technical experts. WID recommendations have been made which, when implemented, will ensure an extended liner life. Based on the current assessment of available data and the proposed shaft liner monitoring program described in this report, it is reasonable to assume that the operational life of the concrete shaft liner can safely support the 25-year life of the WIPP. Analysis of data indicates that degradation of the shaft's concrete liner is attributed to chemically aggressive brine seeping through construction joints and shrinkage cracks from behind the liner in and around the 834-foot depth. Chemical and mechanical components of concrete degradation have been identified. Chemical attack is comprised of several stages of concrete alteration. The other component, mechanical degradation, results from the expansive forces of crystals forming in the concrete pore space
Quasi-stationary states and fermion pair creation from a vacuum in supercritical Coulomb field
Khalilov, V. R.
2017-12-01
Creation of charged fermion pair from a vacuum in so-called supercritical Coulomb potential is examined for the case when fermions can move only in the same (one) plane. In which case, quantum dynamics of charged massive or massless fermions can be described by the two-dimensional Dirac Hamiltonians with an usual (-a/r) Coulomb potential. These Hamiltonians are singular and require the additional definition in order for them to be treated as self-adjoint quantum-mechanical operators. We construct the self-adjoint two-dimensional Dirac Hamiltonians with a Coulomb potential and determine the quantum-mechanical states for such Hamiltonians in the corresponding Hilbert spaces of square-integrable functions. We determine the scattering amplitude in which the self-adjoint extension parameter is incorporated and then obtain equations implicitly defining possible discrete energy spectra of the self-adjoint Dirac Hamiltonians with a Coulomb potential. It is shown that this quantum system becomes unstable in the presence of a supercritical Coulomb potential which manifests in the appearance of quasi-stationary states in the lower (negative) energy continuum. The energy spectrum of those states is quasi-discrete, consists of broadened levels with widths related to the inverse lifetimes of the quasi-stationary states as well as the probability of creation of charged fermion pair by a supercritical Coulomb field. Explicit analytical expressions for the creation probabilities of charged (massive or massless) fermion pair are obtained in a supercritical Coulomb field.
Coulombic and neutral trapping centers in silicon dioxide
Buchanan, D. A.; Fischetti, M. V.; Dimaria, D. J.
1991-01-01
Metal-oxide-semiconductor structures incorporating thermally grown silicon dioxide films were implanted with arsenic ions and then annealed at high temperatures. The subsequent trapping sites produced are amphoteric. Coulombic-attractive traps (for electrons) were produced with the avalanche injection of holes from the silicon substrate and the subsequent capture of some of these holes on the arsenic-related sites. During internal photoemission of electrons from a thin aluminum gate, the voltage shifts due to hole annihilation by electrons were recorded and the effective capture cross section was determined. This capture cross section was found to vary from ~10-12 to 3×10-15 cm2 for average electric fields ranging from 2×105 to 3×106 V/cm. An average field threshold (~1.2×106 V/cm) was found, below which the capture-cross-section-average-field dependence follows a power law with an exponent of approximately -1.5. Above the average field threshold, the power-law exponent was found to be approximately -3.0. Also, when the amphoteric arsenic-related sites are empty, they can form neutral trapping sites for electrons. For these trapping centers, it is found that the neutral capture cross section is relatively independent of the average electric field. For average fields ranging from 5×105 to 6×106 V/cm, the neutral cross section is found to be approximately constant at (1-2)×10-15 cm2. For the Coulombic electron traps, classical and quantum-mechanical Monte Carlo simulations agree qualitatively with the experimental results. These simulations suggest that the heating of the electron-energy distribution and tunnel detrapping are the primary cause of the decrease in the effective capture cross section in the high-field regime. For the neutral traps in the low-field regime, the classical Monte Carlo simulation also agrees with the experimental results. However, for fields above the electron-heating threshold, the simulation predicts an increase in the capture cross
Polarons as stable solitary wave solutions to the Dirac-Coulomb system
Comech, Andrew; Zubkov, Mikhail
2013-11-01
We consider solitary wave solutions to the Dirac-Coulomb system both from physical and mathematical points of view. Fermions interacting with gravity in the Newtonian limit are described by the model of Dirac fermions with the Coulomb attraction. This model also appears in certain condensed matter systems with emergent Dirac fermions interacting via optical phonons. In this model, the classical soliton solutions of equations of motion describe the physical objects that may be called polarons, in analogy to the solutions of the Choquard equation. We develop analytical methods for the Dirac-Coulomb system, showing that the no-node gap solitons for sufficiently small values of charge are linearly (spectrally) stable.
Impact of electron-electron Coulomb interaction on the high harmonic generation process in graphene
Avetissian, H. K.; Mkrtchian, G. F.
2018-03-01
Generation of high harmonics in a monolayer graphene initiated by a strong coherent radiation field, taking into account electron-electron Coulomb interaction, is investigated. A microscopic theory describing the nonlinear optical response of graphene is developed. The Coulomb interaction of electrons is treated in the scope of dynamic Hartree-Fock approximation. The closed set of integrodifferential equations for the single-particle density matrix of a graphene quantum structure is solved numerically. The obtained solutions show the significance of many-body Coulomb interaction on the high harmonic generation process in graphene.
International Nuclear Information System (INIS)
Zhang Wenwen; Hou Xun; Wu Zhaoxin; Liang Shixiong; Jiao Bo; Zhang Xinwen; Wang Dawei; Chen Zhijian; Gong Qihuang
2011-01-01
The luminance decays of organic light-emitting diodes (OLEDs) are investigated with initial luminance of 1000 to 20 000 cd m -2 through a scalable Coulombic degradation and a stretched exponential decay. We found that the estimated lifetime by scalable Coulombic degradation deviates from the experimental results when the OLEDs work with high initial luminance. By measuring the temperature of the device during degradation, we found that the higher device temperatures will lead to instabilities of organic materials in devices, which is expected to result in the difference between the experimental results and estimation using the scalable Coulombic degradation.
Coulomb scatter of diamagnetic dust particles in a cusp magnetic trap under microgravity conditions
Energy Technology Data Exchange (ETDEWEB)
Myasnikov, M. I., E-mail: miasnikovmi@mail.ru; D’yachkov, L. G.; Petrov, O. F.; Vasiliev, M. M., E-mail: mixxy@mail.ru; Fortov, V. E. [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation); Savin, S. F.; Serova, E. O. [Korolev Rocket and Space Corporation Energia, ul. Lenina 4A (Russian Federation)
2017-02-15
The effect of a dc electric field on strongly nonideal Coulomb systems consisting of a large number (~10{sup 4}) of charged diamagnetic dust particles in a cusp magnetic trap are carried out aboard the Russian segment of the International Space Station (ISS) within the Coulomb Crystal experiment. Graphite particles of 100–400 μm in size are used in the experiments. Coulomb scatter of a dust cluster and the formation of threadlike chains of dust particles are observed experimentally. The processes observed are simulated by the molecular dynamics (MD) method.
Coulomb blockade and transfer of electrons one by one
International Nuclear Information System (INIS)
Pothier, Hugues
1991-01-01
Zero point fluctuations of the charge on the capacitance of a tunnel junction connected to a bias circuit are in almost all experimental situations larger than the electron charge. As a consequence, the effects of charge granularity are hidden, but in circuits with 'islands', which are electrodes connected to the rest of the circuit only through tunnel junctions and capacitors. The island charge being quantized, its fluctuations are blocked. If the island capacitance is sufficiently small, no electron can enter the island because of the increase of electrostatic energy that would occur. We have observed this effect, called 'Coulomb blockade', in the 'single electron box', where an island is formed between a tunnel junction and a capacitor. A bias voltage source coupled to the island through the capacitor allows to control the number of electrons. We have designed and operated two devices with nano-scale tunnel junctions based on this principle, the 'turnstile' and the 'pump', through which the current is controlled electron by electron. In our experiments, the precision of the transfer is of the order of one percent. It should be a million time better in versions of these devices with more junctions. One could then use them for a new measurement of the fine structure constant alpha. (author) [fr
Coulomb problem for a Z>Z_cr nucleus
Kuleshov, V. M.; Mur, V. D.; Narozhny, N. B.; Fedotov, A. M.; Lozovik, Yu E.; Popov, V. S.
2015-08-01
A closed-form equation is derived for the critical nucleus charge Z=Z_cr at which a discrete level with the Dirac quantum number touches the lower continuum of the Dirac equation solutions. For the Coulomb potential cut off rectangularly at the short distance r0 = R{\\hbar}/(mc), R \\ll {1}, the critical nucleus charge values are obtained for several values of κ and R. It is shown that the partial scattering matrix of elastic positron-nucleus scattering, Sκ = \\exp(2iδκ(\\varepsilon_p)), is also unitary for Z>Z_cr. For this range, the scattering phase δ κ (\\varepsilon _p) is calculated as a function of the positron energy E_p = \\varepsilonp mc2, as are the positions and widths of quasidiscrete levels corresponding to the scattering matrix poles. The implication is that the single-particle approximation for the Dirac equation is valid not only for Z but also for Z>Z_cr and that there is no spontaneous creation of e^+e^- pairs from the vacuum.
Analytic quantum-interference conditions in Coulomb corrected photoelectron holography
Maxwell, A. S.; Al-Jawahiry, A.; Lai, X. Y.; Figueira de Morisson Faria, C.
2018-02-01
We provide approximate analytic expressions for above-threshold ionization (ATI) transition probabilities and photoelectron angular distributions. These analytic expressions are more general than those existing in the literature and include the residual binding potential in the electron continuum propagation. They successfully reproduce the ATI side lobes and specific holographic structures such as the near-threshold fan-shaped pattern and the spider-like structure that extends up to relatively high photoelectron energies. We compare such expressions with the Coulomb quantum orbit strong-field approximation (CQSFA) and the full solution of the time-dependent Schrödinger equation for different driving-field frequencies and intensities, and provide an in-depth analysis of the physical mechanisms behind specific holographic structures. Our results shed additional light on what aspects of the CQSFA must be prioritized in order to obtain the key holographic features, and highlight the importance of forward scattered trajectories. Furthermore, we find that the holographic patterns change considerably for different field parameters, even if the Keldysh parameter is kept roughly the same.
Deuteron Coulomb Excitation in Peripheral Collisions with a Heavy Ion
Du, Weijie; Yin, Peng; Li, Yang; Chen, Guangyao; Zuo, Wei; Zhao, Xingbo; Vary, James P.
2017-09-01
We develop an ab initio time-dependent Basis Function (tBF) method to solve non-perturbative and time-dependent problems in non-relativistic quantum mechanics. As a test problem, we apply this method to the Coulomb excitation of a deuteron by an impinging heavy ion. We employ wave functions for the bound and excited states of the deuterium system based on a realistic nucleon-nucleon interaction and study the evolution of the transition probability, the r.m.s. radius and the r.m.s. momentum of the system during the scattering process. The dependencies of these quantities on the external field strength and the bombarding energy are also analyzed and compared to corresponding results obtained from first-order perturbation theory. The time evolution of both the charge and the momentum distributions is shown. This work was supported in part by the U. S. Department of Energy (DOE) under Grants No. DESC0008485 (SciDAC/NUCLEI) and DE-FG02-87ER40371. W. Zuo and P. Yin are supported by the National Natural Science Foundation of China (11435014).
Shape determination in Coulomb excitation of $^{72}$Kr
Reiter, P; Kruecken, R; Paul, E S; Wadsworth, R; Heenen, P
Nuclei with oblate shapes at low spins are very special in nature because of their rarity. Both theoretical and experimental shape co-existence studies in the mass 70 region for near proton drip-line nuclei suggest $^{72}$Kr to be the unique case with oblate low-lying and prolate high-lying levels. However, there is no direct experimental evidence in the literature to date for the oblate nature predicted for the first 2$^+$ state in $^{72}$Kr. We propose to determine the sign of the spectroscopic quadrupole moment of this state via the re-orientation effect in a low-energy Coulomb excitation measurement. In the inelastic excitation of the 2$^+$ state in $^{72}$Kr beam of 3.1 MeV/u with an intensity of 800 pps at REX-ISOLDE impinging on $^{104}$Pd target, the re-orientation effect plays a significant role. The cross section measurement for the 2$^+$ state should thus allow the model-independent determination of the sign of the quadrupole moment unambiguously and will shed light on the co-existing prolate and o...
Coulomb excitation of $^{110}$Sn using REX-ISOLDE
Ekström, A; Hurst, A; Fahlander, C; Banu, A; Butler, P; Eberth, J; Górska, M; Habs, D; Huyse, M; Kester, O; Niedermayer, O; Nilsson, T; Pantea, M; Scheit, H; Schwalm, D; Sletten, G; Ushasi, D P; Van Duppen, P; Warr, N; Weisshaar, D
2006-01-01
In this paper, we report the preliminary result from the first Coulomb excitation experiment at REX-ISOLDE (Habs et al 1998 Nucl. Instrum. Methods B 139 128) using neutron-deficient Sn-beams. The motivation of the experiment is to deduce the reduced transition probability, B(E2 ; 2$^+\\rightarrow$ 0$^+$) , for the sequence of neutron deficient, unstable, even-even Sn-isotopes from using a radioactive beam opens up a new path to study the lifetime of the first excited 2$^+$ state in these isotopes. The de-excitation path following fusion-evaporation reactions will for the even-even Sn isotopes pass via an isomeric 6$^+$ state, located at higher energy, which thus hampers measurements of the lifetime of the first excited state using, e.g., recoil-distance methods. For this reason the reduced transition probability of the first excited 2$^+$ state has remained unknown in this chain of isotopes although the B(E2) value of the stable isotope $^{112}$Sn was measured approximately 30 years ago (see, e.g., Stelson et...
Coulomb nuclear interference with deuterons in even palladium isotopes
Energy Technology Data Exchange (ETDEWEB)
Rodrigues, M.R.D.; Rodrigues, C.L.; Borello-Lewin, T.; Horodynski-Matsushigue, L.B.; Duarte, J. L.M. [Sao Paulo Univ., SP (Brazil); Ukita, G.M. [Universidade de Santo Amaro, SP (Brazil). Faculdade de Psicologia
2004-09-15
Angular distributions for the inelastic scattering of 13.0 MeV deuterons on {sup 104,106,108,110}Pd were measured with the Sao Paulo Pelletron-Enge-Spectrograph facility in the range of 12{sup 0} {<=}{theta}{sub lab} {<=}64{sup 0}. A Coulomb-Nuclear Interference analysis, employing the Distorted Wave Born Approximation with the Deformed Optical Model as transition potential, under well established global optical parameters, was applied to the first quadrupolar excitations. The values of C = {delta}{sub LC}/{delta}{sub LN}, the ratio of charge to isoscalar deformation lengths, and of ({delta}{sub LN}){sup 2} were extracted through the comparison of experimental and predicted cross section angular distributions. The ratios of reduced charge to isoscalar transition probabilities, B(EL) to B(ISL) respectively, are related to the square of the parameter C and were thus obtained with the advantage of scale uncertainties cancellation. For {sup 104}Pd, and preliminary for {sup 108}Pd, the respective values of C = 1.18(3) and C = 1.13(4) reveal an enhanced contribution of the protons relative to the neutrons to the excitation, while a smaller effect is found for {sup 106}Pd, C = 1.06(3) and for {sup 110}Pd, C 1.07(3), in comparison with the value C 1.00 expected for homogenous collective excitations. (author)
Coulomb nuclear interference with deuterons in even palladium isotopes
International Nuclear Information System (INIS)
Rodrigues, M.R.D.; Rodrigues, C.L.; Borello-Lewin, T.; Horodynski-Matsushigue, L.B.; Duarte, J. L.M.; Ukita, G.M.
2004-01-01
Angular distributions for the inelastic scattering of 13.0 MeV deuterons on 104,106,108,110 Pd were measured with the Sao Paulo Pelletron-Enge-Spectrograph facility in the range of 12 0 ≤θ lab ≤64 0 . A Coulomb-Nuclear Interference analysis, employing the Distorted Wave Born Approximation with the Deformed Optical Model as transition potential, under well established global optical parameters, was applied to the first quadrupolar excitations. The values of C = δ LC /δ LN , the ratio of charge to isoscalar deformation lengths, and of (δ LN ) 2 were extracted through the comparison of experimental and predicted cross section angular distributions. The ratios of reduced charge to isoscalar transition probabilities, B(EL) to B(ISL) respectively, are related to the square of the parameter C and were thus obtained with the advantage of scale uncertainties cancellation. For 104 Pd, and preliminary for 108 Pd, the respective values of C = 1.18(3) and C = 1.13(4) reveal an enhanced contribution of the protons relative to the neutrons to the excitation, while a smaller effect is found for 106 Pd, C = 1.06(3) and for 110 Pd, C 1.07(3), in comparison with the value C 1.00 expected for homogenous collective excitations. (author)
Ghorai, Sankar; Chaudhury, Pinaki
2017-12-28
We have used a replica exchange Monte-Carlo procedure, popularly known as Parallel Tempering, to study the problem of Coulomb explosion in homogeneous Ar and Xe dicationic clusters as well as mixed Ar-Xe dicationic clusters of varying sizes with different degrees of relative composition. All the clusters studied have two units of positive charges. The simulations reveal that in all the cases there is a cutoff size below which the clusters fragment. It is seen that for the case of pure Ar, the value is around 95 while that for Xe it is 55. For the mixed clusters with increasing Xe content, the cutoff limit for suppression of Coulomb explosion gradually decreases from 95 for a pure Ar to 55 for a pure Xe cluster. The hallmark of this study is this smooth progression. All the clusters are simulated using the reliable potential energy surface developed by Gay and Berne (Gay and Berne, Phys. Rev. Lett. 1982, 49, 194). For the hetero clusters, we have also discussed two different ways of charge distribution, that is one in which both positive charges are on two Xe atoms and the other where the two charges are at a Xe atom and at an Ar atom. The fragmentation patterns observed by us are such that single ionic ejections are the favored dissociating pattern. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.
The Alaska earthquake, March 27, 1964: lessons and conclusions
Eckel, Edwin B.
1970-01-01
One of the greatest earthquakes of all time struck south-central Alaska on March 27, 1964. Strong motion lasted longer than for most recorded earthquakes, and more land surface was dislocated, vertically and horizontally, than by any known previous temblor. Never before were so many effects on earth processes and on the works of man available for study by scientists and engineers over so great an area. The seismic vibrations, which directly or indirectly caused most of the damage, were but surface manifestations of a great geologic event-the dislocation of a huge segment of the crust along a deeply buried fault whose nature and even exact location are still subjects for speculation. Not only was the land surface tilted by the great tectonic event beneath it, with resultant seismic sea waves that traversed the entire Pacific, but an enormous mass of land and sea floor moved several tens of feet horizontally toward the Gulf of Alaska. Downslope mass movements of rock, earth, and snow were initiated. Subaqueous slides along lake shores and seacoasts, near-horizontal movements of mobilized soil (“landspreading”), and giant translatory slides in sensitive clay did the most damage and provided the most new knowledge as to the origin, mechanics, and possible means of control or avoidance of such movements. The slopes of most of the deltas that slid in 1964, and that produced destructive local waves, are still as steep or steeper than they were before the earthquake and hence would be unstable or metastable in the event of another great earthquake. Rockslide avalanches provided new evidence that such masses may travel on cushions of compressed air, but a widely held theory that glaciers surge after an earthquake has not been substantiated. Innumerable ground fissures, many of them marked by copious emissions of water, caused much damage in towns and along transportation routes. Vibration also consolidated loose granular materials. In some coastal areas, local
SUSY shape-invariant Hamiltonians for the generalized dirac-coulomb problem
International Nuclear Information System (INIS)
Rodrigues, R. de Lima; Vaidya, Arvind Narayan
2007-02-01
A spin 1/2 relativistic particle described by a general potential in terms of the sum of the Coulomb potential with a Lorentz scalar potential is investigated via supersymmetry in quantum mechanics. (author)
Generalized ladder operators for the Dirac-Coulomb problem via SUSY QM
International Nuclear Information System (INIS)
Rodrigues, R. de Lima; Universidade Federal de Campina Grande, PB
2003-12-01
The supersymmetry in quantum mechanics and shape invariance condition are applied as an algebraic method to solving the Dirac-Coulomb problem. The ground state and the excited states are investigated via new generalized ladder operators. (author)
Energy Technology Data Exchange (ETDEWEB)
García-Ravelo, J., E-mail: g.ravelo@hotmail.com [Departamento de Física, Escuela Superior de Física y Matemáticas, Instituto Politécnico Nacional, Edificio 9, Unidad Profesional Adolfo López Mateos, México D.F., 07738 (Mexico); Menéndez, A.; García-Martínez, J. [Departamento de Física, Escuela Superior de Física y Matemáticas, Instituto Politécnico Nacional, Edificio 9, Unidad Profesional Adolfo López Mateos, México D.F., 07738 (Mexico); Schulze-Halberg, A. [Department of Mathematics and Actuarial Science and Department of Physics, Indiana University Northwest, 3400 Broadway, Gary, IN 46408 (United States)
2014-06-13
We show that the effective Kratzer and Coulomb potentials can be obtained by taking particular limits of a multiparameter exponential potential that was studied recently. Moreover, we demonstrate that the bound state solutions of the exponential potential reduce correctly to their well-known counterparts associated with the Kratzer and Coulomb potentials. As a byproduct, we obtain a new limit relation for the hypergeometric function. - Highlights: • Kratzer and Coulomb potentials are limit cases of an exponential-type potential. • From exact s-waves, approximate solutions for l-waves are obtained. • l-waves of the potential tend to the solutions of the Kratzer and Coulomb potentials. • A non-evident identity between hypergeometric functions is demonstrated.
International Nuclear Information System (INIS)
García-Ravelo, J.; Menéndez, A.; García-Martínez, J.; Schulze-Halberg, A.
2014-01-01
We show that the effective Kratzer and Coulomb potentials can be obtained by taking particular limits of a multiparameter exponential potential that was studied recently. Moreover, we demonstrate that the bound state solutions of the exponential potential reduce correctly to their well-known counterparts associated with the Kratzer and Coulomb potentials. As a byproduct, we obtain a new limit relation for the hypergeometric function. - Highlights: • Kratzer and Coulomb potentials are limit cases of an exponential-type potential. • From exact s-waves, approximate solutions for l-waves are obtained. • l-waves of the potential tend to the solutions of the Kratzer and Coulomb potentials. • A non-evident identity between hypergeometric functions is demonstrated
A Hamilton-like vector for the special-relativistic Coulomb problem
International Nuclear Information System (INIS)
Munoz, Gerardo; Pavic, Ivana
2006-01-01
A relativistic point charge moving in a Coulomb potential does not admit a conserved Hamilton vector. Despite this fact, a Hamilton-like vector may be developed that proves useful in the derivation and analysis of the particle's orbit
Gribov horizon and the one-loop color-Coulomb potential
DEFF Research Database (Denmark)
Golterman, Maarten; Greensite, Jeffrey Paul; Peris, Santiago
2012-01-01
We recalculate the color-Coulomb potential to one-loop order, under the assumption that the effect of the Gribov horizon is to make (i) the transverse gluon propagator less singular and (ii) the color-Coulomb potential more singular than their perturbative behavior in the low-momentum limit....... As a first guess, the effect of the Gribov horizon is mimicked by introducing a transverse momentum-dependent gluon mass term, leading to a propagator of the Gribov form, with the prescription that the mass parameter should be adjusted to the unique value where the infrared behavior of the Coulomb potential...... is enhanced. We find that this procedure leads to a Coulomb potential rising asymptotically as a linear term modified by a logarithm....
Shape coexistence in neutron-rich Sr isotopes : Coulomb excitation of 98Sr
Clément, E; Görgen, A.; Korten, W.; Walle J. van de, [No Value
2010-01-01
In this addendum we ask for beam time to perform Coulomb excitation of 98Sr in order to complete our program on the study of shape coexistence and evolution of collectivity in neutron rich strontium isotopes at N=60.
Scattering of the Halo Nucleus ^{11}Be on ^{197}Au at Energies around the Coulomb Barrier.
Pesudo, V; Borge, M J G; Moro, A M; Lay, J A; Nácher, E; Gómez-Camacho, J; Tengblad, O; Acosta, L; Alcorta, M; Alvarez, M A G; Andreoiu, C; Bender, P C; Braid, R; Cubero, M; Di Pietro, A; Fernández-García, J P; Figuera, P; Fisichella, M; Fulton, B R; Garnsworthy, A B; Hackman, G; Hager, U; Kirsebom, O S; Kuhn, K; Lattuada, M; Marquínez-Durán, G; Martel, I; Miller, D; Moukaddam, M; O'Malley, P D; Perea, A; Rajabali, M M; Sánchez-Benítez, A M; Sarazin, F; Scuderi, V; Svensson, C E; Unsworth, C; Wang, Z M
2017-04-14
Angular distributions of the elastic, inelastic, and breakup cross sections of the halo nucleus ^{11}Be on ^{197}Au were measured at energies below (E_{lab}=31.9 MeV) and around (39.6 MeV) the Coulomb barrier. These three channels were unambiguously separated for the first time for reactions of ^{11}Be on a high-Z target at low energies. The experiment was performed at TRIUMF (Vancouver, Canada). The differential cross sections were compared with three different calculations: semiclassical, inert-core continuum-coupled-channels and continuum-coupled-channels ones with including core deformation. These results show conclusively that the elastic and inelastic differential cross sections can only be accounted for if core-excited admixtures are taken into account. The cross sections for these channels strongly depend on the B(E1) distribution in ^{11}Be, and the reaction mechanism is sensitive to the entanglement of core and halo degrees of freedom in ^{11}Be.
Coulomb excitation of the odd-odd isotopes $^{106, 108}$In
Ekstrom, A; Blazhev, A; Van de Walle, J; Weisshaar, D; Zielinska, M; Tveten, G M; Marsh, B A; Siem, S; Gorska, M; Engeland, T; Hurst, A M; Cederkall, J; Finke, F; Iwanicki, J; Hjorth-Jensen, M; Davinson, T; Eberth, J; Sletten, G; Mierzejewski, J; Reiter, P; Warr, N; Butler, P A; Fahlander, C; Stefanescu, I; Koester, U; Ivanov, O; Wenander, F; Voulot, D
2010-01-01
The low-lying states in the odd-odd and unstable isotopes In-106,In-108 have been Coulomb excited from the ground state and the first excited isomeric state at the REX-ISOLDE facility at CERN. With the additional data provided here the pi g(9/2)(-1) circle times nu d(5/2) and pi g(9/2)(-1) circle times nu g7/2 multiplets have been re-analyzed and are modified compared to previous results. The observed gamma-ray de-excitation patterns were interpreted within a shell model calculation based on a realistic effective interaction. The agreement between theory and experiment is satisfactory and the calculations reproduce the observed differences in the excitation pattern of the two isotopes. The calculations exclude a 6(+) ground state in In-106. This is in agreement with the conclusions drawn using other techniques. Furthermore, based on the experimental results, it is also concluded that the ordering of the isomeric and ground state in In-108 is inverted compared to the shell model prediction. Limits on B(E2) val...
Coulomb excitation of the odd-odd isotopes {sup 106,108}In
Energy Technology Data Exchange (ETDEWEB)
Ekstroem, A.; Fahlander, C. [University of Lund, Physics Department, Box 118, Lund (Sweden); Cederkaell, J. [University of Lund, Physics Department, Box 118, Lund (Sweden); CERN, PH Department, Geneva 23 (Switzerland); Hjorth-Jensen, M.; Engeland, T. [University of Oslo, Physics Department and Center of Mathematics for Applications, Oslo (Norway); Blazhev, A.; Eberth, J.; Finke, F.; Reiter, P.; Warr, N.; Weisshaar, D. [University of Cologne, Institute of Nuclear Physics, Cologne (Germany); Butler, P.A.; Hurst, A.M. [University of Liverpool, Oliver Lodge Laboratory, Liverpool (United Kingdom); Davinson, T. [University of Edinburgh, Department of Physics and Astronomy, Edinburgh (United Kingdom); Goergen, A. [Service de Physique Nucleaire, CEA Saclay, Gif-sur-Yvette (France); Gorska, M. [Gesellschaft fuer Schwerionenforschung, Darmstadt (Germany); Ivanov, O.; Stefanescu, I. [Instituut voor Kern- en Stralingsfysica, K.U. Leuven (Belgium); Iwanicki, J. [University of Warsaw, Heavy Ion Laboratory, Warsaw (Poland); Koester, U. [CERN, PH Department, Geneva 23 (Switzerland); Institut Laue Langevin, Grenoble (France); Marsh, B.A. [University of Manchester, Department of Physics, Manchester (United Kingdom); CERN, AB Department, Geneva 23 (Switzerland); Mierzejewski, J. [University of Warsaw, Heavy Ion Laboratory, Warsaw (Poland); University of Warsaw, Institute of Experimental Physics, Warsaw (Poland); Siem, S. [University of Oslo, Department of Physics, Oslo (Norway); Sletten, G. [University of Copenhagen, Physics Department, Copenhagen (Denmark); Tveten, G.M. [CERN, PH Department, Geneva 23 (Switzerland); University of Oslo, Department of Physics, Oslo (Norway); Van de Walle, J. [CERN, PH Department, Geneva 23 (Switzerland); Instituut voor Kern- en Stralingsfysica, K.U. Leuven (Belgium); Voulot, D.; Wenander, F. [CERN, AB Department, Geneva 23 (Switzerland)
2010-06-15
The low-lying states in the odd-odd and unstable isotopes {sup 106,108}In have been Coulomb excited from the ground state and the first excited isomeric state at the REX-ISOLDE facility at CERN. With the additional data provided here the {pi}g{sub 9/2}{sup -1} x {nu}d{sub 5/2} and {pi}g{sub 9/2}{sup -1} x {nu} g{sub 7/2} multiplets have been re-analyzed and are modified compared to previous results. The observed {gamma} -ray de-excitation patterns were interpreted within a shell model calculation based on a realistic effective interaction. The agreement between theory and experiment is satisfactory and the calculations reproduce the observed differences in the excitation pattern of the two isotopes. The calculations exclude a 6{sup +} ground state in {sup 106}In. This is in agreement with the conclusions drawn using other techniques. Furthermore, based on the experimental results, it is also concluded that the ordering of the isomeric and ground state in {sup 108}In is inverted compared to the shell model prediction. Limits on B(E2) values have been extracted where possible. A previously unknown low-lying state at 367keV in {sup 106}In is also reported. (orig.)
Fusion of 48Ti+58Fe and 58Ni+54Fe below the Coulomb barrier
Stefanini, A. M.; Montagnoli, G.; Corradi, L.; Courtin, S.; Bourgin, D.; Fioretto, E.; Goasduff, A.; Grebosz, J.; Haas, F.; Mazzocco, M.; Mijatović, T.; Montanari, D.; Pagliaroli, M.; Parascandolo, C.; Scarlassara, F.; Strano, E.; Szilner, S.; Toniolo, N.; Torresi, D.
2015-12-01
Background: No data on the fusion excitation function of 48Ti+58Fe in the energy region near the Coulomb barrier existed prior to the present work, while fusion of 58Ni+54Fe was investigated in detail some years ago, down to very low energies, and clear evidence of fusion hindrance was noticed at relatively high cross sections. 48Ti and 58Fe are soft and have a low-lying quadrupole excitation lying at ≈800 -900 keV only. Instead, 58Ni and 54Fe have a closed shell (protons and neutrons, respectively) and are rather rigid. Purpose: We aim to investigate (1) the possible influence of the different structures of the involved nuclei on the fusion excitation functions far below the barrier and, in particular, (2) whether hindrance is observed in 48Ti+58Fe , and to compare the results with current coupled-channels models. Methods: 48Ti beams from the XTU Tandem accelerator of INFN-Laboratori Nazionali di Legnaro were used. The experimental setup was based on an electrostatic beam separator, and fusion-evaporation residues (ERs) were detected at very forward angles. Angular distributions of ERs were measured. Results: Fusion cross sections of 48Ti+58Fe have been obtained in a range of nearly six orders of magnitude around the Coulomb barrier, down to σ ≃2 μ b . The sub-barrier cross sections of 48Ti+58Fe are much larger than those of 58Ni+54Fe . Significant differences are also observed in the logarithmic derivatives and astrophysical S factors. No evidence of hindrance is observed, because coupled-channels calculations using a standard Woods-Saxon potential are able to reproduce the data in the whole measured energy range. Analogous calculations for 58Ni+54Fe predict clearly too large cross sections at low energies. The two fusion barrier distributions are wide and display a complex structure that is only qualitatively fit by calculations. Conclusions: It is pointed out that all these different trends originate from the dissimilar low-energy nuclear structures of
Numerical Investigations of the Three-Dimensional Proton-Proton Screened Coulomb t-Matrix
International Nuclear Information System (INIS)
Skibinski, R.; Golak, J.; Witala, H.
2010-01-01
We demonstrate behaviour of the momentum space screened Coulomb t-matrix, obtained by a numerical solution of the three-dimensional Lippmann- Schwinger equation. Examples are given for different types of screening. They prove that it is possible to obtain numerically a reliable three dimensional screened Coulomb t-matrix, what is important in view of its application in few-body calculations. (authors)
Dependence of conductivity on thickness within the variable-range hopping regime for Coulomb glasses
Directory of Open Access Journals (Sweden)
M. Caravaca
Full Text Available In this paper, we provide some computational evidence concerning the dependence of conductivity on the system thickness for Coulomb glasses. We also verify the EfrosâShklovskii law and deal with the calculation of its characteristic parameter as a function of the thickness. Our results strengthen the link between theoretical and experimental fields. Keywords: Coulomb glass, Conductivity, Density of states, EfrosâShklovskii law
Zeeman splitting spin filter in a single quantum dot electron transport with Coulomb blockade effect
Lai, Wenxi
2014-01-01
Electron spin filter induced by Zeeman splitting in a few-electron quantum dot coupled to two normal electrodes is studied considering Coulomb blockade effect. Based on the Anderson model and Liouville-von Neumann equation, equation of motion of the system is derived and analytical solutions are achieved. Transport windows for perfectly polarized current, partially polarized current and non-polarized current induced by the Zeeman splitting energy and Coulomb blockade potential are exploited. ...
Coulomb dissociation of {sup 8}B at 254 A MeV
Energy Technology Data Exchange (ETDEWEB)
Suemmerer, K.; Boue, F.; Baumann, T.; Geissel, H.; Hellstroem, M.; Koczon, P.; Schwab, E.; Schwab, W.; Senger, P.; Surowiecz, A. [Gesellschaft fuer Schwerionenforschung (GSI), Darmstadt (Germany); Iwasa, N.; Ozawa, A. [Gesellschaft fuer Schwerionenforschung (GSI), Darmstadt (Germany)]|[RIKEN Institute of Physical and Chemical Research, Saitama (Japan); Surowka, G. [Gesellschaft fuer Schwerionenforschung (GSI), Darmstadt (Germany)]|[Jagiellonian Univ., Krakow (Poland). Inst. of Physics; Blank, B.; Czajkowski, S.; Marchand, C.; Pravikoff, M.S. [Centre d`Etudes Nucleaires de Bordeaux-Gradignan, 33 (France); Foerster, A.; Lauer, F.; Oeschler, H.; Speer, J.; Sturm, C.; Uhlig, F.; Wagner, A. [Technische Univ. Darmstadt (Germany); Gai, M. [Connecticut Univ., Storrs, CT (United States). Dept. of Physics; Grosse, E. [Inst. fuer Kern- und Hadronenphysik, Forschungszentrum Rossendorf, Dresden (Germany); Kohlmeyer, B. [Philipps Univ., Marburg (Germany). Fachbereich Physik; Kulessa, R.; Walus, W. [Jagiellonian Univ., Krakow (Poland). Inst. of Physics; Motobayashi, T. [Rikkyo Univ., Tokyo (Japan). Dept. of Physics; Teranishi, T. [RIKEN Institute of Physical and Chemical Research, Saitama (Japan)
1998-06-01
As an alternative method for determining the astrophysical S-factor for the {sup 7}Be(p,{gamma}){sup 8}B reaction we have measured the Coulomb dissociation of {sup 8}B at 254 A MeV. From our preliminary results, we obtain good agreement with both the accepted direct-reaction measurements and the low-energy Coulomb dissociation study of Iwasa et al. performed at about 50 A MeV. (orig.)
Quantum effects on the coulomb logarithm for energetic ions during the initial thermalization phase
Deng Bai Quan; Deng Mei Gen; Peng Li Lin
2002-01-01
The authors have discussed the quantum mechanical effects for the energetic charged particles produced in D-He sup 3 fusion reactions. Authors' results show that it is better to use the proper Coulomb logarithm at the high-energy end in describing the thermalization process, because the quantum mechanical effects on the Coulomb logarithm are not negligible, based on an assumption of binary collision
Alpha particles-and 3He inelastic scattering by 124Sn in the coulomb barrier region
International Nuclear Information System (INIS)
Appoloni, C.R.
1976-01-01
Angular distributions for inelastic scattering of α and 3 He particles in 124 Sn at the incident energies around Coulomb barrier were measured using the 8UD Pelletron Tandem Accelerator of The University of Sao Paulo. The results were analysed by DWBA with a collective form factor including the effects due to the interference between coulomb and nuclear excitations with the code PATIWEN (Ba75). The nuclear deformation parameters for the one phonon levels (2 + and 3 - ) have been obtained. (Author) [pt
Elastic scattering of intermediate energy kaons from nuclei and its Coulomb effects
Energy Technology Data Exchange (ETDEWEB)
Zhang Zhenqiu; Kong Lingjiang; Liu Xianhui
1986-04-01
In the frame of the eikonal multiple scattering theory, using the basic parameters which are given by the different authors, the elastic scattering of the intermediate energy kaon mesons on /sup 12/C and /sup 40/Ca is studied. The Coulomb effect is calculated too. The results are in agreement with the experimental data. The Coulomb effect not only enhances the small angle differential cross section, but also fills up the dip of the differential cross section.
A uniform semi-classical approach to the Coulomb fission problem
International Nuclear Information System (INIS)
Levit, S.; Smilansky, U.
1978-01-01
A semi-classical theory based on the path integral formalism is applied to the description of Coulomb fission. Complex classical trajectories are used to compute the classically forbidden transitions from the target's ground state to fission. In a simple model the energy spectrum and angular distributions of the fragments are calculated for the Coulomb fission in the Xe + U collision. Theoretical predictions are made which may be checked experimentally. (author)
Breakdown of the Coulomb friction law in TiC/a-C:H nanocomposite coatings
International Nuclear Information System (INIS)
Pei, Y. T.; Huizenga, P.; Galvan, D.; Hosson, J. Th. M. de
2006-01-01
Advanced TiC/a-C:H nanocomposite coatings have been produced via reactive deposition in a closed-field unbalanced magnetron sputtering system (Hauzer HTC-1000 or HTC 1200). In this paper, we report on the tribological behavior of TiC/a-C:H nanocomposite coatings in which ultralow friction is tailored with superior wear resistance, two properties often difficult to achieve simultaneously. Tribotests have been performed at room temperature with a ball-on-disk configuration. In situ monitoring of the wear depth of the coated disk together with the wear height of the ball counterpart at nanometer scale reveals that the self-lubricating effects are induced by the formation of transfer films on the surface of the ball counterpart. A remarkable finding is a breakdown of the Coulomb friction law in the TiC/a-C:H nanocomposite coatings. In addition, the coefficient of friction of TiC/a-C:H nanocomposite coatings decreases with decreasing relative humidity. A superior wear resistance of the coated disk at a level of 10 -17 m 3 /N m (per lap) has been achieved under the condition of superlow friction and high toughness, both of which require fine TiC nanoparticles (e.g., 2 nm) and a wide matrix separation that must be comparable to the dimensions of the nanoparticles
Number of objectives and conclusions in dissertations and thesis
Directory of Open Access Journals (Sweden)
Liebano Richard Eloin
2005-01-01
Full Text Available PURPOSE: To analyze the number of objectives and conclusions presented in dissertations and thesis defended at Federal University of São Paulo - Paulista School of Medicine (UNIFESP - EPM. METHODS: It was realized a search in the master degree dissertations and doctor degree thesis defended at Federal University of São Paulo - Paulista School of Medicine in the years 2002 and 2003 that were found available in the central library of this university. RESULTS: From 723 master dissertations analyzed, 62 (8,57% presented only one objective and one conclusion, 134 (18,53% presented one objective and more than one conclusion and 527 (72,89% had more than one objective and more than one conclusion. From 502 doctor thesis analyzed, 23 (4,58% presented only one objective and one conclusion, 123 (24,50% presented one objective and more than one conclusion and 376 (74,90% had more than one objective and more than one conclusion.. CONCLUSIONS: It wasn't found in researched literature the number of objectives and conclusions a scientific work must have. A highest number of thesis and dissertations presented more than one objective and more than one conclusion.
Extremes of 2d Coulomb gas: universal intermediate deviation regime
Lacroix-A-Chez-Toine, Bertrand; Grabsch, Aurélien; Majumdar, Satya N.; Schehr, Grégory
2018-01-01
In this paper, we study the extreme statistics in the complex Ginibre ensemble of N × N random matrices with complex Gaussian entries, but with no other symmetries. All the N eigenvalues are complex random variables and their joint distribution can be interpreted as a 2d Coulomb gas with a logarithmic repulsion between any pair of particles and in presence of a confining harmonic potential v(r) \\propto r2 . We study the statistics of the eigenvalue with the largest modulus r\\max in the complex plane. The typical and large fluctuations of r\\max around its mean had been studied before, and they match smoothly to the right of the mean. However, it remained a puzzle to understand why the large and typical fluctuations to the left of the mean did not match. In this paper, we show that there is indeed an intermediate fluctuation regime that interpolates smoothly between the large and the typical fluctuations to the left of the mean. Moreover, we compute explicitly this ‘intermediate deviation function’ (IDF) and show that it is universal, i.e. independent of the confining potential v(r) as long as it is spherically symmetric and increases faster than \\ln r2 for large r with an unbounded support. If the confining potential v(r) has a finite support, i.e. becomes infinite beyond a finite radius, we show via explicit computation that the corresponding IDF is different. Interestingly, in the borderline case where the confining potential grows very slowly as v(r) ∼ \\ln r2 for r \\gg 1 with an unbounded support, the intermediate regime disappears and there is a smooth matching between the central part and the left large deviation regime.
Move Sequences in Graduate Research Paper Introductions and Conclusions
Madrunio, Marilu Rañosa
2012-01-01
Graduate students submit academic papers at the end of the term as part of their coursework. Such papers contain introduction moves which may be troublesome and conclusion moves which may contain sub-moves not really required. This paper is aimed at assessing what particular moves are employed in the introduction and conclusion sections of 21…
40 CFR 35.6820 - Conclusion of the SSC.
2010-07-01
... STATE AND LOCAL ASSISTANCE Cooperative Agreements and Superfund State Contracts for Superfund Response Actions Requirements for Administering A Superfund State Contract (ssc) § 35.6820 Conclusion of the SSC... (See § 35.6805(i)(4)). (b) After the administrative conclusion of the Superfund State Contract, EPA may...
Direct evidence for a Coulombic phase in monopole-suppressed SU(2) lattice gauge theory
International Nuclear Information System (INIS)
Grady, Michael
2013-01-01
Further evidence is presented for the existence of a non-confining phase at weak coupling in SU(2) lattice gauge theory. Using Monte Carlo simulations with the standard Wilson action, gauge-invariant SO(3)–Z2 monopoles, which are strong-coupling lattice artifacts, have been seen to undergo a percolation transition exactly at the phase transition previously seen using Coulomb gauge methods, with an infinite lattice critical point near β=3.2. The theory with both Z2 vortices and monopoles and SO(3)–Z2 monopoles eliminated is simulated in the strong-coupling (β=0) limit on lattices up to 60 4 . Here, as in the high-β phase of the Wilson-action theory, finite size scaling shows it spontaneously breaks the remnant symmetry left over after Coulomb gauge fixing. Such a symmetry breaking precludes the potential from having a linear term. The monopole restriction appears to prevent the transition to a confining phase at any β. Direct measurement of the instantaneous Coulomb potential shows a Coulombic form with moderately running coupling possibly approaching an infrared fixed point of α∼1.4. The Coulomb potential is measured to 50 lattice spacings and 2 fm. A short-distance fit to the 2-loop perturbative potential is used to set the scale. High precision at such long distances is made possible through the use of open boundary conditions, which was previously found to cut random and systematic errors of the Coulomb gauge fixing procedure dramatically. The Coulomb potential agrees with the gauge-invariant interquark potential measured with smeared Wilson loops on periodic lattices as far as the latter can be practically measured with similar statistics data
Application of screened Coulomb potential in fitting DBV star PG 0112+104
Chen, Y. H.
2018-03-01
With 78.7 d of observations for PG 0112+104, a pulsating DB star, from Campaign 8 of Kepler 2 mission, Hermes et al. made a detailed mode identification. A reliable mode identification, with 5 l = 1 modes, 3 l = 2 modes, and 3 l = 1 or 2 modes, was identified. Grids of DBV star models are evolved by WDEC with element diffusion effect of pure Coulomb potential and screened Coulomb potential. Fitting the identified modes of PG 0112+104 by the calculated ones, we studied the difference of element diffusion effect between adopting pure Coulomb potential and screened Coulomb potential. Our aim is to reduce the fitting error by studying new input physics. The starting models including their chemical composition profile are from white dwarf models evolved by MESA. They were calculated following the stellar evolution from the main sequence to the start of the white dwarf cooling sequences. The optimal parameters are basically consistent with that of previous spectroscopic and asteroseismological studies. The pure and screened Coulomb potential lead to different composition profiles of the C/O-He interface area. High k modes are very sensitive to the area. However, most of the observed modes for PG 0112+104 are low k modes. The σRMS taking the screened Coulomb potential is reduced by 4 per cent compared with taking the pure Coulomb potential when fitting the identified low k modes of PG 0112+104. Fitting the Kepler 2 data with our models improved the σRMS of the fit by 27 per cent.
Hybertsen, Mark S.; Schlüter, Michael; Christensen, Niels E.
1989-05-01
The constrained-density-functional approach is used to calculate the energy surface as a function of local charge fluctuations in La2CuO4. This energy surface is then mapped onto a self-consistent mean-field solution of the Hubbard model which allows extraction of the Coulomb interaction parameters when combined with one-electron parameters derived from band-structure results. Variations in the local Cu d charges and in-plane O p charge are considered for the prototypical high-Tc parent oxide La2CuO4. To isolate the charge fluctuations, the calculations are done in a supercell of size up to 2×2 in the basal plane. The local density-functional calculations are done using the linear muffin-tin orbital approach with the atomic sphere approximation. In the Hubbard Hamiltonian, the Cu d(x2-y2) and O p(x,y) orbitals are included in the pdσ configuration. The one-electron parameters consist of bare on-site energies (ɛp,ɛd) and first-neighbor hopping from Cu to O (tpd) and from O to O (tpp) while the Coulomb-interaction parameters include on-site (Ud,Up) and intersite (Upd,Upp) terms. Results of the present calculation indicate that La2CuO4 is intermediate between the extreme spin or charge fluctuation regimes. This places strong constraints on the available parameter space for theories of high-Tc superconductivity based on the extended Hubbard model.
Ten-year study on acid precipitation nears conclusion
International Nuclear Information System (INIS)
Olem, H.
1990-01-01
Results from the National Acid Precipitation Assessment Program (NAPAP) are discussed. Final results are contained in 26 state of the science reports. Seven of the reports provide information on acid rain and aquatic ecosystems. They describe the current state of acidic surface waters, watershed processes affecting surface water chemistry, historical evidence for surface water acidification, methods for forecasting future changes, and the response of acidic surface water to liming. Six areas of the country were found to be of special interest: southwest Adirondacks, New England, forested areas of the mid-Atlantic highlands, the Atlantic coastal plain, the northern Florida highlands, parts of northeastern Wisconsin and the Upper Peninsula of Michigan. Environmental effects, mitigation efforts and possible legislation are briefly discussed
Physics conclusions in support of ITER W divertor monoblock shaping
Czech Academy of Sciences Publication Activity Database
Pitts, R.A.; Bardin, S.; Bazylev, B.; van den Berg, M.A.; Bunting, P.; Carpentier-Chouchana, S.; Coenen, J.W.; Corre, Y.; Dejarnac, Renaud; Escourbiac, F.; Gaspar, J.; Gunn, J. P.; Hirai, T.; Hong, S.-H.; Horáček, Jan; Iglesias, D.; Komm, Michael; Krieger, K.; Lasnier, C.; Matthews, G.F.; Morgan, T.W.; Panayotis, S.; Pestchanyi, S.; Podolník, Aleš; Nygren, R.E.; Rudakov, D.L.; De Temmerman, G.; Vondráček, Petr; Watkins, J.G.
2017-01-01
Roč. 12, August (2017), s. 60-74 ISSN 2352-1791. [International Conference on Plasma Surface Interactions 2016, PSI2016 /22./. Roma, 30.05.2016-03.06.2016] Institutional support: RVO:61389021 Keywords : ITER * Tungsten * Divertor * Shaping * Melting * MEMOS Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics) http://www.sciencedirect.com/science/article/pii/S2352179116302885
The three-point function in split dimensional regularization in the Coulomb gauge
Leibbrandt, G
1998-01-01
We use a gauge-invariant regularization procedure, called ``split dimensional regularization'', to evaluate the quark self-energy $\\Sigma (p)$ and quark-quark-gluon vertex function $\\Lambda_\\mu (p^\\prime,p)$ in the Coulomb gauge, $\\vec{\\bigtriangledown}\\cdot\\vec{A}^a = 0$. The technique of split dimensional regularization was designed to regulate Coulomb-gauge Feynman integrals in non-Abelian theories. The technique which is based on two complex regulating parameters, $\\omega$ and $\\sigma$, is shown to generate a well-defined set of Coulomb-gauge integrals. A major component of this project deals with the evaluation of four-propagator and five-propagator Coulomb integrals, some of which are nonlocal. It is further argued that the standard one-loop BRST identity relating $\\Sigma$ and $\\Lambda_\\mu$, should by rights be replaced by a more general BRST identity which contains two additional contributions from ghost vertex diagrams. Despite the appearance of nonlocal Coulomb integrals, both $\\Sigma$ and $\\Lambda_\\...
Coulomb Fourier transformation: A novel approach to three-body scattering with charged particles
International Nuclear Information System (INIS)
Alt, E.O.; Levin, S.B.; Yakovlev, S.L.
2004-01-01
A unitary transformation of the three-body Hamiltonian which describes a system of two charged and one neutral particles is constructed such that the Coulomb potential which acts between the charged particles is explicitly eliminated. The transformed Hamiltonian and, in particular, the transformed short-range pair interactions are worked out in detail. Thereby it is found that, after transformation, the short-range potentials acting between the neutral and either one of the charged particles become simply Fourier transformed but, in addition, multiplied by a function that represents the Coulombic three-body correlations originating from the action of the other charged particle on the considered pair. This function which is universal as it does not depend on any property of the short-range interaction is evaluated explicitly and its singularity structure is described in detail. In contrast, the short-range potential between the charged particles remains of two-body type but occurs now in the 'Coulomb representation'. Specific applications to Yukawa and Gaussian potentials are given. Since the Coulomb-Fourier-transformed Hamiltonian does no longer contain the Coulomb potential or any other effective interaction of long range, standard methods of short-range few-body scattering theory are applicable
Energy Technology Data Exchange (ETDEWEB)
Dimits, A M; Wang, C; Caflisch, R; Cohen, B I; Huang, Y
2008-08-06
We investigate the accuracy of and assumptions underlying the numerical binary Monte-Carlo collision operator due to Nanbu [K. Nanbu, Phys. Rev. E 55 (1997)]. The numerical experiments that resulted in the parameterization of the collision kernel used in Nanbu's operator are argued to be an approximate realization of the Coulomb-Lorentz pitch-angle scattering process, for which an analytical solution for the collision kernel is available. It is demonstrated empirically that Nanbu's collision operator quite accurately recovers the effects of Coulomb-Lorentz pitch-angle collisions, or processes that approximate these (such interspecies Coulomb collisions with very small mass ratio) even for very large values of the collisional time step. An investigation of the analytical solution shows that Nanbu's parameterized kernel is highly accurate for small values of the normalized collision time step, but loses some of its accuracy for larger values of the time step. Careful numerical and analytical investigations are presented, which show that the time dependence of the relaxation of a temperature anisotropy by Coulomb-Lorentz collisions has a richer structure than previously thought, and is not accurately represented by an exponential decay with a single decay rate. Finally, a practical collision algorithm is proposed that for small-mass-ratio interspecies Coulomb collisions improves on the accuracy of Nanbu's algorithm.
Room temperature Coulomb blockade mediated field emission via self-assembled gold nanoparticles
Energy Technology Data Exchange (ETDEWEB)
Wang, Fei [College of Physics and Electronics, Central South University, Changsha, Hunan 410073 (China); College of Science, National University of Defense Technology, Changsha, Hunan 410073 (China); Fang, Jingyue, E-mail: fjynudt@aliyun.com [College of Science, National University of Defense Technology, Changsha, Hunan 410073 (China); Chang, Shengli; Qin, Shiqiao; Zhang, Xueao [College of Science, National University of Defense Technology, Changsha, Hunan 410073 (China); Xu, Hui, E-mail: cmpxhg@csu.edu.cn [College of Physics and Electronics, Central South University, Changsha, Hunan 410073 (China)
2017-02-05
Coulomb blockade mediated field-emission current was observed in single-electron tunneling devices based on self-assembled gold nanoparticles at 300 K. According to Raichev's theoretical model, by fixing a proper geometric distribution of source, island and drain, the transfer characteristics can be well explained through a combination of Coulomb blockade and field emission. Coulomb blockade and field emission alternately happen in our self-assembled devices. The Coulomb island size derived from the experimental data is in good agreement with the average size of the gold nanoparticles used in the device. The integrated tunneling can be adjusted via a gate electrode. - Highlights: • The phenomenon of single-electron field emission in a transistor setting using self-assembled gold nanoparticles was investigated. • The transfer characteristics can be well explained by the model that is a combination of Coulomb blockage and field emission. • This transport mechanism is novel and may be used in many applications in field emission devices.
Sensitivity of electrospray molecular dynamics simulations to long-range Coulomb interaction models
Mehta, Neil A.; Levin, Deborah A.
2018-03-01
Molecular dynamics (MD) electrospray simulations of 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIM-BF4) ion liquid were performed with the goal of evaluating the influence of long-range Coulomb models on ion emission characteristics. The direct Coulomb (DC), shifted force Coulomb sum (SFCS), and particle-particle particle-mesh (PPPM) long-range Coulomb models were considered in this work. The DC method with a sufficiently large cutoff radius was found to be the most accurate approach for modeling electrosprays, but, it is computationally expensive. The Coulomb potential energy modeled by the DC method in combination with the radial electric fields were found to be necessary to generate the Taylor cone. The differences observed between the SFCS and the DC in terms of predicting the total ion emission suggest that the former should not be used in MD electrospray simulations. Furthermore, the common assumption of domain periodicity was observed to be detrimental to the accuracy of the capillary-based electrospray simulations.
Study of the nuclear-coulomb low-energy scattering parameters on the basis of the p-matrix approach
International Nuclear Information System (INIS)
Babenko, V.A.; Petrov, N.M.
1993-01-01
The P-matrix approach application to the description of two charged strongly interacting particles nuclear-Coulomb scattering parameters is considered. The nuclear-Coulomb scattering length and effective range explicit expressions in terms of the P-matrix parameters are found. The nuclear-Coulomb low-energy parameters expansions in powers of small parameter β ≡ R/a b , involving terms with big logarithms, are obtained. The nuclear-Coulomb scattering length and effective range for the square-well and the delta-shell short range potentials are found in an explicit form. (author). 21 refs
Conclusiveness of natural languages and recognition of images
Energy Technology Data Exchange (ETDEWEB)
Wojcik, Z.M.
1983-01-01
The conclusiveness is investigated using recognition processes and one-one correspondence between expressions of a natural language and graphs representing events. The graphs, as conceived in psycholinguistics, are obtained as a result of perception processes. It is possible to generate and process the graphs automatically, using computers and then to convert the resulting graphs into expressions of a natural language. Correctness and conclusiveness of the graphs and sentences are investigated using the fundamental condition for events representation processes. Some consequences of the conclusiveness are discussed, e.g. undecidability of arithmetic, human brain assymetry, correctness of statistical calculations and operations research. It is suggested that the group theory should be imposed on mathematical models of any real system. Proof of the fundamental condition is also presented. 14 references.
External Coulomb-Friction Damping For Hydrostatic Bearings
Buckmann, Paul S.
1992-01-01
External friction device damps vibrations of shaft and hydrostatic ring bearing in which it turns. Does not rely on wear-prone facing surfaces. Hydrostatic bearing ring clamped in radially flexing support by side plates clamped against radial surfaces by spring-loaded bolts. Plates provide friction against radial motions of shaft.
Factors affecting profit in dairying: conclusions from Natal study ...
African Journals Online (AJOL)
Factors affecting profit in dairying: conclusions from Natal study group results. P.G. Stewart. Abstract. No Abstract. Full Text: EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT · AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians ...
29 CFR 417.12 - Proposed findings and conclusions.
2010-07-01
...-MANAGEMENT STANDARDS PROCEDURE FOR REMOVAL OF LOCAL LABOR ORGANIZATION OFFICERS Procedures To Determine Adequacy of Constitution and Bylaws for Removal of Officers of Local Labor Organizations § 417.12 Proposed... proposed findings and conclusions to the Administrative Law Judge, together with supporting reasons...
20 CFR 901.48 - Proposed findings and conclusions.
2010-04-01
... Law Judge, before making his/her decision, shall give the parties a reasonable opportunity to submit... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Proposed findings and conclusions. 901.48 Section 901.48 Employees' Benefits JOINT BOARD FOR THE ENROLLMENT OF ACTUARIES REGULATIONS GOVERNING THE...
Hypothesis, Prediction, and Conclusion: Using Nature of Science Terminology Correctly
Eastwell, Peter
2012-01-01
This paper defines the terms "hypothesis," "prediction," and "conclusion" and shows how to use the terms correctly in scientific investigations in both the school and science education research contexts. The scientific method, or hypothetico-deductive (HD) approach, is described and it is argued that an understanding of the scientific method,…
Actual Problems of Conclusion and Discharge of Urgent Labour Contracts
Directory of Open Access Journals (Sweden)
Shevelyova A. A.
2013-05-01
Full Text Available This article is devoted to the consideration of the questions connected with the conclusion and the termination of the urgent labour contract. The author, analyzing judicial practice, allocates the problems of separate regulation of the RF labour legislation enforcement.
Directory of Open Access Journals (Sweden)
Caravaca Garratón Manuel
2017-07-01
Full Text Available In this paper, we shall illustrate the numerical calculation of the effective temperature in Coulomb glasses by excitation probability provided that the system has been placed in a stationary state after applying a strong electric field. The excitation probability becomes a better alternative than the occupation probability, which has been classically employed to calculate the effective temperature and characterize the thermodynamics of Coulomb glasses out of equilibrium. This is due to the fact that the excitation probability shows better statistics than the occupation probability. In addition, our simulations show that the excitation probability does not depend on the choice of the chemical potential, which critically affects the occupation probability. Our results allow us to propose the excitation probability as a standard procedure to determine the effective temperature in Coulomb glasses as well as in other complex systems such as spin glasses.
Partial breaking of the Coulombic ordering of ionic liquids confined in carbon nanopores.
Futamura, Ryusuke; Iiyama, Taku; Takasaki, Yuma; Gogotsi, Yury; Biggs, Mark J; Salanne, Mathieu; Ségalini, Julie; Simon, Patrice; Kaneko, Katsumi
2017-12-01
Ionic liquids are composed of equal quantities of positive and negative ions. In the bulk, electrical neutrality occurs in these liquids due to Coulombic ordering, in which ion shells of alternating charge form around a central ion. Their structure under confinement is far less well understood. This hinders the widespread application of ionic liquids in technological applications. Here we use scattering experiments to resolve the structure of a widely used ionic liquid (EMI-TFSI) when it is confined inside nanoporous carbons. We show that Coulombic ordering reduces when the pores can accommodate only a single layer of ions. Instead, equally charged ion pairs are formed due to the induction of an electric potential of opposite sign in the carbon pore walls. This non-Coulombic ordering is further enhanced in the presence of an applied external electric potential. This finding opens the door for the design of better materials for electrochemical applications.
Structure effects on the Coulomb dissociation of {sup 8}B at relativistic energies
Energy Technology Data Exchange (ETDEWEB)
Shyam, R. [Saha Inst. of Nuclear Physics, Calcutta (India); Bennaceur, K.; Okolowicz, J.; Ploszajczak, M. [Grand Accelerateur National d' Ions Lourds (GANIL), 14 - Caen (France)
1999-07-01
The Coulomb dissociation of {sup 8}B on {sup 208}Pb target at the beam energy of 250 MeV/nucleon is investigated, employing the cross sections for the radiative capture reaction {sup 7}Be(p,{gamma}){sup 8}B calculated within the Shell Model Embedded in the Continuum (SMEC) approach. In contrast to the situation at lower beam energies, the Coulomb breakup cross sections are found to be sensitive to the M1 transitions. Comparisons of SMEC and single-particle potential model predictions show that the Coulomb breakup cross sections at these high energies are sensitive to the structure model of {sup 8}B. Analysis of the preliminary data taken recently at GSI reveal that E2 multipolarity contributes up to 25% to the cross sections even for the relative energies of p - {sup 7}Be below 0.25 MeV. (author)
Hamiltonian approach to QCD in Coulomb gauge: Gribov’s confinement scenario at work*
Directory of Open Access Journals (Sweden)
Reinhardt H.
2017-01-01
Full Text Available I will review essential features of the Hamiltonian approach to QCD in Coulomb gauge showing that Gribov's confinement scenario is realized in this gauge. For this purpose I will discuss in detail the emergence of the horizon condition and the Coulomb string tension. I will show that both are induced by center vortex gauge field configurations, which establish the connection between Gribov’s confinement scenario and the center vortex picture of confinement. I will then extend the Hamiltonian approach to QCD in Coulomb gauge to finite temperatures, first by the usual grand canonical ensemble and second by the compactification of a spatial dimension. I will present results for the pressure, energy density and interaction measure as well as for the Polyakov loop.
Hamiltonian approach to QCD in Coulomb gauge: Gribov's confinement scenario at work
Reinhardt, H.; Burgio, G.; Campagnari, D.; Quandt, M.; Vastag, P.; Vogt, H.; Ebadati, E.
2017-12-01
I will review essential features of the Hamiltonian approach to QCD in Coulomb gauge showing that Gribov's confinement scenario is realized in this gauge. For this purpose I will discuss in detail the emergence of the horizon condition and the Coulomb string tension. I will show that both are induced by center vortex gauge field configurations, which establish the connection between Gribov's confinement scenario and the center vortex picture of confinement. I will then extend the Hamiltonian approach to QCD in Coulomb gauge to finite temperatures, first by the usual grand canonical ensemble and second by the compactification of a spatial dimension. I will present results for the pressure, energy density and interaction measure as well as for the Polyakov loop.
Coulomb excitation of neutron-deficient polonium isotopes studied at ISOLDE
Neven, Michiel
The polonium isotopes represent an interesting region of the nuclear chart having only two protons outside the Z = 82 closed shell. These isotopes have already been extensively studied theoretically and experimentally. The heavier isotopes (A > 200) seem to follow a "regular seniority-type regime" while for the lighter isotopes (A < 200) a more collective behavior is observed. Many questions remain regarding the transition between these two regimes and the configuration mixing between quantum states. Experiments in the lighter polonium isotopes point to the presence of shape coexistence, however the phenomenon is not fully understood. A Coulomb excitation study of the polonium isotopes whereby the dynamic properties are investigated can provide helpful insights in understanding the shape coexistence phenomena. In this thesis $^{202}$Po was studied via Coulomb excitation. The $^{202}$Po isotope was part of an experimental campaign in which the $^{196,198,200,206}$Po isotopes were studied as well via Coulomb...
Partial breaking of the Coulombic ordering of ionic liquids confined in carbon nanopores
Futamura, Ryusuke; Iiyama, Taku; Takasaki, Yuma; Gogotsi, Yury; Biggs, Mark J.; Salanne, Mathieu; Ségalini, Julie; Simon, Patrice; Kaneko, Katsumi
2017-12-01
Ionic liquids are composed of equal quantities of positive and negative ions. In the bulk, electrical neutrality occurs in these liquids due to Coulombic ordering, in which ion shells of alternating charge form around a central ion. Their structure under confinement is far less well understood. This hinders the widespread application of ionic liquids in technological applications. Here we use scattering experiments to resolve the structure of a widely used ionic liquid (EMI-TFSI) when it is confined inside nanoporous carbons. We show that Coulombic ordering reduces when the pores can accommodate only a single layer of ions. Instead, equally charged ion pairs are formed due to the induction of an electric potential of opposite sign in the carbon pore walls. This non-Coulombic ordering is further enhanced in the presence of an applied external electric potential. This finding opens the door for the design of better materials for electrochemical applications.
Debris impact on emergency coolant recirculation - summary and conclusions
International Nuclear Information System (INIS)
Jain, Bhagwat; Hsia, Anthony; Armand, Yves; Mattei, Jean-Marie; Hyvaerinen, Juhani; Maqua, Michael; Puetter, Bernhard; Sandervaag, Oddbjoern; Vandewalle, Andre; Tombuyses, Beatrice; Pyy, Pekka; Royen, Jacques
2004-01-01
to two orders of magnitude because of strainer clogging. Consequently, the CSNI decided to continue its previous efforts in the area. The overall purpose of the 2004 Workshop was to discuss the impact of new information made available since 1996 and to promote consensus among member countries on identification of remaining technical issues important to safety, and on possible paths for their resolution. The specific purposes of the Workshop were: a. To review the knowledge base and in particular information developed after 1999, and to consider the validity of the conclusions drawn. b. To exchange information on the current status of research related to debris generation, debris transportation, and sump strainer clogging and penetration phenomena, in particular for PWRs, and to assess uncertainties. c. To exchange and disseminate information on recent and current activities and practices in these areas. d. To identify and discuss differences between approaches relevant to reactor safety. e. To identify technical issues and programs of interest for international collaborative research and develop an Action Plan outlining activities that CSNI should undertake in the area of strainer or sump screen clogging during the next few years. Summary of the main findings: a. The safety significance of the sump strainer clogging depends on the plant design (e.g. sump strainer, ECCS) and backfitting measures performed. b. The following are examples of PWR design features that could influence the debris impact on the ECCS sump performance: - Type of insulation (material, combination of materials, protection). - Break size to be postulated. - Transport in containment with or without containment spray system (CSS). - Degree of turbulence and flow velocities in the sump influenced by CSS, water level, break flow location and sump geometry. - Redundancy of sumps and residual heat removal system (RHRS). - Strainer design (area, mesh size). - Positioning of recirculation pumps and vortex
150 Years of Coulomb Stress History Along the California-Nevada Border, USA.
Carena, S.; Verdecchia, A.
2014-12-01
The temporal and spatial correlation among earthquakes in diffuse plate boundary zones is not well understood yet. The region north of the Garlock fault between the Sierra Nevada and Death Valley is part of a diffuse plate boundary zone, which absorbs a significant fraction of the plate motion between Pacific and North America. This area has experienced at least eight Mw ≥ 6 earthquakes in historical times, beginning with the 1872 Mw 7.5 Owens Valley earthquake. Furthermore, since 1978 Long Valley caldera has been undergoing periods of unrest, with earthquake swarms and resurgence. Our goal is to determine whether the 1872 Owens Valley earthquake has influenced the seismicity and volcanic activity in the area. We model the evolution of coseismic, interseismic and postseismic Coulomb stress (ΔCFS) in the region due to both earthquakes and caldera activity in the last 150 years. Our results show that the 1872 Owens Valley earthquake strongly encourages faulting in northern Owens Valley. In addition, there is a correlation among smaller events, in the form of a west-to-east migration of earthquakes from Long Valley caldera toward the White Mountains immediately following the 1978 caldera inflation event. The last event in this sequence, the 1986 Mw 6.3 Chalfant Valley earthquake, controls the location of over 80% of its own aftershocks, which occur in areas of positive ΔCFS and reach Mw 5.7. We also calculate the cumulative ΔCFS on several major active faults in the region. Stresses up to 30 bars and 10 bars respectively have accumulated on the White Mountains (Central section) and Deep Springs faults, comparable to the expected stress drop in an average earthquake. Because no surface ruptures more recent than 1.8 ka have been identified on these faults [dePolo, 1989; Lee et al., 2001], we consider them as likely candidates for the next major earthquake in the region.
Cosmological Gamma-Ray Bursts and Hypernovae Conclusively Linked
2003-06-01
Clearest-Ever Evidence from VLT Spectra of Powerful Event Summary A very bright burst of gamma-rays was observed on March 29, 2003 by NASA's High Energy Transient Explorer (HETE-II) , in a sky region within the constellation Leo. Within 90 min, a new, very bright light source (the "optical afterglow") was detected in the same direction by means of a 40-inch telescope at the Siding Spring Observatory (Australia) and also in Japan. The gamma-ray burst was designated GRB 030329 , according to the date. And within 24 hours, a first, very detailed spectrum of this new object was obtained by the UVES high-dispersion spectrograph on the 8.2-m VLT KUEYEN telescope at the ESO Paranal Observatory (Chile). It allowed to determine the distance as about 2,650 million light-years (redshift 0.1685). Continued observations with the FORS1 and FORS2 multi-mode instruments on the VLT during the following month allowed an international team of astronomers [1] to document in unprecedented detail the changes in the spectrum of the optical afterglow of this gamma-ray burst . Their detailed report appears in the June 19 issue of the research journal "Nature". The spectra show the gradual and clear emergence of a supernova spectrum of the most energetic class known, a "hypernova" . This is caused by the explosion of a very heavy star - presumably over 25 times heavier than the Sun. The measured expansion velocity (in excess of 30,000 km/sec) and the total energy released were exceptionally high, even within the elect hypernova class. From a comparison with more nearby hypernovae, the astronomers are able to fix with good accuracy the moment of the stellar explosion. It turns out to be within an interval of plus/minus two days of the gamma-ray burst. This unique conclusion provides compelling evidence that the two events are directly connected. These observations therefore indicate a common physical process behind the hypernova explosion and the associated emission of strong gamma
Hamiltonian approach to QCD in Coulomb gauge at zero and finite temperature
Directory of Open Access Journals (Sweden)
Reinhardt H.
2017-01-01
Full Text Available I report on recent results obtained within the Hamiltonian approach to QCD in Coulomb gauge. By relating the Gribov confinement scenario to the center vortex picture of confinement it is shown that the Coulomb string tension is tied to the spatial string tension. For the quark sector a vacuum wave functional is used which results in variational equations which are free of ultraviolet divergences. The variational approach is extended to finite temperatures by compactifying a spatial dimension. For the chiral and deconfinement phase transition pseudo-critical temperatures of 170MeV and 198 MeV, respectively, are obtained.
International Nuclear Information System (INIS)
Tyukhtyaev, Yu.N.
1982-01-01
The problem of taking into account the Coulomb interaction of the ladder type in the analysis of bound states in quantum electrodynamics is discussed in the framework of the quasipotential approach. The main qiasipotential equation and the quasipotential are expressed in the terms of the two-time positive frequency Coulomb Green functions. The corresponding perturbation theory is developed which makes it possible to calculate the shifts of the energy levels in hydrogen-like atoms up to α 6 lnα terms
A rate-dependent Hosford-Coulomb model for predicting ductile fracture at high strain rates
Directory of Open Access Journals (Sweden)
Marcadet Stephane J.
2015-01-01
Full Text Available The Hosford-Coulomb model incorporates the important effect of the Lode angle parameter in addition to the stress triaxiality to predict the initiation of ductile fracture. A strain-rate dependent extension of the Hosford-Coulomb model is presented to describe the results from low, intermediate and high strain rate fracture experiments on advanced high strength steels (DP590 and TRIP780. The model predictions agree well with the experimental observation of an increase in ductility as function of strain rate for stress states ranging from uniaxial to equi-biaxial tension.
SYMMETRY PROPERTIES OF THE COULOMB POTENTIAL WITH A LINEAR DEPENDENCE ON ENERGY
Directory of Open Access Journals (Sweden)
Radu Budaca
2017-12-01
Full Text Available The D-dimensional Schr ̈odinger equation for a Coulomb potential with a coupling constant depending linearly on energy is analytically solved. The energy spectrum in the asymptotic regime of the slope parameter is found to be fully determined up to a scale only by its quantum numbers. The raising and lowering operators for this limiting model are determined from the recurrence properties of the associated solutions. It is shown that they satisfy the commutation relations of an SU(1,1 algebra and act on wave-functions which are normalized differently from the case of the usual bound state problem for an energy independent Coulomb potential.
Limits on Lorentz Invariance Violation from Coulomb Interactions in Nuclei and Atoms.
Flambaum, V V; Romalis, M V
2017-04-07
Anisotropy in the speed of light that has been constrained by Michelson-Morley-type experiments also generates anisotropy in the Coulomb interactions. This anisotropy can manifest itself as an energy anisotropy in nuclear and atomic experiments. Here the experimental limits on Lorentz violation in _{10}^{21}Ne are used to improve the limits on Lorentz symmetry violations in the photon sector, namely, the anisotropy of the speed of light and the Coulomb interactions, by 7 orders of magnitude in comparison with previous experiments: the speed of light is isotropic to a part in 10^{28}.
Stability of the three-body Coulomb systems with J=1 in the oscillator representation
International Nuclear Information System (INIS)
Dinejkhan, M.D.; Efimov, G.V.
1995-01-01
The oscillator representation is applied to calculate the energy spectrum of three-body Coulomb systems with J total angular momentum. For the three-body Coulomb systems with J=1 and arbitrary masses the region of stability is determined. For the systems (A + A - e - ), (pe - C + ), (pB - e - ) and (D + e - e + ), the values for the critical masses of A-, B-, C- and D-particles are obtained: m A =2.22m e , m B =1.49m e , m C =2.11m e and m D =4.15m e . 18 refs., 1 fig., 3 tabs
Energy Technology Data Exchange (ETDEWEB)
Kolenda, Stefan; Wolf, Michael J.; Beckmann, Detlef [Institut fuer Nanotechnologie, KIT, 76021 Karlsruhe (Germany)
2013-07-01
In normalmetal/superconductor hybrid structures nonlocal conductance is determined by crossed Andreev reflection (CAR) and elastic cotunneling (EC). This was investigated recently both experimentally and theoretically. Dynamical Coulomb blockade of EC and CAR was predicted theoretically. Here we report on experimental investigations of these effects. We found signatures of dynamical Coulomb blockade in local and nonlocal conductance in the normal state. In the superconducting state, we find s-shaped nonlocal differential conductance curves as a function of bias applied on both contacts. These curves were observed for bias voltages both below and above the gap. We compare our results to theory.
Importance of Coulomb interactions in bound-to-continuum THz quantum cascade lasers
Energy Technology Data Exchange (ETDEWEB)
Jirauschek, C; Matyas, A [Emmy Noether Research Group ' Modeling of Quantum Cascade Devices' , Technische Universitaet Muenchen, D-80333 Munich (Germany); Lugli, P, E-mail: jirauschek@tum.d [Institute for Nanoelectronics, Technische Universitaet Muenchen, D-80333 Munich (Germany)
2009-11-15
We demonstrate the importance of Coulomb interactions in bound-to-continuum THz quantum cascade lasers, employing an ensemble Monte-Carlo analysis. In such structures, the electron-electron interactions between the closely spaced energy levels in the minibands tend to play a more important role than in resonant-phonon depopulation designs, where the energy levels are more energetically separated and LO phonon scattering prevails. Also a significant conduction band bending due to space charge effects is observed. Thus, especially for bound-to-continuum structures careful modelling of Coulomb interactions is crucial to obtain good agreement with experiment.
Coulomb excitation of $^{68}_{28}Ni_{40}$ at safe energies
Bree, N; Butler, P A; Cederkäll, J; Davinson, T; Delahaye, P; Eberth, J; Fedorov, D; Fedosseev, V; Fraile, L M; Franchoo, S; Georgiev, G; Gladnishki, K; Huyse, M; Ivanov, O; Iwanicki, J; Jolie, J; Köster, U; Kröll, T; Krücken, R; Marsh, B A; Niedermaier, O; Reiter, P; Scheit, H; Schwalm, D; Sieber, T; Vande Walle, J; Van Duppen, P; Warr, N; Weisshaar, D; Wenander, F; Zemlyanoy, S; Instituutvoor Kern-en Stralingsfysica; Leuven, K U
2008-01-01
The $B(E2;0^+\\to2^+)$ value in $^{68}$Ni has been measured using Coulomb excitation at safe energies. The $^{68}$Ni radioactive beam was post-accelerated at the ISOLDE facility (CERN) to 2.9 MeV/u. The emitted $\\gamma$ rays were detected by the MINIBALL detector array. A kinematic particle reconstruction was performed in order to increase the measured c.m. angular range of the excitation cross section. The obtained value of 2.8$\\pm$1.0 10$^2$ e$^2$fm$^4$ is in good agreement with the value measured at intermediate energy Coulomb excitation, confirming the low transition probability.
Optimal Tuning of Amplitude Proportional Coulomb Friction Damper for Maximum Cable Damping
DEFF Research Database (Denmark)
Weber, Felix; Høgsberg, Jan Becker; Krenk, Steen
2010-01-01
This paper investigates numerically the optimal tuning of Coulomb friction dampers on cables, where the optimality criterion is maximum additional damping in the first vibration mode. The expression for the optimal friction force level of Coulomb friction dampers follows from the linear viscous...... is estimated. It is found that the damping efficiency agrees well with the expected value at the theoretical optimum. However, maximum damping is larger and achieved at a force to amplitude ratio of 1.4 times the analytical value. Investigations show that the increased damping results from energy spillover...
Mesoscopic fluctuations of Coulomb drag between quasiballistic one-dimensional wires
DEFF Research Database (Denmark)
Mortensen, Asger; Flensberg, Karsten; Jauho, Antti-Pekka
2002-01-01
Quasiballistic one-dimensional quantum wires are known to have a conductance of the order of 2e(2)/h, with small sample-to-sample fluctuations. We present a study of the transconductance G(12) Of two Coulomb-coupled quasiballistic wires; i.e., we consider the Coulomb drag geometry. We show...... that the fluctuations in G(12) differ dramatically from those of the diagonal conductance G(ii): the fluctuations are large and can even exceed the mean value, thus implying a possible reversal of the induced drag current. We report extensive numerical simulations elucidating the fluctuations for both correlated...
Urban Transport Dysfunction and Air Pollution in Dakar : Study Conclusions
Bultynck Patrick
2001-01-01
This Note presents the main conclusions of an on-site study of urban transport dysfunction and air pollution in the Dakar agglomeration carried out from August to November 1998. The study aims to define the main causes of transport dysfunction, quantify them, and recommend a suitable framework for monitoring changes in the parameters. This forms part of the sub-Saharan African air quality ...
Biogeochemistry of uranium mill wastes program overview and conclusions
International Nuclear Information System (INIS)
Dreesen, D.R.
1981-05-01
The major findings and conclusions are summarized for research on uranium mill tailings for the US Department of Energy and the US Nuclear Regulatory Commission. An overview of results and interpretations is presented for investigations of 222 Rn emissions, revegetation of tailings and mine spoils, and trace element enrichment, mobility, and bioavailability. A brief discussion addresses the implications of these findings in relation to tailings disposal technology and proposed uranium recovery processes
Review conclusions by Ernst and Canter regarding spinal manipulation refuted
Directory of Open Access Journals (Sweden)
Evans Roni
2006-08-01
Full Text Available Abstract In the April 2006 issue of the Journal of Royal Society of Medicine, Ernst and Canter authored a review of the most recent systematic reviews on the effectiveness of spinal manipulation for any condition. The authors concluded that, except for back pain, spinal manipulation is not an effective intervention for any condition and, because of potential side effects, cannot be recommended for use at all in clinical practice. Based on a critical appraisal of their review, the authors of this commentary seriously challenge the conclusions by Ernst and Canter, who did not adhere to standard systematic review methodology, thus threatening the validity of their conclusions. There was no systematic assessment of the literature pertaining to the hazards of manipulation, including comparison to other therapies. Hence, their claim that the risks of manipulation outweigh the benefits, and thus spinal manipulation cannot be recommended as treatment for any condition, was not supported by the data analyzed. Their conclusions are misleading and not based on evidence that allow discrediting of a large body of professionals using spinal manipulation.
^{11}Li Breakup on ^{208}Pb at Energies Around the Coulomb Barrier
DEFF Research Database (Denmark)
Fernández-García, J.P.; Cubero, M.; Rodríguez-Gallardo, M.
2013-01-01
The inclusive breakup for the 11Li+208Pb reaction at energies around the Coulomb barrier has been measured for the first time. A sizable yield of 9Li following the 11Li dissociation has been observed, even at energies well below the Coulomb barrier. Using the first-order semiclassical perturbatio...
Physics conclusions in support of ITER W divertor monoblock shaping
Directory of Open Access Journals (Sweden)
R.A. Pitts
2017-08-01
Full Text Available The key remaining physics design issue for the ITER tungsten (W divertor is the question of monoblock (MB front surface shaping in the high heat flux target areas of the actively cooled targets. Engineering tolerance specifications impose a challenging maximum radial step between toroidally adjacent MBs of 0.3mm. Assuming optical projection of the parallel heat loads, magnetic shadowing of these edges is required if quasi-steady state melting is to be avoided under certain conditions during burning plasma operation and transiently during edge localized mode (ELM or disruption induced power loading. An experiment on JET in 2013 designed to investigate the consequences of transient W edge melting on ITER, found significant deficits in the edge power loads expected on the basis of simple geometric arguments, throwing doubt on the understanding of edge loading at glancing field line angles. As a result, a coordinated multi-experiment and simulation effort was initiated via the International Tokamak Physics Activity (ITPA and through ITER contracts, aimed at improving the physics basis supporting a MB shaping decision from the point of view both of edge power loading and melt dynamics. This paper reports on the outcome of this activity, concluding first that the geometrical approximation for leading edge power loading on radially misaligned poloidal leading edges is indeed valid. On this basis, the behaviour of shaped and unshaped monoblock surfaces under stationary and transient loads, with and without melting, is compared in order to examine the consequences of melting, or power overload in context of the benefit, or not, of shaping. The paper concludes that MB top surface shaping is recommended to shadow poloidal gap edges in the high heat flux areas of the ITER divertor targets.
It pays to be green. A premature conclusion?
International Nuclear Information System (INIS)
Telle, K.
2006-01-01
It has been claimed that good environmental performance can improve firms' economic performance. However, because of e.g. data limitations, the methods applied in most previous quantitative empirical studies on effects of environmental performance on economic performance of firms suffer from several shortcomings. We discuss these shortcomings and conclude that previously applied methods are unsatisfactory as support for a conclusion that it pays for firms to be green. Then we illustrate the consequences of these shortcomings by performing several regression analyses of the effect of environmental performance on economic performance using a panel data set of Norwegian plants. A pooled regression where observable firm characteristics like e.g. size or industry are controlled for, confirms a positive effect of environmental performance on economic performance. However, the estimated positive effect could be due to omitted unobserved variables like management or technology. When the regression model controls for unobserved plant heterogeneity, the effect is generally no longer statistically significant. Hence, although greener plants tend to perform economically better, the analysis provides little support for the claim that it is because they are greener. These empirical findings further indicate that a conclusion that it pays to be green is premature
Results and conclusions of stress measurements at Stripa
International Nuclear Information System (INIS)
Doe, T.W.; Hustrulid, W.A.; Leijon, B.; Ingevald, K.; Strindell, L.; Carlsson, H.
1982-10-01
This paper describes the results of stress measurements at Stripa, compares the results obtained by different techniques, and recommends a stress measurement program for a hard rock repository site. The state of stress at the Stripa Mine has been measured both in a 381-m-deep hole drilled from the surface and in holes drilled from the drifts underground. Hydraulic fracturing and several overcoring methods have been used (Lulea triaxial gauge, CSIRO gauge, USBM gauge, Swedish State Power Board deep-hole Leeman triaxial gauge). The results of overcoring and hydraulic fracturing agree well, particularly for the magnitude and orientation of the greatest stress. A recommended program for stress measurement at a repository site would include hydraulic fracturing and deep-hole overcoring in a deep hole drilled from surface, and overcoring (Lulea gauge and USBM gauge) and hydraulic fracturing from holes drilled from underground openings when access is available. Propagation of the hydraulic fractures should be monitored acoustically to determine their location and orientation
Nuclear reactions of the system 6 Li on 58 Ni near the Coulomb barrier
International Nuclear Information System (INIS)
Lizcano, D.; Aguilera, E.F.; Garcia M, H.; Martinez Q, E.
2004-01-01
Protons, alpha particles and deuterons coming from the reactions 6 Li + 58 Ni are detected to three different energy around the Coulomb barrier. The possible effects of the weakly bound character of the projectile are studied and the results are compared with previous data for the system 6 Li + 59 Co. (Author)
Lienard-Wiechert potentials as a consequence of Lorentz transformation of Coulomb potential
International Nuclear Information System (INIS)
Strel'tsov, V.N.
1993-01-01
A derivation of the electric potential of a moving charge as a result of the 'relativization' of the Coulomb potential is considered. The account of the Lorentz covariance demand and the action retardation of the electromagnetic field with necessity leads to the Lienard-Wiechert potentials. 11 refs. (author)
Effect of Coulomb correlations on the electronic structure of PuCoGa.sub.5./sub.
Czech Academy of Sciences Publication Activity Database
Shick, Alexander; Janiš, Václav; Oppeneer, P.M.
2005-01-01
Roč. 94, č. 1 (2005), 016401/1-016401/4 ISSN 0031-9007 R&D Projects: GA ČR(CZ) GA202/04/1055 Institutional research plan: CEZ:AV0Z10100520 Keywords : Coulomb correlations * PuCoGa 5 Subject RIV: BE - Theoretical Physics Impact factor: 7.489, year: 2005
Nonlocal Coulomb interaction in the two-dimensional spin-1/2 ...
Indian Academy of Sciences (India)
pp. 289–296. Nonlocal Coulomb interaction in the two-dimensional spin-1/2 Falicov–Kimball model. S K BHOWMICK and N K GHOSH. ∗. Department of Physics, University of Kalyani, Kalyani 741 235, India. ∗. Corresponding author. E-mail: nanda.ku@rediffmail.com. MS received 26 November 2010; revised 30 July 2011; ...
Stability of Coulomb crystals in a linear Paul trap with storage-ring-like confinement
DEFF Research Database (Denmark)
Kjærgaard, Niels; Mølhave, Kristian; Drewsen, Michael
2002-01-01
We report experiments on the stability of ion Coulomb crystals in a linear Paul trap with storage-ring-like confinement. The transverse dynamics of charged particles in a trap of this type is analogous to that of a fast beam traveling through a channel with periodic, magnetic alternating gradient...
Spatial mode effects in a cavity-EIT based quantum memory with ion Coulomb crystals
DEFF Research Database (Denmark)
Zangenberg, Kasper Rothe; Dantan, Aurelien Romain; Drewsen, Michael
2012-01-01
Quantum storage and retrieval of light in ion Coulomb crystals using cavity electromagnetically induced transparency are investigated theoretically. It is found that when both the control and the probe fields are coupled to the same spatial cavity mode, their transverse mode profile affects...
Accurate Coulomb Potentials for Periodic and Molecular Systems through Density Fitting
Franchini, M.; Philipsen, P.H.T.; van Lenthe, E.; Visscher, L.
2014-01-01
We present a systematically improvable density fitting scheme designed for accurate Coulomb potential evaluation of periodic and molecular systems. The method does not depend on the way the density is calculated, allowing for a basis set expansion as well as a numerical representations of the
Probing single-particle and collective states in atomic nuclei with Coulomb excitation
DiJulio, Douglas
A series of experiments and developments, related to stable and radioactive isotopes, have been carried out. These studies have focused on measuring the low-lying excitations of spherical and deformed nuclei using electromagnetic (Coulomb) excitation and also on developments in detector technology for upcoming radioactive ion beams facilities. The low-lying excitations in the nuclei 107,109Sn and 107In have been investigated using low-energy Coulomb excitation at the REX-ISOLDE facility at CERN. The measured reduced transition probabilities were compared to predictions of nuclear structure models. In addition, a relativistic Coulomb excitation experiment was carried out using the FRS at GSI with the nucleus 104Sn. These radioactive ion beam experiments provide important constraints for large-scale-shell-model calculations in the region of the doubly magic nucleus 100Sn. A stable Coulomb excitation experiment was also carried out in order to explore the properties of low-lying structures in the nucleus 170Er...
Splitting of Potential Curves in the Two-Coulomb-Centre Problem
Hnatič, Michal; Khmara, Viktor M.; Lazur, Volodymyr Yu.; Reity, Oleksandr K.
2018-02-01
The quasiclassical expression for the exchange interaction ΔE of potential curves at the points of their quasicrossing in the two-Coulomb-centre problem is found. It can be used for the calculation of cross sections of charge exchange processes between hydrogen or hydrogen-like atoms and bare nuclei.
Assessment of Coulomb shifts in nucleon scattering resonances on light nuclei at low energies
International Nuclear Information System (INIS)
Takibaev, N.Zh.; Uzakova, Zh.; Abdanova, L.
2003-01-01
The assessments of the Coulomb forces contribution to position and width of the resonances at nucleons scattering on light nuclei within low energy field are given. In particular the shifts of resonances in amplitudes arising in the processes protons scattering on light nuclei relatively neutrons scattering resonance characteristics on these nuclei are considered
Screening of Coulomb interaction and many-body perturbation theory in atoms
International Nuclear Information System (INIS)
Dzyuba, V.A.; Flambaum, V.V.; Sil'vestrov, P.G.; Sushkov, O.P.
1988-01-01
Taking into account the electron Coulomb interaction screening considerably improves the convergence of perturbation theory in residual interaction. The developed technique allows to take into account screening diagrams in all orders of perturbation theory. Calculation of the correlation corrections to the thallium energy levels is carried out as an example
Dynamics of Braking Vehicles: From Coulomb Friction to Anti-Lock Braking Systems
Tavares, J. M.
2009-01-01
The dynamics of braking of wheeled vehicles is studied using the Coulomb approximation for the friction between road and wheels. The dependence of the stopping distance on the mass of the vehicle, on the number of its wheels and on the intensity of the braking torque is established. It is shown that there are two regimes of braking, with and…
Thermoelectrics in Coulomb-coupled quantum dots: Cotunneling and energy-dependent lead couplings
DEFF Research Database (Denmark)
Walldorf, Nicklas; Jauho, Antti-Pekka; Kaasbjerg, Kristen
2017-01-01
We study thermoelectric effects in Coulomb-coupled quantum-dot (CCQD) systems beyond lowest-order tunneling processes and the often applied wide-band approximation. To this end, we present a master-equation (ME) approach based on a perturbative T -matrix calculation of the charge and heat tunneling...
The pushing gate in a planar Coulomb crystal using a flat-top laser beam
Energy Technology Data Exchange (ETDEWEB)
Kitaoka, M., E-mail: kitaoka@lyman.q.t.u-tokyo.ac.j [Department of Systems Innovation, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Buluta, I.M. [Department of Quantum Engineering and Systems Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Hasegawa, S., E-mail: hasegawa@sys.t.u-tokyo.ac.j [Department of Systems Innovation, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Department of Quantum Engineering and Systems Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan)
2009-08-10
We propose a pushing gate for entangling two ions in a planar Coulomb crystal in the view of realizing large-scale quantum simulations. A tightly focused laser is irradiated from the direction perpendicular to the crystal plane and its spatial intensity profile generates a state-dependent force. We analyze the error sources in this scheme and obtain low infidelity.
The pushing gate in a planar Coulomb crystal using a flat-top laser beam
Kitaoka, M.; Buluta, I. M.; Hasegawa, S.
2009-08-01
We propose a pushing gate for entangling two ions in a planar Coulomb crystal in the view of realizing large-scale quantum simulations. A tightly focused laser is irradiated from the direction perpendicular to the crystal plane and its spatial intensity profile generates a state-dependent force. We analyze the error sources in this scheme and obtain low infidelity.
Coulomb correction to the screening angle of the Moliere multiple scattering theory
International Nuclear Information System (INIS)
Kuraev, E.A.; Voskresenskaya, O.O.; Tarasov, A.V.
2012-01-01
Coulomb correction to the screening angular parameter of the Moliere multiple scattering theory is found. Numerical calculations are presented in the range of nuclear charge 4 ≤ Z ≤ 82. Comparison with the Moliere result for the screening angle reveals up to 30% deviation from it for sufficiently heavy elements of the target material
Observation of a structural transition for coulomb crystals in a linear Paul trap
DEFF Research Database (Denmark)
Kjærgaard, N.; Drewsen, M.
2003-01-01
A structural transition for laser cooled ion Coulomb crystals in a linear Paul trap just above the stability limit of parametrically resonant excitation of bulk plasma modes has been observed. In contrast to the usual spheroidal shell structures present below the stability limit, the ions arrange...
Coulomb drag in anisotropic systems: a theoretical study on a double-layer phosphorene
Saberi-Pouya, S.; Vazifehshenas, T.; Farmanbar Gelepordsari, M.; Salavati-Fard, T.
2016-01-01
We theoretically study the Coulomb drag resistivity in a double-layer electron system with highly anisotropic parabolic band structure using Boltzmann transport theory. As an example, we consider a double-layer phosphorene on which we apply our formalism. This approach, in principle, can be tuned
Non conventional screening of the Coulomb interaction in C-60 and in carbon nanotubes
van den Brink, J; Sawatzky, GA; Kuzmany, H; Fink, J; Mehring, M; Roth, S
1998-01-01
We study the screening of the Coulomb interaction in C-60 and carbon nanotubes. It is shown that for these systems the screening deviates strongly from the Clausius-Mossotti behavior. The short range interaction is strongly screened and the long range interaction is anti-screened, thereby strongly
Can Coulomb Sturmians Be Used as a Basis for N-Electron Molecular Calculations?
DEFF Research Database (Denmark)
Avery, John Scales; Avery, James Emil
2009-01-01
A method is proposed for using isoenergetic configurations formed from many-center Coulomb Sturmians as a basis for calculations on N-electron molecules. Such configurations are solutions to an approximate N-electron Schrödinger equation with a weighted potential, and they are thus closely analog...
International Nuclear Information System (INIS)
Zaytsev, S A
2010-01-01
The possibility of using straight-line paths of integration in computing the integral representation of the three-body Coulomb Green's function is discussed. In our numerical examples two different kinds of integration contours in the complex energy planes are considered. It is demonstrated that straight-line paths, which cross the positive real axis, are suitable for numerical computation.
Solvability of Static Contact Problems with Coulomb Friction for Orthotropic Material
Czech Academy of Sciences Publication Activity Database
Eck, C.; Jarušek, Jiří
2008-01-01
Roč. 93, č. 1 (2008), s. 93-104 ISSN 0374-3535 R&D Projects: GA AV ČR IAA1075402 Institutional research plan: CEZ:AV0Z10190503 Keywords : contact problem * Coulomb friction * orthotropic elasticity Subject RIV: BA - General Mathematics Impact factor: 1.277, year: 2008
Proton optical potential and scattering matrix for tin nuclei at sub-coulomb energies
International Nuclear Information System (INIS)
Guzhovskij, B.Ya.; Dzyuba, B.M.
1981-01-01
A unified set of parameters of the proton optical potential (OP) for the n nuclei is searched for in the below-Coulomb-barrier energy range. The set must describe well the experimental data on the pn-reaction total cross sections and on the angular distributions of elastically scattered protons at E [ru
On the integral representations of the Jost function and Coulomb off ...
Indian Academy of Sciences (India)
Abstract. The integral representations of the Jost function (on- and off-shell) are red- erived by the judicious use of the transposed operator relation on the particular integrals for Jost solution and using one of these particular integrals an analytical expression for the Coulomb off-shell Jost solution is presented in the maximal ...
Dissociation of deuteron, 6He and 11Be from Coulomb dissociation ...
Indian Academy of Sciences (India)
Home; Journals; Pramana – Journal of Physics; Volume 70; Issue 5. Dissociation of ... Diffraction dissociation; Coulomb effect; post-acceleration phenomenon; momentum distribution; bremsstrahlung integral; halo structure. ... Physics Department, Vivekananda College, 269, Diamond Harvour Road, Kolkata 700 063, India ...
Linear-response theory of Coulomb drag in coupled electron systems
DEFF Research Database (Denmark)
Flensberg, Karsten; Hu, Ben Yu-Kuang; Jauho, Antti-Pekka
1995-01-01
We report a fully microscopic theory for the transconductivity, or, equivalently, the momentum transfer rate, of Coulomb coupled electron systems. We use the Kubo linear-response formalism and our main formal result expresses the transconductivity in terms of two fluctuation diagrams, which...
Dissociation of deuteron, 6He and 11Be from Coulomb dissociation ...
Indian Academy of Sciences (India)
Abstract. The fragmentation of deuteron, 6He and 11Be have been studied during in- teraction with the 208Pb nucleus at various projectile energies. The Coulomb dissocia- tion cross-sections and the momentum distribution of the break-up fragments have been analysed within the framework of the direct fragmentation ...
Coulomb explosion during the early stages of the reaction of alkali metals with water
Czech Academy of Sciences Publication Activity Database
Mason, Philip E.; Uhlig, Frank; Vaněk, Václav; Buttersack, T.; Bauerecker, S.; Jungwirth, Pavel
2015-01-01
Roč. 7, č. 3 (2015), s. 250-254 ISSN 1755-4330 R&D Projects: GA ČR GBP208/12/G016 Institutional support: RVO:61388963 Keywords : sodium-potasium alloy * water * coulomb explosion * high-speed camera * molecular dynamics Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 27.893, year: 2015
A quark model for nuclear matter and the Coulomb sum rule
International Nuclear Information System (INIS)
Horowitz, C.J.; Massachusetts Inst. of Tech., Cambridge
1985-01-01
The quark correlation function g(r), of nuclear matter is calculated in a simple model with many of the essential composite features of nucleons. From g the Coulomb sum rule is calculated and found not to go to unity because there is substantial overlap of momentum scales describing NN correlations and nucleon substructure. (orig.)
Palatnik, Dmitriy
2002-01-01
In this note one suggests a possibility of direct observation of the $\\theta$-parameter, introduced in the Born--Infeld theory of electroweak and gravitational fields, developed in quant-ph/0202024. Namely, one may treat $\\theta$ as a universal constant, responsible for correction to the Coulomb and Newton laws, allowing direct interaction between electrical charges and masses.
The European Food Consumption Validation Project: conclusions and recommendations
DEFF Research Database (Denmark)
de Boer, E. J.; Slimani, N.; van 't Veer, P.
2011-01-01
Background/Objectives: To outline and discuss the main results and conclusions of the European Food Consumption Validation (EFCOVAL) Project. Subjects/Methods: The EFCOVAL Project was carried out within the EU Sixth Framework Program by researchers in 11 EU countries. The activities focused on (1......) the further development of the EPIC-Soft software (the software developed to conduct 24-h dietary recalls (24-HDRs) in the European Prospective Investigation into Cancer and Nutrition (EPIC) Study) and the validation of the 2-day non-consecutive 24-HDR method using EPIC-Soft, (2) defining and investigating...... showed that two non-consecutive EPIC-Soft 24-HDRs are suitable to estimate the usual intake distributions of protein and potassium of European adult populations. The 2-day non-consecutive 24-HDRs in combination with a food propensity questionnaire also appeared to be appropriate to rank individuals...
Snakebites in French Guiana: Conclusions of an international symposium.
Kallel, Hatem; Hommel, Didier; Mehdaoui, Hossein; Megarbane, Bruno; Resiere, Dabor
2018-05-01
A workshop on epidemiology and management of snakebites in French Guiana was performed at Cayenne, French Guiana from September 15 to September 16, 2017, under the auspices of the French Regional Health Agency (ARS) and the Pan American Health Organization (PAHO). The activity was attended by experts from France (Angers, Martinique, French Guiana, Guadeloupe, and Paris), Costa Rica, Brazil, Saint Lucia, and Surinam. The epidemiology, clinical manifestations, clinical grading and the management of snakebite in French Guiana were discussed. The conclusions of this symposium illustrated the urgent need to ensure accessibility of effective and safe polyvalent viperid antivenom in French Guiana. Finally, the results of this symposium have forged ties based on mutual goals and objectives. Copyright © 2018 Elsevier Ltd. All rights reserved.
Leaping to Conclusions: Why Premise Relevance Affects Argument Strength.
Ransom, Keith J; Perfors, Amy; Navarro, Daniel J
2016-09-01
Everyday reasoning requires more evidence than raw data alone can provide. We explore the idea that people can go beyond this data by reasoning about how the data was sampled. This idea is investigated through an examination of premise non-monotonicity, in which adding premises to a category-based argument weakens rather than strengthens it. Relevance theories explain this phenomenon in terms of people's sensitivity to the relationships among premise items. We show that a Bayesian model of category-based induction taking premise sampling assumptions and category similarity into account complements such theories and yields two important predictions: First, that sensitivity to premise relationships can be violated by inducing a weak sampling assumption; and second, that premise monotonicity should be restored as a result. We test these predictions with an experiment that manipulates people's assumptions in this regard, showing that people draw qualitatively different conclusions in each case. Copyright © 2015 Cognitive Science Society, Inc.
Conclusion of the I.C.T. benchmark exercise
International Nuclear Information System (INIS)
Giacometti, A.
1991-01-01
The ICT Benchmark exercise made within the RIV working group of ESARDA on reprocessing data supplied by COGEMA for 53 routines reprocessing input batches made of 110 irradiated fuel assemblies from KWO Nuclear Power Plant was finally evaluated. The conclusions are: all seven different ICT methods applied verified the operator data on plutonium within about one percent; anomalies intentionally introduced to the operator data were detected in 90% of the cases; the nature of the introduced anomalies, which were unknown to the participants, was completely resolved for the safeguards relevant cases; the false alarm rate was in a few percent range. The ICT Benchmark results shows that this technique is capable of detecting and resolving anomalies in the reprocessing input data to the order of a percent
Evidence-based therapy relationships: research conclusions and clinical practices.
Norcross, John C; Wampold, Bruce E
2011-03-01
In this closing article of the special issue, we present the conclusions and recommendations of the interdivisional task force on evidence-based therapy relationships. The work was based on a series of meta-analyses conducted on the effectiveness of various relationship elements and methods of treatment adaptation. A panel of experts concluded that several relationship elements were demonstrably effective (alliance in individual psychotherapy, alliance in youth psychotherapy, alliance in family therapy, cohesion in group therapy, empathy, collecting client feedback) while others were probably effective (goal consensus, collaboration, positive regard). Three other relationship elements (congruence/genuineness, repairing alliance ruptures, and managing countertransference) were deemed promising but had insufficient evidence to conclude that they were effective. Multiple recommendations for practice, training, research, and policy are advanced. (PsycINFO Database Record (c) 2011 APA, all rights reserved).
Dynamics of fission and Coulomb explosion of multicharged large finite systems
Levy, Y.; Last, I.; Jortner, J.
This paper reports on studies of the fragmentation dynamics of multicharged (A+)55 Morse clusters, where the variation of the range of the Morse potential parameters induces cluster fission for a long-range potential and Coulomb explosion for a short-range potential. The multidimensional energy landscapes for these fragmentation processes were explored by constructing reduced coordinates utilizing the principal component analysis (PCA), which was previously applied for the energy landscapes and folding dynamics of biomolecules. The distance-matrix based PCA was applied to study the effects of the potential on the fragmentation dynamics and to explore the structural diversity of the fragmentation processes. The first principal coordinate (which captures 95% of the dynamic information content for each trajectory) constitutes an appropriate reaction coordinate for both fission and Coulomb explosion and was used to determine the temperature-dependent fragmentation rates. These obey the Arrhenius law, with the barrier for fission (0.36 eV) being higher than for Coulomb explosion (0.22 eV). Structural and energetic information on the radius of gyration and on the potential energy for small values of the reaction coordinate manifest considerably larger fluctuations for fission than for Coulomb explosion, indicating that in the former case the cluster shrinks and swells prior to dissociation. The joint projection of multiple trajectories for each fragmentation process allows for the description of the energy landscapes and fragmentation pathways in terms of two principal coordinates, which manifest a form of 'ski slopes'. Different collective coordinates describe the spatially isotropic Coulomb explosion and the spatially unisotropic fission.
Bionics in Engineering Education Considerations, Experiences and Conclusions
Directory of Open Access Journals (Sweden)
Ralf Neurohr
2008-01-01
Full Text Available During recent years bionics, a new discipline which is in charge with the transfer of the principles of construction, regulation, interaction and organisation of biology into innovative technical solutions, has attracted significant interest from various industries. Based on this request for bionic expertise in engineering, the faculty for teaching engineering in foreign languages (FILS at ‘Politehnica’ University of Bucharest started a course in bionics in SS 2007, which was supported by the expertise of the German ‘Bionik-Kompetenz-Netz’, one of the leading organizations in bionics. This is the report on the considerations involved in the course concept, the first experiences with the students' acceptance, some conclusions and future perspectives for extending bionics activities at ‘Politehnica’. Finally, within the last section, the evaluation of a questionnaire, filled in by the students at the end of the course, will be presented. In order to avoid any confusion, considering overlapping or mixing up with other bio-disciplines related to technology, the paper starts with a short introduction, explaining the principles of bionics and providing a clear definition of the field.
Waste dislodging and conveyance testing summary and conclusions to date
International Nuclear Information System (INIS)
Rinker, M.W.; Hatchell, B.K.; Mullen, O.D.
1994-09-01
This document summarizes recent work performed by the Waste Dislodging and Conveyance technology development program to provide assistance with the retrieval of wastes from the Hanford single-shell tanks (SSTs). This work is sponsored by the Underground Storage Tank-Integrated Demonstration (UST-ID) Office with the U.S. Department of Energy (DOE) Office of Technology Development. A baseline technology of high-pressure water-jet dislodging and pneumatic conveyance integrated as a scarifier is proposed as a means of retrieval. The tests and studies described were performed to demonstrate that at least one robust technology exists that could be effectively used with low water-addition arm-based systems. These results are preliminary and do not represent an optimized baseline. The Waste Dislodging and Conveyance work thus far has demonstrated that waterjet mobilization and air conveyance can mobilize and convey SST waste simulants at the target rates while operating within the space envelope and the dynamic loading constraints of deployment devices. The recommended technologies are well proven in industrial applications and are quite robust, yet lightweight and relatively benign to the retrieval environment. The baseline approach has versatility to continuously dislodge and convey a broad range of waste forms, from hard wastes to soft sludge wastes. The approach also has the major advantage of being noncontact with the waste surface under normal operation
Coulomb problem on single- and double-wall cylinders
International Nuclear Information System (INIS)
Deinega, Alexei; Voronova, Nina; Lozovik, Yurii
2012-01-01
In this paper we calculate the energies of ground and excited states of two opposite charge carriers confined on a single- or double-wall cylindrical surface. A nontrivial dependence of excited state energies on cylinder radius value (for the case of a single-wall cylinder) is found, and the explanation of this behavior is based on symmetry properties of the corresponding wavefunctions. The crossover from a one-dimensional problem to a two-dimensional one with increase of the radius value is discussed in detail. For the double-wall cylinder, we obtain and analyze the dependence of ground state energy on interwall distance and ratio between particle masses. (paper)
The Danish energy crop research and development project - main conclusions
International Nuclear Information System (INIS)
Gylling, Morten
2003-01-01
Production of energy crops in Denmark is more or less non-existent in Denmark at the time being. However, the need for biomass on the other side of year 2005 exceeds the existing biomass resources and a substantial amount of energy crops will be necessary in order to fulfil the goals in Energy 21. The targeted share of the use of renewable energy sources by year 2030 is approximately 30%. Energy crops are seen as the most important new resource in order to create a balanced input mix of renewable in the energy system. The energy crops are mainly seen as fuel in small and medium sized CHP plants and in the big power plants. The Danish energy crop project consists of three main parts: a demonstration part, a research and development part, and an overall assessment part. Based on the results from the project the following overall conclusions can be made: Seen from a strictly market and production economic point of view energy crops will not be competitive in a foreseeable future, neither as a production for farmers nor as a fuel at the utility companies; The costs per GJ of energy crops are still higher than a GJ of straw; The cost difference between annual and perennial energy crops are slightly in favour of perennials, however the conditions on the individual farms should govern the choice between annual and perennial energy crops; Energy crops must be seen as part of an overall environmental scheme covering both agriculture and the energy sector; Given the right production scheme energy crops can be grown on environmental sensitive areas and on most ground water protection areas; Adding the potential sustainability benefits like reduced nutrient leakage and reduced CO 2 emissions energy crops seem to be a sensible and sustainable solution; Due to different handling, storage and fuel characteristics an all year delivery scheme of energy crops should include a mix of different energy crops to keep overall cost down. (BA)
International Nuclear Information System (INIS)
Wegner, H.E.; Thieberger, P.
1984-01-01
The charge state of fast C + ions is assumed to reach some equilibrium value within a few atomic layers after entering a thin carbon stripping foil and then maintain that average charge state while passing through the rest of the foil. The final distribution of different charge states is then assumed to occur at or near the exit surface of the foil by various pickup and stripping processes. Experimentally, the final charge state distribution is easily measured; however, the average charge state inside the foil is difficult to measure in any direct way. This paper describes the experimental method and results of measuring this internal average charge state for 3.5 MeV carbon ions by utilizing the Coulomb explosion of 7 MeV C 2 + molecular ions. The interesting result is that the internal average charge state is 4.2+-x, and the final charge state distribution is not established at the exit surface of the foil, but beyond, approximately 100 A, a distance comparable to the foil thickness in this measurement
International Nuclear Information System (INIS)
Wegner, H.E.; Thieberger, P.
1986-01-01
The charge state of fast C + ions is assumed to reach some equilibrium value within a few atomic layers after entering a thin carbon stripping foil and then maintain that average charge state while passing through the rest of the foil. The final distribution of different charge states is then assumed to occur at or near the exist surface of the foil by various pickup and stripping processes. Experimentally, the final charge state distribution is easily measured; however, the average charge state inside the foil is difficult to measure in any direct way. This paper describes the experimental method and results of measuring this internal average charge state for 3.5 MeV carbon ions by utilizing the Coulomb explosion of 7 MeV C 2 + molecular ions. The interesting result is that the internal average charge state is 4.2 +/- x, and the final charge state distribution is not established at the exit surface of the foil, but beyond, approximately 100 a, a distance comparable to the foil thickness in this measurement. 1 reference, 6 figures
Implementation of severe accident management measures - Summary and conclusions
International Nuclear Information System (INIS)
2002-01-01
implemented in various ways in many plants, but not yet in all plants. A systematic approach, which is based upon a clearly defined decision-making process, is one of the features implemented in many cases. Available means are determined and priorities are set. This approach is made up of strategies intended to become an optimum approach to prevent or mitigate the consequences of beyond-design basis accidents. It is based upon a prepared information package about plant-specific behaviour to be expected in beyond design scenarios. The approaches followed in the different countries do not fit one single pattern. Harmonization, to the extent it is desirable, does not seem feasible at this stage. As a rule, the responsibility of the plant owner for the safety of his plant remains untouched. Also, safety goals may vary between countries. This report presents the general conclusion and recommendations of the workshop and the summaries of the sessions
International Nuclear Information System (INIS)
Fan, J.D.; Malozovsky, Y.M.
2013-01-01
Highlights: • In a layered 2D cuprates the long-range order antiferromagnetism is driven mainly by the Van Hove singularity. • The long-range antiferromagnetism quickly disappear with doping away from the Van Hove singularity. • For pnictides the antiferromagnetism exists as a result of the nesting condition. • Since the doping steadily changes the nesting conditions, the antiferromagnetism and superconductivity may coexist. -- Abstract: We consider the Hubbard model in terms of the perturbative diagrammatic approach (UN F ⩽1) where the interaction between two electrons with antiparallel spins in the lowest order of perturbation is described by the short-range repulsive contact (on-site) interaction (U>0). We argue that in layered 2D cuprates the long-range order antiferromagnetism is driven mainly by the Van Hove singularity, whereas in the case of pnictides the antiferromagnetism exists as a result of the nesting condition. We show that when the interaction is quite strong (UN F ≈1) in the case of the Van Hove singularity the electron system undergoes the antiferromagnetic phase transition with the log-range order parameter and large insulating gap. The long-range antiferromagnetism quickly disappear, as shown, with the doping away from the Van Hove singularity, but the antiferromagnetic short-range correlation persists (UN F < 1) due to Coulomb repulsive interaction which is the mechanism for superconductivity in cuprates. We argue that in the case of pnictides the antiferromagnetism appears when the nesting conditions for the Fermi surface are met. Since the doping steadily changes the nesting conditions, the antiferromagnetism and superconductivity may coexist as has been observed in pnictides. We show that the proximity of the antiferromagnetism and superconductivity implies the repulsive interaction between electrons, which turns into attractive between quasiparticles as shown by the authors in the article published on the same issue as this one
CSNI/NEA Rasplav seminar 2000. Summary and conclusions
International Nuclear Information System (INIS)
2001-01-01
various boundary conditions were investigated. The work involved a combination of integral and separate effect tests including molten-salt tests to investigate non-eutectic mixtures and the effects of stratification, extension of the material property database to allow interpretation and modelling of the experimental data. The CSNI decided to hold a seminar where the major outcome of the RASPLAV Project could be presented and discussed also in the context of other experienced activities on Severe Accidents. The objectives of the seminar are: - to review the experimental results of the RASPLAV Project; - to exchange information on complementary research; - to discuss the progress made on understanding severe accident progression; - to discuss the applicability to nuclear power plants and use of the results. The Seminar was intended to provide an in-depth review of the RASPLAV Project in terms of the technical capabilities, results and analyses produced during the project execution. The application of the results and their significance for power plant applications were addressed. Relevant results of the complementary research carried out at various laboratories were also presented. The seminar consisted of five sessions organised as follows: - Opening and overview; - Experimental results; - Theoretical Analyses; - Application and complementary research; - Conclusion
Northern Canada in a Changing Climate: Major Findings and Conclusions
Energy Technology Data Exchange (ETDEWEB)
Prowse, Terry D.; Peters, Daniel L. (Water and Climate Impacts Research Centre, Environment Canada, Dept. of Geography, Univ. of Victoria, Victoria, BC (Canada)). e-mail: terry.prowse@ec.gc.caa; Furgal, Chris (Indigenous Environmental Studies Program, Trent Univ., Peterborough, ON (Canada))
2009-07-15
Key findings include: Climate-induced changes in the cryosphere have large implications for infrastructure maintenance and design. Much of the infra-structure in the North is dependent upon the cryosphere to, for example, provide stable surfaces for buildings and pipelines, contain wastes, stabilize shorelines, and provide access to remote communities in the winter. Permafrost warming and thaw may require remedial action or further engineering modifications to existing infrastructure. Waste retention ponds and lakes that rely on the impervious nature of permafrost to retain environmentally hazardous materials are a particular concern. In the longer term, marine and freshwater transportation will need to shift its reliance from ice routes to open-water or land-based transport systems. Coastal areas and communities will also become more vulnerable to erosion with loss of sea ice compounded with increased storminess and rising sea levels. Changes in the timing of river flows will require modifications to the infrastructure and flow strategies used in generating hydroelectricity. As the climate continues to change, there will be consequences for biodiversity shifts and in ranges and distribution of many species with impacts on availability, accessibility, and quality of resources upon which human populations rely. The northward migration of species, and disruption and competition from invading species, are already occurring and will continue to alter terrestrial and aquatic communities. Shifting environmental conditions will likely introduce new animal transmitted diseases and redistribute some existing diseases, affecting key economic resources and some human populations. Stress on populations of iconic wildlife species will likely continue as a result of changes to critical sea-ice habitat. Where these stresses affect economically or culturally important species, they will have significant impacts on people and regional economies. Increased navigability of Arctic
International Nuclear Information System (INIS)
Ng, Kong Soon; Moo, Chin-Sien; Chen, Yi-Ping; Hsieh, Yao-Ching
2009-01-01
The coulomb counting method is expedient for state-of-charge (SOC) estimation of lithium-ion batteries with high charging and discharging efficiencies. The charging and discharging characteristics are investigated and reveal that the coulomb counting method is convenient and accurate for estimating the SOC of lithium-ion batteries. A smart estimation method based on coulomb counting is proposed to improve the estimation accuracy. The corrections are made by considering the charging and operating efficiencies. Furthermore, the state-of-health (SOH) is evaluated by the maximum releasable capacity. Through the experiments that emulate practical operations, the SOC estimation method is verified to demonstrate the effectiveness and accuracy.
Temperature dependence of Coulomb oscillations in a few-layer two-dimensional WS2 quantum dot
Song, Xiang-Xiang; Zhang, Zhuo-Zhi; You, Jie; Liu, Di; Li, Hai-Ou; Cao, Gang; Xiao, Ming; Guo, Guo-Ping
2015-11-01
Standard semiconductor fabrication techniques are used to fabricate a quantum dot (QD) made of WS2, where Coulomb oscillations were found. The full-width-at-half-maximum of the Coulomb peaks increases linearly with temperature while the height of the peaks remains almost independent of temperature, which is consistent with standard semiconductor QD theory. Unlike graphene etched QDs, where Coulomb peaks belonging to the same QD can have different temperature dependences, these results indicate the absence of the disordered confining potential. This difference in the potential-forming mechanism between graphene etched QDs and WS2 QDs may be the reason for the larger potential fluctuation found in graphene QDs.
The coulomb dissociation of 8B and implications for the S17 astrophysical S-Factor
International Nuclear Information System (INIS)
Boue, Frederic
1999-01-01
The interpretation of the solar neutrino flux observed on Earth compared to the predicted one depends on the cross section of the 7 Be(p,γ) 8 B reaction (or equivalently on the Sn-factor) which has a rather large uncertainty (>20%) and has to be re-measured. The Coulomb dissociation of 8 B is an alternative method to measure the S 17 -factor. We performed at GSI an experiment using a secondary radioactive beam of 8 B at E( 8 B) = 254 A.MeV and the large acceptance spectrometer KaoS. Using an identification event by event and invariant-mass analysis, the differential Coulomb-dissociation cross section as a function the relative energy between fragments is deduced. Using the theorem of detailed balance, the S 17 -factor is extracted. With the help of theoretical descriptions, the measured data are extrapolated to solar energies. (author) [fr
Anomalous low-temperature Coulomb drag in graphene-GaAs heterostructures.
Gamucci, A; Spirito, D; Carrega, M; Karmakar, B; Lombardo, A; Bruna, M; Pfeiffer, L N; West, K W; Ferrari, A C; Polini, M; Pellegrini, V
2014-12-19
Vertical heterostructures combining different layered materials offer novel opportunities for applications and fundamental studies. Here we report a new class of heterostructures comprising a single-layer (or bilayer) graphene in close proximity to a quantum well created in GaAs and supporting a high-mobility two-dimensional electron gas. In our devices, graphene is naturally hole-doped, thereby allowing for the investigation of electron-hole interactions. We focus on the Coulomb drag transport measurements, which are sensitive to many-body effects, and find that the Coulomb drag resistivity significantly increases for temperatures law, therefore displaying a notable departure from the ordinary quadratic temperature dependence expected in a weakly correlated Fermi-liquid. This anomalous behaviour is consistent with the onset of strong interlayer correlations. Our heterostructures represent a new platform for the creation of coherent circuits and topologically protected quantum bits.
Probing core polarization around 78Ni: intermediate energy Coulomb excitation of 74Ni
Directory of Open Access Journals (Sweden)
Marchi T.
2013-12-01
We have recently measured the B(E2; 0+ → 2+ of the 74Ni nucleus in an intermediate-energy Coulomb excitation experiment performed at the National Superconducting Cyclotron Laboratory of the Michigan State University. The 74Ni secondary beam has been produced by fragmentation of 86Kr at 140 AMeV on a thick Be target. Selected radioactive fragments impinged on a secondary 197Au target where the measurement of the emitted γ-rays allows to extract the Coulomb excitation cross section and related structure information. Preliminary B(E2 values do not point towards an enhancement of the transition matrix element and the comparison to what was already measured by Aoi and co-workers in [1] opens new scenarios in the interpretation of the shell evolution of the Z=28 isotopes.
Direct and resonant breakup of {sup 6}He on {sup 209}Bi near the Coulomb barrier
Energy Technology Data Exchange (ETDEWEB)
Kolata, J.J. [Physics Department, University of Notre Dame, Notre Dame, Indiana, 46556-5670 (United States)
2007-12-15
As part of a program to study reactions induced by the two-neutron halo nucleus {sup 6}He on high-Z targets, a neutron-{alpha} particle coincidence experiment was performed for {sup 6}He incident on a {sup 209}Bi target at an energy just above the Coulomb barrier. The experimental setup was optimized for the measurement of projectile breakup. Direct breakup, as well as breakup through the 2{sup +} excited state of {sup 6}He and also the {sup 5}He+n channel, could be distinguished. The total breakup cross section measured in this work compares well with a continuum-discretized coupled-channels calculation that assumes a 50% reduction in the B(E1) computed from a pure {sup 4}He+2n cluster configuration. The B(E2{up_arrow}) for Coulomb excitation of the 2{sup +} state in {sup 6}He was also determined. (Author)
Effect of Coulomb correlation on charge transport in disordered organic semiconductors
Liu, Feilong; van Eersel, Harm; Xu, Bojian; Wilbers, Janine G. E.; de Jong, Michel P.; van der Wiel, Wilfred G.; Bobbert, Peter A.; Coehoorn, Reinder
2017-11-01
Charge transport in disordered organic semiconductors, which is governed by incoherent hopping between localized molecular states, is frequently studied using a mean-field approach. However, such an approach only considers the time-averaged occupation of sites and neglects the correlation effect resulting from the Coulomb interaction between charge carriers. Here, we study the charge transport in unipolar organic devices using kinetic Monte Carlo simulations and show that the effect of Coulomb correlation is already important when the charge-carrier concentration is above 10-3 per molecular site and the electric field is smaller than 108 V/m. The mean-field approach is then no longer valid, and neglecting the effect can result in significant errors in device modeling. This finding is supported by experimental current density-voltage characteristics of ultrathin sandwich-type unipolar poly(3-hexylthiophene) (P3HT) devices, where high carrier concentrations are reached.
Energy Technology Data Exchange (ETDEWEB)
Hellgartner, Stefanie Christine
2015-11-13
In this work, the N=40 subshell closure is investigated with two complementary methods using a radioactive {sup 72}Zn ISOLDE beam: One- and two-neutron transfer reactions and multiple Coulomb excitation. In the one-neutron transfer reaction, two new levels of {sup 73}Zn were discovered. The two-neutron transfer channel allowed to study the differential cross section of the ground state and the 2{sup +}{sub 1} state of {sup 74}Zn. In the Coulomb excitation experiment, the measured B(E2) values and quadrupole moments of {sup 72}Zn showed that the yrast states 0{sup +}{sub 1}, 2{sup +}{sub 1} and 4{sup +}{sub 1} are moderately collective. Contrary, the 0{sup +}{sub 2} state has a different structure, since it features a stronger closed N=40 configuration compared to the ground state.
Study of the neutron rich sulfure isotope 43S through intermediate energy Coulomb excitation
Calinescu, S.; Cáceres, L.; Grévy, S.; Sohler, D.; Stanoiu, M.; Negoita, F.; Borcea, C.; Borcea, R.; Bowry, M.; Catford, W.; Dombradi, Z.; Franchoo, S.; Gillibert, R.; Thomas, J. C.; Kuti, I.; Lukyanov, S.; Lepailleur, A.; Mrazek, J.; Niikura, M.; Podolyak, Z.; Petrone, C.; Penionzhkevich, Y.; Roger, T.; Rotaru, F.; Sorlin, O.; Stefan, I.; Vajta, Z.; Wilson, E.
2013-02-01
The reduced transition probability B(E2: 3/2- 7/2-2) has been measured in 43S using Coulomb excitation at intermediate energy. The nucleus of interest was produced by fragmentation of a 48Ca beam at GANIL. The reaction products were separated in the LISE spectrometer. After Coulomb-excitation of 43S in a 208Pb target, the γ rays emitted inflight were detected by 64 BaF2 detectors of the Chǎteau de Cristal array. The preliminary value deduced for the reduced transition probability B(E2: 3/2-7/2-2) is in agreement with the predictions of the shell model calculations and supports a prolate-spherical shape coexistence in the 43S nucleus.
Onset of Coulomb explosion in small silicon clusters exposed to strong-field laser pulses
Sayres, S. G.; Ross, M. W.; Castleman, A. W., Jr.
2012-05-01
It is now well established that, under intense laser illumination, clusters undergo enhanced ionization compared to their isolated atomic and molecular counterparts being subjected to the same pulses. This leads to extremely high charge states and concomitant Coulomb explosion. Until now, the cluster size necessary for ionization enhancement has not been quantified. Here, we demonstrate that through the comparison of ion signal from small covalently bound silicon clusters exposed to low intensity laser pulses with semi-classical theory, their ionization potentials (IPs) can be determined. At moderate laser intensities the clusters are not only atomized, but all valence electrons are removed from the cluster, thereby producing up to Si4+. The effective IPs for the production of the high charge states are shown to be ˜40% lower than the expected values for atomic silicon. Finally, the minimum cluster size responsible for the onset of the enhanced ionization is determined utilizing the magnitude of the kinetic energy released from the Coulomb explosion.
Perturbed Coulomb Potentials in the Klein-Gordon Equation: Quasi-Exact Solution
Baradaran, M.; Panahi, H.
2018-05-01
Using the Lie algebraic approach, we present the quasi-exact solutions of the relativistic Klein-Gordon equation for perturbed Coulomb potentials namely the Cornell potential, the Kratzer potential and the Killingbeck potential. We calculate the general exact expressions for the energies, corresponding wave functions and the allowed values of the parameters of the potential within the representation space of sl(2) Lie algebra. In addition, we show that the considered equations can be transformed into the Heun's differential equations and then we reproduce the results using the associated special functions. Also, we study the special case of the Coulomb potential and show that in the non-relativistic limit, the solution of the Klein-Gordon equation converges to that of Schrödinger equation.
Realization of collective strong coupling with ion Coulomb crystals in an optical cavity
DEFF Research Database (Denmark)
Herskind, Peter Fønss; Dantan, Aurélien; Marler, Joan
2009-01-01
Cavity quantum electrodynamics (CQED) focuses on understanding the interactions between matter and the electromagnetic field in cavities at the quantum level 1, 2 . In the past years, CQED has attracted attention 3, 4, 5, 6, 7, 8, 9 especially owing to its importance for the field of quantum...... crystal 16 and an optical field. The obtained coherence times are in the millisecond range and indicate that Coulomb crystals positioned inside optical cavities are promising for realizing a variety of quantum-information devices, including quantum repeaters 12 and quantum memories for light 17, 18...... . Moreover, cavity optomechanics 19 using Coulomb crystals might enable the exploration of similar phenomena investigated using more traditional solids, such as micro-mechanical oscillators 20 ....
First measurement with a new setup for low-energy Coulomb excitation studies at INFN LNL
Rocchini, M.; Hadyńska-Klȩk, K.; Nannini, A.; Valiente-Dobón, J. J.; Goasduff, A.; Testov, D.; John, P. R.; Mengoni, D.; Zielińska, M.; Bazzacco, D.; Benzoni, G.; Boso, A.; Cocconi, P.; Chiari, M.; Doherty, D. T.; Galtarossa, F.; Jaworski, G.; Komorowska, M.; Matejska-Minda, M.; Melon, B.; Menegazzo, R.; Napiorkowski, P.; Napoli, D. R.; Ottanelli, M.; Perego, A.; Ramina, L.; Rampazzo, M.; Recchia, F.; Riccetto, S.; Rosso, D.; Siciliano, M.; Sona, P.
2017-07-01
A new segmented particle detector, SPIDER, has been designed to be used as an ancillary device with the GALILEO γ-ray spectrometer, as well as with other multi-detector γ-ray arrays that will be available at LNL in the future (e.g. AGATA). To commission the SPIDER-GALILEO experimental setup, a multi-step Coulomb excitation experiment was carried out with a 240 MeV beam of 66Zn produced by the Tandem-XTU accelerator at INFN Laboratori Nazionali di Legnaro. The measured particle and γ-ray spectra are compared with the results of detailed GEANT4 simulations which used the Coulomb excitation cross sections, estimated with the computer code GOSIA, as an input. The preliminary results indicate that precise transition probabilities will be obtained which are essential for solving discrepancies reported in the literature for this nucleus.
Dynamic polarization by coulomb excitation in the closed formalism for heavy ion scattering
International Nuclear Information System (INIS)
Frahn, W.E.; Hill, T.F.
1978-01-01
We present a closed-form treatment of the effects of dynamic polarization by Coulomb excitation on the elastic scattering of deformed heavy ions. We assume that this interaction can be represented by an absorptive polarization potential. The relatively long range of this potential entails a relatively slow variation of the associated reflection function in l-space. This feature leads to a simple generalization of the closed formula derived previously for the elastic scattering amplitude of spherical heavy nuclei. We use both the polarization potential of Love et al. and the recent improved potential of Baltz et al. to derive explicit expressions for the associated reflection functions in a Coulomb-distorted eikonal approximation. As an example we analyze the elastic scattering of 90-MeV 18 O ions by 184 W and show that both results give a quantitative description of the data. (orig.) [de
Simbuca, using a graphics card to simulate Coulomb interactions in a penning trap
Van Gorp, S; Friedag, P; De Leebeeck, V; Tandecki, M; Weinheimer, C; Breitenfeldt, M; Traykov, E; Severijn, N; Mader, J; Soti, G; Iitaka, T; Herlert, A; Wauters, F; Zakoucky, D; Kozlov, V; Roccia, S
2011-01-01
In almost all cases, N-body simulations are limited by the computation time available. Coulomb interaction calculations scale with O(N(2)) with N the number of particles. Approximation methods exist already to reduce the computation time to O(NlogN) although calculating the interaction still dominates the total simulation time. We present Simbuca, a simulation package for thousands of ions moving in a Penning trap which will be applied for the WITCH experiment. Simbuca uses the output of the Cunbody-1 library, which calculates the gravitational interaction between entities on a graphics card, and adapts it for Coulomb calculations. Furthermore the program incorporates three realistic buffer gas models, the possibility of importing realistic electric and magnetic fieldmaps and different order integrators with adaptive step size and error control. The software is released under the GNU General Public License and free for use. Crown Copyright (C) 2010 Published by Elsevier B.V. All rights reserved.
Exact solution to the Coulomb wave using the linearized phase-amplitude method
Directory of Open Access Journals (Sweden)
Shuji Kiyokawa
2015-08-01
Full Text Available The author shows that the amplitude equation from the phase-amplitude method of calculating continuum wave functions can be linearized into a 3rd-order differential equation. Using this linearized equation, in the case of the Coulomb potential, the author also shows that the amplitude function has an analytically exact solution represented by means of an irregular confluent hypergeometric function. Furthermore, it is shown that the exact solution for the Coulomb potential reproduces the wave function for free space expressed by the spherical Bessel function. The amplitude equation for the large component of the Dirac spinor is also shown to be the linearized 3rd-order differential equation.
Incorporation of threshold phenomena in the three-body Coulomb continuum wavefunctions
International Nuclear Information System (INIS)
Berakdar, J.
1996-01-01
In this work a three-body Coulomb wavefunction for the description of two continuum electrons moving in the field of a nucleus is constructed such that the Wannier threshold law for double escape is reproduced and the asymptotic Coulomb boundary conditions as well as the Kato cusp conditions are satisfied. It is shown that the absolute value of the total cross section, as well as the spin asymmetry, are well described by the present approach. Further, the excess-energy sharing between the two escaping electrons is calculated and analysed in light of the Wannier theory predictions. This is the first time an analytical three-body wavefunction is presented which is asymptotically exact and capable of describing threshold phenomena. 37 refs., 3 figs
Coulomb explosion imaging of bromobenzene and bromophenol molecules following Br K-shell ionization
International Nuclear Information System (INIS)
Iwayama, H; Nagaya, K; Murakami, H; Ohmasa, Y; Yao, M
2010-01-01
We have performed multiple-ion coincidence momentum imaging measurements for bromobenzene and bromophenol molecules irradiated by hard x-ray photons at Br K-shell edge. Dominant fragment ions were singly charged monatomic ions H + , C + , O + and Br + . This indicates that parent molecules became highly charged through Auger cascade of Br core shell ionization. From an analysis of momentum vectors of ions, we found that the ejection directions of fragment ions strongly reflected the molecular structure of the neutral state. We can reproduce experimental results well by the trajectory analysis of fragment ions based on a Coulomb explosion model. This result shows that hard x-ray radiation enables us to apply Coulomb explosion imaging even for complex molecules such as benzene molecules.
Extraction of Coulomb crystals from a paul-trap ion source for nano-beam generation
International Nuclear Information System (INIS)
Izawa, Kenji; Ito, Kiyokazu; Higaki, Hiroyuki; Okamoto, Hiromi
2009-01-01
As is well-known, a single-species plasma confined in a compact trap system naturally forms a spatially ordered configuration near the absolute zero. Such a unique state of matter is called 'Coulomb crystal'. The emittance of this strongly coupled plasma is close to the ultimate limit, far below those of regular particle beams. This implies that, if we can somehow accelerate a crystal without serious heating, an ultralow-emittance beam becomes available. To test this idea, we produce a string Coulomb crystal in a linear Paul trap by laser cooling and then try to extract it by switching off the axial confinement potential. Preliminary experimental results indicate that it is possible to transport the crystal while roughly maintaining its linear ordered structure. (author)
Coulomb excitation of the two proton-hole nucleus $^{206}$Hg
We propose to use Coulomb excitation of the single magic two-proton-hole nucleus $^{206}$Hg. In a single-step excitation both the first 2$^{+}$ and the highly collective octupole 3$^{-}$ states will be populated. Thus, information on both quadrupole and octupole collectivity will be gained in this neutron-rich nucleus. Due to the high beam intensity, we will be able to observe multi-step Coulomb excitation as well, providing further test on theoretical calculations. The results will be used to improve the predictive power of the shell model for more exotic nuclei as we move to lighter N=126 nuclei. The experiment will use the new HIE-ISOLDE facility and the MINIBALL array, and will take advantage of the recently developed $^{206}$Hg beam from the molten lead target.
Coulomb Excitation of Neutron Deficient Sn-Isotopes using REX-ISOLDE
Di julio, D D; Kownacki, J M; Marechal, F; Andreoiu, C; Siem, S; Perrot, F; Van duppen, P L E; Napiorkowski, P J; Iwanicki, J S
2002-01-01
It is proposed to study the evolution of the reduced transition probabilities, B(E2; 0$^{+} \\rightarrow$ 2$^{+}$), for neutron deficient Sn isotopes by Coulomb excitation in inverse kinematics using REX-ISOLDE and the MINIBALL detector array. Measurements of the reduced transition matrix element for the transition between the ground state and the first excited 2$^{+}$ state in light even-even Sn isotopes provide a means to study e.g. core polarization effects in the $^{100}$Sn core. Previous attempts to measure this quantity have been carried out using the decay of isomeric states populated in fusion evaporation reactions. We thus propose to utilize the unique opportunity provided by REX-ISOLDE, after the energy upgrade to 3.1 MeV/u, to use the more model-independent approach of Coulomb excitation to measure this quantity in a number of isotopes in this region.
Onset of collectivity in $^{96,98}$Sr studied via Coulomb excitation
Clement, E; Dijon, A; de France, G; Bastin, B; Blazhev, A; Bree, N; Butler, P; Delahaye, P; Ekstrom, A; Georgiev, G; Hasan, N; Iwanicki, J; Jenkins, D; Korten, W; Larsen, A C; Ljungvall, J; Moschner, K; Napiorkowski, P; Pakarinen, J; Petts, A; Renstrom, T; Seidlitz, M; Siem, S; Sotty, C; Srebrny, J; Stefanescu, I; Tveten, G M; Van de Walle, J; Warr, N; Wrzosek-Lipska, K; Zielinska, M; Bauer, C; Bruyneel, B; Butterworth, J; Fitzpatrick, C; Fransen, C; GernhäUser, R; Hess, H; Lutter, R; Marley, P; Reiter, P; Siebeck, B; Vermeulen, M; Wiens, A; De Witte, H
2014-01-01
A rapid onset of quadrupole deformation is known to occur around the neutron number 60 in the neutron-rich Zr and Sr isotopes. This shape change has made the neutron-rich A = 100 region an active area of experimental and theoretical studies for many decades now. We report in this contribution new experimental results in the neutron rich 96,98Sr investigated by safe Coulomb excitation of radioactive beams at the REX-ISOLDE facility, CERN. Reduced transition probabilities and spectroscopic quadrupole moments have been extracted from the differential Coulomb excitation cross section supporting the scenario of shape coexistence/change at N=60. Future perspectives are presented including the recent experimental campaign performed at ILL-Grenoble.
Onset of collectivity in 96,98Sr studied via Coulomb excitation
Directory of Open Access Journals (Sweden)
Clément E.
2014-03-01
Full Text Available A rapid onset of quadrupole deformation is known to occur around the neutron number 60 in the neutron-rich Zr and Sr isotopes. This shape change has made the neutron-rich A = 100 region an active area of experimental and theoretical studies for many decades now. We report in this contribution new experimental results in the neutron rich 96,98Sr investigated by safe Coulomb excitation of radioactive beams at the REX-ISOLDE facility, CERN. Reduced transition probabilities and spectroscopic quadrupole moments have been extracted from the differential Coulomb excitation cross section supporting the scenario of shape coexistence/change at N=60. Future perspectives are presented including the recent experimental campaign performed at ILL-Grenoble.
Shapes of Exotic Nuclei by Single- and Multi-Step Coulomb Excitation
Allmond, J. M.; Clarion-Bareball Collaboration; Gretina-Chico2 Collaboration
2017-09-01
Coulomb excitation is a powerful technique for probing the shell structure, collectivity, and shapes of atomic nuclei through the measurement of electromagnetic moments. Single- and multi-step Coulomb excitation results from CLARION-BareBall at HRIBF-ORNL (e.g., 136Te) and GRETINA-CHICO2 at CARIBU-ANL (e.g., 106Mo and 106,110Ru) will be presented. A survey of the equipment, techniques, and results will be given. An emphasis will be placed on unique opportunities with 3-MeV/u beams and future directions at CARIBU and ReA3. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics.
International Nuclear Information System (INIS)
Dreizler, R.M.; Errea, L.F.; Henne, A.; Luedde, H.J.; Riera, A.; Sanchez, P.
1993-01-01
Close-coupling techniques often break down when transitions to a continuum or quasicontinuum cannot be neglected. This work describes an extension of a recently proposed method [L. F. Errea, L. Mendez, and A. Riera, Chem. Phys. Lett. 164, 261 (1989)] to deal with such situations, when the coupling terms involve Coulomb potentials. A connection with the method of packet states is made, and a preliminary application of the method is presented
Probing shape coexistence in neutron-deficient $^{72}$Se via low-energy Coulomb excitation
We propose to study the evolution of nuclear structure in neutron-deficient $^{72}$Se by performing a low-energy Coulomb excitation measurement. Matrix elements will be determined for low-lying excited states allowing for a full comparison with theoretical predictions. Furthermore, the intrinsic shape of the ground state, and the second 0$^{+}$ state, will be investigated using the quadrupole sum rules method.
Coulomb interaction and phonons in doped semiconducting and metallic two-dimensional materials
Schönhoff, Gunnar
2017-01-01
Two-dimensional (2D) materials present a rapidly developing field of research with sometimes highly unusual and uniquely two-dimensional physics. Starting with graphene, many recent studies have investigated 2D materials, with results for properties encompassing such different topics as Dirac electrons, charge ordering, and superconductivity. To get closer to a predictive theory of the phases of 2D materials, this thesis systematically tackles the previously unclear problem of the Coulomb int...
Electron impact excitation of positive ions calculated in the Coulomb-Born approximation
International Nuclear Information System (INIS)
Nakazaki, Shinobu; Hashino, Tasuke
1979-08-01
Theoretical results on the electron impact excitation of positive ions are surveyed through the end of 1978. As a guide to the available data, a list of references is made. The list shows ion species, transitions, energy range and methods of calculation for the respective data. Based on the literature survey, the validity of the Coulomb-Born approximation is investigated. Comparisons with the results of the close-coupling and the distorted-wave methods are briefly summarized. (author)
Quasi-Exact Coulomb Dynamics of n Charges n-1 of Which Are Equal
Directory of Open Access Journals (Sweden)
Wolodymyr Skrypnik
2017-01-01
Full Text Available For n≥3 point charges n-1 of which are negative and equal quasi-exact periodic solutions of their Coulomb equation of motion are found. These solutions describe a motion of the negative charges around a coordinate axis in such a way that their coordinates coincide with vertices of a regular polygon in planes perpendicular to the axis along which the positive charge moves. The Weinstein and center Lyapunov theorems are utilized.
Structure Theory for Extended Kepler-Coulomb 3D Classical Superintegrable Systems
Directory of Open Access Journals (Sweden)
Ernie G. Kalnins
2012-06-01
Full Text Available The classical Kepler-Coulomb system in 3 dimensions is well known to be 2nd order superintegrable, with a symmetry algebra that closes polynomially under Poisson brackets. This polynomial closure is typical for 2nd order superintegrable systems in 2D and for 2nd order systems in 3D with nondegenerate (4-parameter potentials. However the degenerate 3-parameter potential for the 3D extended Kepler-Coulomb system (also 2nd order superintegrable is an exception, as its quadratic symmetry algebra doesn't close polynomially. The 3D 4-parameter potential for the extended Kepler-Coulomb system is not even 2nd order superintegrable. However, Verrier and Evans (2008 showed it was 4th order superintegrable, and Tanoudis and Daskaloyannis (2011 showed that in the quantum case, if a second 4th order symmetry is added to the generators, the double commutators in the symmetry algebra close polynomially. Here, based on the Tremblay, Turbiner and Winternitz construction, we consider an infinite class of classical extended Kepler-Coulomb 3- and 4-parameter systems indexed by a pair of rational numbers (k_1,k_2 and reducing to the usual systems when k_1=k_2=1. We show these systems to be superintegrable of arbitrarily high order and work out explicitly the structure of the symmetry algebras determined by the 5 basis generators we have constructed. We demonstrate that the symmetry algebras close rationally; only for systems admitting extra discrete symmetries is polynomial closure achieved. Underlying the structure theory is the existence of raising and lowering constants of the motion, not themselves polynomials in the momenta, that can be employed to construct the polynomial symmetries and their structure relations.
Englert, G. W.
1971-01-01
A model of the random walk is formulated to allow a simple computing procedure to replace the difficult problem of solution of the Fokker-Planck equation. The step sizes and probabilities of taking steps in the various directions are expressed in terms of Fokker-Planck coefficients. Application is made to many particle systems with Coulomb interactions. The relaxation of a highly peaked velocity distribution of particles to equilibrium conditions is illustrated.
International Nuclear Information System (INIS)
Kumar, Rajiv; Sharma, Shagun; Singh, Pradeep; Kharab, Rajesh
2016-01-01
The energy-independent touching spheres schemes commonly used for the determination of the safe minimum value of the impact parameter for Coulomb excitation experiments are modified through the inclusion of an energy-dependent term. The touching spheres+3fm scheme after modification emerges out to be the best one while touching spheres+4fm scheme is found to be better in its unmodified form. (orig.)
Ultrafast dynamics of Coulomb correlated excitons in GaAs quantum wells
Energy Technology Data Exchange (ETDEWEB)
Mycek, M.A. [Univ. of California, Berkeley, CA (United States). Dept. of Physics]|[Lawrence Berkeley National Lab., CA (United States). Materials Sciences Div.
1995-12-01
The author measures the transient nonlinear optical response of room temperature excitons in gallium arsenide quantum wells via multi-wave mixing experiments. The dynamics of the resonantly excited excitons is directly reflected by the ultrafast decay of the induced nonlinear polarization, which radiates the detected multi-wave mixing signal. She characterizes this ultrafast coherent emission in both amplitude and phase, using time- and frequency-domain measurement techniques, to better understand the role of Coulomb correlation in these systems. To interpret the experimental results, the nonlinear optical response of a dense medium is calculated using a model including Coulomb interaction. She contributes three new elements to previous theoretical and experimental studies of these systems. First, surpassing traditional time-integrated measurements, she temporally resolves the amplitude of the ultrafast coherent emission. Second, in addition to measuring the third-order four-wave mixing signal, she also investigates the fifth-order six-wave mixing response. Third, she characterizes the ultrafast phase dynamics of the nonlinear emission using interferometric techniques with an unprecedented resolution of approximately 140 attoseconds. The author finds that effects arising from Coulomb correlation dominate the nonlinear optical response when the density of excitons falls below 3 {times} 10{sup 11} cm{sup {minus}2}, the saturation density. These signatures of Coulomb correlation are investigated for increasing excitation density to gradually screen the interactions and test the validity of the model for dense media. The results are found to be qualitatively consistent with both the predictions of the model and with numerical solutions to the semiconductor Bloch equations. Importantly, the results also indicate current experimental and theoretical limitations, which should be addressed in future research.
Inner shell Coulomb ionization by heavy charged particles studied by the SCA model
International Nuclear Information System (INIS)
Hansteen, J.M.
1976-12-01
The seven papers, introduced by the most recent, subtitled 'A condensed status review', form a survey of the work by the author and his colleagues on K-, L-, and M-shell ionisation by impinging protons, deuterons and α-particles in the period 1971-1976. The SCA model is discussed and compared with other approximations for inner shell Coulomb ionisation. The future aspects in this field are also discussed. (JIW)
Quasicrossings of potential curves in the two-Coulomb-center problem
Khmara, Viktor M.; Hnatič, Michal; Lazur, Volodymyr Yu.; Reity, Oleksandr K.
2018-02-01
The quasiclassical expression for the exchange interaction ΔE of potential curves at the points of their quasicrossing is found by means of the combined approach for solving the quantum mechanical two-Coulomb-center Z 1 eZ 2 problem. It can be used further for the calculation of cross sections of charge exchange processes between hydrogen or hydrogen-like atoms and bare nuclei.
The Coulomb dissociation of 8B and the 8B solar neutrino flux
International Nuclear Information System (INIS)
Gai, M.
1994-01-01
The Coulomb Dissociation of 8 B was measured using 46.5 MeV/u 8 B radioactive beams from the RIKEN-RIPS Radioactive Beam Facility, in an attempt to measure the 7 Be(p,γ) 8 B reaction at low energy, of relevance to estimating the 8 B solar neutrino flux. The experimental setup is discussed and the results are consistent with the lower value of S 17 measured by Filippone et al and Vaughn et al
The semiclassical approximation for L- and M-shell coulomb ionization by heavy charged particles
International Nuclear Information System (INIS)
Kocbach, L.
1975-08-01
The semiclassical approximation with straight line trajectories is applied to the Coulomb ionization of K-, L- and M-shells by heavy charged particles. The calculational aspects are discussed in detail. Scaling relations for the experimentally relevant quantities are derived. The theoretical predictions are compared with experimental data. The relation of the present work to earlier SCA results and the PWBA results is discussed in detail. (auth)
International Nuclear Information System (INIS)
Namgung, W.
1991-01-01
The well known requirement that physical theories should be gauge independent is not so apparent in the actual calculation of gauge theories, especially in the perturbative approach. In this paper the authors show that the Weyl, Coulomb, and unitary gauges of the scalar QED are manifestly equivalent in the context of the functional Schrodinger picture. Further, the three gauge conditions are shown equivalent to the covariant gauge in the way that they correspond to some specific cases of the latter
A preliminary study of the Gribov ambiguity in lattice SU(3) Coulomb gauge
Energy Technology Data Exchange (ETDEWEB)
Parrinello, C. (Physics Dept., New York Univ., NY (United States)); Petrarca, S. (Dipt. di Fisica, Rome-1 Univ. (Italy) INFN, Rome (Italy)); Vladikas, A. (Dipt. di Fisica, Rome-2 Univ. (Italy) INFN, Rome (Italy))
1991-10-10
We report on simulations of pure SU(3) gauge theory on a 10{sup 3}x20 lattice at {beta}=6.0 in the Coulomb gauge, from which the Gribov ambiguity appears to be maximal, in the sense that the gauge-fixing process is highly unstable with respect to variations of the starting configuration via random gauge transformations. We give a heuristic explanation of the larger number of Gribov copies in such a gauge with respect to the Landau gauge. (orig.).
Coulomb Blockade Anisotropic Magnetoresistance Effect in a (Ga,Mn)As Single-Electron Transistor
Czech Academy of Sciences Publication Activity Database
Wunderlich, J.; Jungwirth, Tomáš; Kaestner, B.; Irvine, A.C.; Shick, Alexander; Stone, N.; Wang, K. Y.; Rana, U.; Giddings, A.D.; Foxon, C. T.; Campion, R. P.; Williams, D.A.; Gallagher, B. L.
2006-01-01
Roč. 97, č. 7 (2006), 077201/1-077201/4 ISSN 0031-9007 R&D Projects: GA ČR GA202/05/0575; GA MŠk LC510 Grant - others:EPSRC(GB) GR/S81407/01 Institutional research plan: CEZ:AV0Z10100521 Keywords : anisotropic magnetoresistance * Coulomb blockade * single electron transistor Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 7.072, year: 2006
The relativistic Coulomb problem for particles with arbitrary half-integer spin
Czech Academy of Sciences Publication Activity Database
Niederle, Jiří; Nikitin, A. G.
2006-01-01
Roč. 39, - (2006), s. 10931-10944 ISSN 0305-4470 R&D Projects: GA MŠk 1P04LA211 Institutional research plan: CEZ:AV0Z10100502 Keywords : relativistic Coulomb problem * Kepler problem * integral particle with arbitrary half-integer spin Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 1.577, year: 2006
Shape Optimization in Three-Dimensional Contact Problems with Coulomb Friction
Czech Academy of Sciences Publication Activity Database
Beremlijski, P.; Haslinger, J.; Kočvara, Michal; Kučera, R.; Outrata, Jiří
2009-01-01
Roč. 20, č. 1 (2009), s. 416-444 ISSN 1052-6234 R&D Projects: GA AV ČR IAA100750802; GA AV ČR IAA1075402 Grant - others:European Commision(XE) FP6 - 30717; GA ČR(CZ) GA201/07/0294 Institutional research plan: CEZ:AV0Z10750506 Keywords : shape optimization * contact problems * Coulomb friction Subject RIV: BA - General Mathematics Impact factor: 1.429, year: 2009
Letting students discover the power, and the limits, of simple models: Coulomb's law
Bohacek, Peter; Vonk, Matthew; Dill, Joseph; Boehm, Emma
2017-09-01
The inverse-square law pops up all over. It's a simplified model of reality that describes light, sound, gravity, and static electricity. But when it's brought up in class, students are often just handed the equations. They rarely have an opportunity to discover Coulomb's law or Newton's law of gravitation for themselves. It's not hard to understand why. A quantitative demonstration of Coulomb's law can be difficult. The forces are smaller than many force sensors can measure and static electricity tends to be finicky. In addition, off-the-shelf units are expensive or difficult to use. As a result, many instructors skip this lab in favor of qualitative demonstrations or simulations. Adolf Cortel sought to remedy this by designing a straightforward experiment for measuring Coulomb's law using charged metalized-glass spheres (Christmas ornaments) and an electronic balance. Building on Cortel's design, we've made a series of video-based experiments that students can use to discover the relationships that underlie electric force.
Finite size and Coulomb corrections: from nuclei to nuclear liquid vapor phase diagram
International Nuclear Information System (INIS)
Moretto, L.G.; Elliott, J.B.; Phair, L.
2003-01-01
In this paper we consider the problem of obtaining the infinite symmetric uncharged nuclear matter phase diagram from a thermal nuclear reaction. In the first part we shall consider the Coulomb interaction which, because of its long range makes the definition of phases problematic. This Coulomb effect seems truly devastating since it does not allow one to define nuclear phase transitions much above A ∼ 30. However there may be a solution to this difficulty. If we consider the emission of particles with a sizable charge, we notice that a large Coulomb barrier Bc is present. For T << Bc these channels may be considered effectively closed. Consequently the unbound channels may not play a role on a suitably short time scale. Then a phase transition may still be definable in an approximate way. In the second part of the article we shall deal with the finite size problem by means of a new method, the complement method, which shall permit a straightforward extrapolation to the infinite system. The complement approach consists of evaluating the change in free energy occurring when a particle or cluster is moved from one (finite) phase to another. In the case of a liquid drop in equilibrium with its vapor, this is done by extracting a vapor particle of any given size from the drop and evaluating the energy and entropy changes associated with both the vapor particle and the residual liquid drop (complement)
JANUS - A setup for low-energy Coulomb excitation at ReA3
Lunderberg, E.; Belarge, J.; Bender, P. C.; Bucher, B.; Cline, D.; Elman, B.; Gade, A.; Liddick, S. N.; Longfellow, B.; Prokop, C.; Weisshaar, D.; Wu, C. Y.
2018-03-01
A new experimental setup for low-energy Coulomb excitation experiments was constructed in a collaboration between the National Superconducting Cyclotron Laboratory (NSCL), Lawrence Livermore National Laboratory (LLNL), and the University of Rochester and was commissioned at the general purpose beam line of NSCL's ReA3 reaccelerator facility. The so-called JANUS setup combines γ-ray detection with the Segmented Ge Array (SeGA) and scattered particle detection using a pair of segmented double-sided Si detectors (Bambino 2). The low-energy Coulomb excitation program that JANUS enables will complement intermediate-energy Coulomb excitation studies that have long been performed at NSCL by providing access to observables that quantify collectivity beyond the first excited state, including the sign and magnitude of excited-state quadrupole moments. In this work, the setup and its performance will be described based on the commissioning run that used stable 78Kr impinging onto a 1.09 mg/cm2208Pb target at a beam energy of 3.9 MeV/u.
Testing refined shell-model interactions in the sd shell: Coulomb excitation of Na26
Siebeck, B; Blazhev, A; Reiter, P; Altenkirch, R; Bauer, C; Butler, P A; De Witte, H; Elseviers, J; Gaffney, L P; Hess, H; Huyse, M; Kröll, T; Lutter, R; Pakarinen, J; Pietralla, N; Radeck, F; Scheck, M; Schneiders, D; Sotty, C; Van Duppen, P; Vermeulen, M; Voulot, D; Warr, N; Wenander, F
2015-01-01
Background: Shell-model calculations crucially depend on the residual interaction used to approximate the nucleon-nucleon interaction. Recent improvements to the empirical universal sd interaction (USD) describing nuclei within the sd shell yielded two new interactions—USDA and USDB—causing changes in the theoretical description of these nuclei. Purpose: Transition matrix elements between excited states provide an excellent probe to examine the underlying shell structure. These observables provide a stringent test for the newly derived interactions. The nucleus Na26 with 7 valence neutrons and 3 valence protons outside the doubly-magic 16O core is used as a test case. Method: A radioactive beam experiment with Na26 (T1/2=1,07s) was performed at the REX-ISOLDE facility (CERN) using Coulomb excitation at safe energies below the Coulomb barrier. Scattered particles were detected with an annular Si detector in coincidence with γ rays observed by the segmented MINIBALL array. Coulomb excitation cross sections...
No evidence of reduced collectivity in Coulomb-excited Sn isotopes
Kumar, R.; Saxena, M.; Doornenbal, P.; Jhingan, A.; Banerjee, A.; Bhowmik, R. K.; Dutt, S.; Garg, R.; Joshi, C.; Mishra, V.; Napiorkowski, P. J.; Prajapati, S.; Söderström, P.-A.; Kumar, N.; Wollersheim, H.-J.
2017-11-01
In a series of Coulomb excitation experiments the first excited 2+ states in semimagic Sn 112 ,116 ,118 ,120 ,122 ,124 isotopes were excited using a 58Ni beam at safe Coulomb energy. The B (E 2 ; 0+→2+) values were determined with high precision (˜3 %) relative to 58Ni projectile excitation. These results disagree with previously reported B (E 2 ↑) values [A. Jungclaus et al., Phys. Lett. B 695, 110 (2011)., 10.1016/j.physletb.2010.11.012] extracted from Doppler-shift attenuation lifetime measurements, whereas the reported mass dependence of B (E 2 ↑) values is very similar to a recent Coulomb excitation study [J. M. Allmond et al., Phys. Rev. C 92, 041303(R) (2015), 10.1103/PhysRevC.92.041303]. The stable Sn isotopes, key nuclei in nuclear structure, show no evidence of reduced collectivity and we, thus, reconfirm the nonsymmetric behavior of reduced transition probabilities with respect to the midshell A =116 .
On the Coulomb and Higgs branch formulae for multi-centered black holes and quiver invariants
Manschot, Jan; Sen, Ashoke
2013-01-01
In previous work we have shown that the equivariant index of multi-centered N=2 black holes localizes on collinear configurations along a fixed axis. Here we provide a general algorithm for enumerating such collinear configurations and computing their contribution to the index. We apply this machinery to the case of black holes described by quiver quantum mechanics, and give a systematic prescription -- the Coulomb branch formula -- for computing the cohomology of the moduli space of quiver representations. For quivers without oriented loops, the Coulomb branch formula is shown to agree with the Higgs branch formula based on Reineke's result for stack invariants, even when the dimension vector is not primitive. For quivers with oriented loops, the Coulomb branch formula parametrizes the Poincar\\'e polynomial of the quiver moduli space in terms of single-centered (or pure-Higgs) BPS invariants, which are conjecturally independent of the stability condition (i.e. the choice of Fayet-Iliopoulos parameters) and a...
Shape coexistence in the neutron-deficient mercury isotopes studied through Coulomb excitation
Bree, Nick
This thesis describes the analysis and results of a series of Coulomb-excitation experiments on even-even neutron-deficient mercury isotopes aimed at obtaining a more detailed description of shape coexistence. Two experimental campaigns have been undertaken in the Summer of 2007 and 2008. Pure beams of 182,184,186,188Hg were produced and accelerated at the REX-ISOLDE radioactive-beam facility, located at CERN (Geneva, Switzerland). The beams were guided to collide with a stable target to induce Coulomb excitation. The scattered particles were registered by a double-sided silicon strip detector, and the emitted gamma rays by the MINIBALL gamma-ray spectrometer. The motivation to study these mercury isotopes, focused around shape coexistence in atomic nuclei, is addressed in chapter 1, as well as an overview of the knowledge in this region of the nuclear chart. A theoretical description of Coulomb excitation is presented in the second chapter, while the third chapter describes the setup employed for the experim...
Coulomb excitations of low lying levels in 127I and 197Au
International Nuclear Information System (INIS)
Singh, K.P.; Tayal, D.C.; Hans, H.S.
1988-01-01
The low-lying levels of 127 I and 197 Au were Coulomb excited with 3.54 to 4.2 MeV protons. The reduced quadrupole transition probabilities of the 203, 374.9, 418, 618.4, 628.7, 651.1 and 745.5 keV states of 127 I, and the 268.8, 278.9, 502, and 547.5 keV states of 197 Au was measured from Coulomb excitation by observing the de-excitation gamma rays with a high resolution Ge(Li) detector. The low-energy protons were used for the first time to Coulomb-excite the two levels at 618.4 and 651.1 keV of 127 I and one level at 502 keV of 197 Au. The present experimental results are found in agreement with the existing experimental data except the B(E2) value of the level at 268.8 keV of 197 Au. (author). 4 figs., 4 tabs., 32 refs
Bauer, Jaroslaw
2001-04-01
A simple analytical approximation exists for the wavefunction of an unbound electron interacting both with a strong circularly polarized laser field and an atomic Coulomb potential (Reiss and Krainov 1994 Phys. Rev. A 50 R910). This wavefunction is the Volkov state with a first-order Coulomb correction coming from some perturbative expansion of the potential in the Kramers-Henneberger reference frame. The expansion is valid, if the distance from the centre of the Coulomb force is smaller than the classical radius of motion of a free electron in a plane-wave field. We improve the approximate Coulomb-Volkov wavefunction by including the next term in the perturbative expansion of the atomic potential.
International Nuclear Information System (INIS)
Correa, J.R.; Chang Yongbin; Ordonez, C.A.
2005-01-01
Collisional scattering is considered within a system of charged particles experiencing binary Coulomb interactions when the scale length for the range of each interaction is not isotropic and is not necessarily equal to the Debye length. For example, one or more dimensions of the system could be smaller than the Debye length. The effect is assessed by evaluating integrals over the impact cross section. Cutoffs on both the impact parameter and the Coulomb interaction potential are employed, and no assumption is made regarding the value of the Coulomb logarithm. Two expressions are found that have a dependence on the cutoff lengths, with one of the expressions being associated with the Coulomb logarithm. Collisional scattering within an electrostatic ion trap is considered by way of example
{sup 13,14}B(n, γ) via Coulomb Dissociation for Nucleosynthesis towards the r-Process
Energy Technology Data Exchange (ETDEWEB)
Altstadt, S.G., E-mail: s.altstadt@gsi.de [Goethe-Universität Frankfurt am Main, D-60438 Frankfurt am Main (Germany); GSI Helmholtzzentrum für Schwerionenforschung, D-64291 Darmstadt (Germany); Adachi, T. [KVI, University of Groningen, Zernikelaan 25, NL-9747 AA Groningen (Netherlands); Aksyutina, Y. [GSI Helmholtzzentrum für Schwerionenforschung, D-64291 Darmstadt (Germany); ExtreMe Matter Institute EMMI, GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt (Germany); Alcantara, J.; Alvarez-Pol, H. [Departamento de Física de Partículas, Universidade de Santiago de Compostela, 15706 Santiago de Compostela (Spain); Ashwood, N. [School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT (United Kingdom); Atar, L. [Institut für Kernphysik, Technische Universität Darmstadt, D-64289 Darmstadt (Germany); Aumann, T. [Institut für Kernphysik, Technische Universität Darmstadt, D-64289 Darmstadt (Germany); GSI Helmholtzzentrum für Schwerionenforschung, D-64291 Darmstadt (Germany); Avdeichikov, V. [Department of Physics, Lund University, S-22100 Lund (Sweden); Barr, M. [School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT (United Kingdom); Beceiro, S. [Departamento de Física de Partículas, Universidade de Santiago de Compostela, 15706 Santiago de Compostela (Spain); Bemmerer, D. [Helmholtz-Zentrum Dresden-Rossendorf, D-01328 Dresden (Germany); and others
2014-06-15
Radioactive beams of {sup 14,15}B produced by fragmentation of a primary {sup 40}Ar beam were directed onto a Pb target to investigate the neutron breakup within the Coulomb field. The experiment was performed at the LAND/R{sup 3}B setup. Preliminary results for the Coulomb dissociation cross sections as well as for the astrophysically interesting inverse reactions, {sup 13,14}B(n,γ), are presented.
Zhu, Yanfei; Hu, Aiping; Tang, Qunli; Zhang, Shiying; Deng, Weina; Li, Yanhua; Liu, Zheng; Fan, Binbin; Xiao, Kuikui; Liu, Jilei; Chen, Xiaohua
2018-03-05
A novel strategy is proposed to construct a compact-nanobox (CNB) structure composed of irregular nanograins (average diameter ≈ 10 nm), aiming to confine the electrode-electrolyte contact area and enhance initial Coulombic efficiency (ICE) of transition metal oxide (TMO) anodes. To demonstrate the validity of this attempt, CoO-CNB is taken as an example which is synthesized via a carbothermic reduction method. Benefiting from the compact configuration, electrolyte can only contact the outer surface of the nanobox, keeping the inner CoO nanograins untouched. Therefore, the solid electrolyte interphase (SEI) formation is reduced. Furthermore, the internal cavity leaves enough room for volume variation upon lithiation and delithiation, resulting in superior mechanical stability of the CNB structure and less generation of fresh SEI. Consequently, the SEI remains stable and spatially confined without degradation, and hence, the CoO-CNB electrode delivers an enhanced ICE of 82.2%, which is among the highest values reported for TMO-based anodes in lithium-ion batteries. In addition, the CoO-CNB electrode also demonstrates excellent cyclability with a reversible capacity of 811.6 mA h g -1 (90.4% capacity retention after 100 cycles). These findings open up a new way to design high-ICE electrodes and boost the practical application of TMO anodes.
Doser, D.I.; Olsen, K.B.; Pollitz, F.F.; Stein, R.S.; Toda, S.
2009-01-01
The occurrence of a right-lateral strike-slip earthquake in 1911 is inconsistent with the calculated 0.2-2.5 bar static stress decrease imparted by the 1906 rupture at that location on the Calaveras fault, and 5 yr of calculated post-1906 viscoelastic rebound does little to reload the fault. We have used all available first-motion, body-wave, and surface-wave data to explore possible focal mechanisms for the 1911 earthquake. We find that the event was most likely a right-lateral strikeslip event on the Calaveras fault, larger than, but otherwise resembling, the 1984 Mw 6.1 Morgan Hill earthquake in roughly the same location. Unfortunately, we could recover no unambiguous surface fault offset or geodetic strain data to corroborate the seismic analysis despite an exhaustive archival search. We calculated the static and dynamic Coulomb stress changes for three 1906 source models to understand stress transfer to the 1911 site. In contrast to the static stress shadow, the peak dynamic Coulomb stress imparted by the 1906 rupture promoted failure at the site of the 1911 earthquake by 1.4-5.8 bar. Perhaps because the sample is small and the aftershocks are poorly located, we find no correlation of 1906 aftershock frequency or magnitude with the peak dynamic stress, although all aftershocks sustained a calculated dynamic stress of ???3 bar. Just 20 km to the south of the 1911 epicenter, we find that surface creep of the Calaveras fault at Hollister paused for ~17 yr after 1906, about the expected delay for the calculated static stress drop imparted by the 1906 earthquake when San Andreas fault postseismic creep and viscoelastic relaxation are included. Thus, the 1911 earthquake may have been promoted by the transient dynamic stresses, while Calaveras fault creep 20 km to the south appears to have been inhibited by the static stress changes.
CWF and TABLE - Two Fortran programmes for the calculation of Coulomb penetration and shift factors
International Nuclear Information System (INIS)
Norton, D.S.; James, M.F.
1965-12-01
CWF and TABLE are Fortran programmes, written for the IBM 7090 and English-Electric Leo Marconi KDF9 computers, that calculate the penetration and shift factors for a charged particle in a Coulomb field. The numerical methods used are those of Lutz and Karvelis. The two programmes are very similar. Input to TABLE is in the form of the centre-of-mass co-ordinates. CWF is intended for use in calculating cross-sections for neutron-induced reactions which result in charged particle emission, and the input is in the form of the neutron energy in the laboratory frame of reference, together with other necessary reaction data. (author)
Scattering of {sup 6}He at energies around the Coulomb barrier
Energy Technology Data Exchange (ETDEWEB)
Sanchez-BenItez, A M [Departamento de Fisica Aplicada, Universidad de Huelva, E-21071 Huelva (Spain); Escrig, D [Instituto de Estructura de la Materia, CSIC, E-28006 Madrid (Spain); Alvarez, M A G [Departamento de Fisica Atomica, Molecular y Nuclear, Universidad de Sevilla, E-41080 Sevilla (Spain)] [and others
2005-10-01
We have measured elastic cross sections of the scattering of {sup 6}He at E{sub Lab} = 14, 16, 17, 18 and 22 MeV on {sup 208}Pb in the angular ranges of 20 deg. - 64 deg. and 135 deg. - 170 deg. A significant amount of {sup 4}He events is found at energies well below the Coulomb barrier, that becomes dominant above it. Optical model calculations have been performed including a dynamic polarization potential. Very large imaginary diffuseness parameter is needed in order to describe the experimental distributions.
Generalized relations among N-dimensional Coulomb Green's functions using fractional derivatives
International Nuclear Information System (INIS)
Blinder, S.M.; Pollock, E.L.
1989-01-01
Hostler [J. Math. Phys. 11, 2966 (1970)] has shown that Coulomb Green's functions of different dimensionality N are related by G (N+2) =OG (N) , where O is a first-order derivative operator in the variables x and y. Thus all the even-dimensional functions are connected, as are analogously the odd-dimensional functions. It is shown that the operations of functional differentiation and integration can further connect the even- to the odd-dimensional functions, so that Hostler's relation can be extended to give G (N+1) =O 1/2 G (N)
International Nuclear Information System (INIS)
Artemyev, A. N.; McConnell, S. R.; Surzhykov, A.; Najjari, B.; Voitkiv, A. B.
2011-01-01
We investigate the Coulomb excitation of highly charged ions colliding with diatomic molecules. In this process, the coherent interaction between the projectile electron and two molecular centers may cause clear interference patterns in the (collision) energy dependencies of the total cross sections and alignment parameters. We discuss such a Young-type interference for the particular case of the K→L excitation of hydrogen- and helium-like projectile ions. Calculations, performed for the scattering of these ions on nitrogen molecules, indicate that the interference effects are extremely sensitive to the collisional geometry and are pronounced only if the molecular axis is aligned almost parallel to the incident beam trajectory.
Resonant Coulomb excitation of atomic nuclei propagating through a crystal in the channeling mode
International Nuclear Information System (INIS)
Stepanov, A.V.
1996-01-01
The Coulomb-excitation total cross section and the distribution of decay products originating from a resonant state of a nucleus interacting with a crystal lattice has been calculated for the case of a single inelastic collision (with respect to internal degrees of freedom in a nucleus). These observables have been expressed in terms of time-dependent correlators which describe thermal oscillations of lattice nuclei and the motion of the center of mass of a nucleus propagating across a crystal target in the channelling mode. An expression generalizing the spectrum of equivalent photons calculated by the Weizsaecker-Williams method is given
Coulomb blockade in a Si channel gated by an Al single-electron transistor
Sun, L.; Brown, K. R.; Kane, B. E.
2007-01-01
We incorporate an Al-AlO_x-Al single-electron transistor as the gate of a narrow (~100 nm) metal-oxide-semiconductor field-effect transistor (MOSFET). Near the MOSFET channel conductance threshold, we observe oscillations in the conductance associated with Coulomb blockade in the channel, revealing the formation of a Si single-electron transistor. Abrupt steps present in sweeps of the Al transistor conductance versus gate voltage are correlated with single-electron charging events in the Si t...
Pan, R; Lefevre, T; Gillepsie, WA; CERN. Geneva. ATS Department
2016-01-01
Electro-optic (EO) techniques are increasingly used for longitudinal bunch profile measurements. A bunch profile monitor, based on electro-optic spectral decoding(EOSD), has been developed and demonstrated on the CALIFES beam line at CERN. The EO response is analysed using a frequency domain description, and two methods for extraction of absolute Coulomb field strengths from the electron bunch are demonstrated. Measurements at field strengths up to 1.3 MV/m agree with the expectation based on independent charge measurements.
Czech Academy of Sciences Publication Activity Database
Eck, Ch.; Jarušek, Jiří; Sofonea, M.
2010-01-01
Roč. 21, č. 3 (2010), s. 229-251 ISSN 0956-7925 R&D Projects: GA AV ČR IAA100750802 Institutional research plan: CEZ:AV0Z10190503 Keywords : elastic-vosco plastic material * dynamic contact problem * normal damped response * unilateral constraint * Coulomb friction * weak solution * penalitazion * smoothing Subject RIV: BA - General Mathematics Impact factor: 1.480, year: 2010 http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=7675484&fileId=S0956792510000045
Czech Academy of Sciences Publication Activity Database
Beremlijski, P.; Outrata, Jiří; Haslinger, Jaroslav; Pathó, R.
2014-01-01
Roč. 52, č. 5 (2014), s. 3371-3400 ISSN 0363-0129 R&D Projects: GA ČR(CZ) GAP201/12/0671 Grant - others:GA MŠK(CZ) CZ.1.05/1.1.00/02.0070; GA MŠK(CZ) CZ.1.07/2.3.00/20.0070 Institutional support: RVO:67985556 ; RVO:68145535 Keywords : shape optimization * contact problems * Coulomb friction * solution-dependent coefficient of friction * mathematical programs with equilibrium constraints Subject RIV: BA - General Mathematics Impact factor: 1.463, year: 2014 http://library.utia.cas.cz/separaty/2014/MTR/outrata-0434234.pdf
Coulomb Solutions from Improper Pseudo-Unitary Free Gauge Field Operator Translations
Directory of Open Access Journals (Sweden)
Andreas Aste
2014-12-01
Full Text Available Fundamental problems of quantum field theory related to the representation problem of canonical commutation relations are discussed within a gauge field version of a van Hove-type model. The Coulomb field generated by a static charge distribution is described as a formal superposition of time-like pseudo-photons in Fock space with a Krein structure. In this context, a generalization of operator gauge transformations is introduced to generate coherent states of Abelian gauge fields interacting with a charged background.
Green's function for motion in Coulomb-modified separable nonlocal potentials
Energy Technology Data Exchange (ETDEWEB)
Talukdar, B.; Laha, U.; Sasakawa, T.
1986-08-01
A closed form expression is derived for the outgoing wave radial Green's function G-script/sup (+)//sub l-italic/ (r-italic,r-italic') for motion in the Coulomb plus rank one separable nonlocal potential with form factor v-italic/sub l-italic/(r-italic) = 2/sup -//sup l-italic/ x (l-italicexclamation)/sup -1/ r-italic/sup l-italic/e-italic/sup -//sup ..beta..//sup >//sup l-italic/r-italic$. Some possible applications of the result are discussed.
Coulomb excitation of neutron-rich $^{134-136}$Sn isotopes
We propose to study excited states in the isotopes $^{134,136}$Sn by $\\gamma$-ray spectroscopy following "safe" Coulomb excitation. The experiment aims to investigate the evolution of quadrupole collectivity beyond the magic shell closure at N = 82 by the determination of B(E2) values and electric quadrupole moments $\\mathcal{Q}_2$. Recent shell-model calculations using realistic interactions predict possible enhanced collectivity in neutron-rich regions. Evidence for this could be obtained by this experiment. Furthermore, the currently unknown excitation energies of the 2$^+_{1}$ and 4$^+_{1}$ states in $^{136}$Sn will be measured for the first time.
Algebra with polynomial commutation relations for Zeeman effect in Coulomb-Dirac field
International Nuclear Information System (INIS)
Karasev, M.V.; Novikova, E.M.
2005-01-01
One studies a model of a particle motion in the field of electromagnetic monopole (the Coulomb-Dirac field) disturbed by homogeneous magnetic and inhomogeneous electric fields. The quantum averaging is followed by occurrence of the integrated system the Hamiltonian of which is represented by the algebra elements with polynomial commutation relations. One forms irreducible representations of the mentioned algebra and its hypergeometric coherent states. One obtains the representation of the eigenfunction of the assumption problem and specifies the asymptotics of eigenvalues in the first order of perturbation theory [ru
Dynamics of braking vehicles: from Coulomb friction to anti-lock braking systems
Energy Technology Data Exchange (ETDEWEB)
Tavares, J M [Instituto Superior de Engenharia de Lisboa, Avenida Conselheiro EmIdio Navarro 1, 1959-007 Lisboa (Portugal)], E-mail: jtavares@dem.isel.ipl.pt
2009-07-15
The dynamics of braking of wheeled vehicles is studied using the Coulomb approximation for the friction between road and wheels. The dependence of the stopping distance on the mass of the vehicle, on the number of its wheels and on the intensity of the braking torque is established. It is shown that there are two regimes of braking, with and without sliding. The advantage of using an anti-lock braking system (ABS) is put in evidence, and a quantitative estimate of its efficiency is proposed and discussed.
Efficient evaluation of Coulomb integrals in a mixed Gaussian and plane-wave basis
Czech Academy of Sciences Publication Activity Database
Čársky, Petr
2007-01-01
Roč. 107, č. 1 (2007), s. 56-62 ISSN 0020-7608 R&D Projects: GA AV ČR IAA100400501; GA AV ČR 1ET400400413 Grant - others:European Science Foundation (EIPAM)(XE) PESC7-20; U.S. National Science Foundation(US) OISE-0532040 Institutional research plan: CEZ:AV0Z40400503 Keywords : two-electron integrals * mixed plane-wave and Gaussian basis sets * Coulomb integrals Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.368, year: 2007
Cherkasov, O. Yu.; Zarodnyuk, A. V.; Bugrov, D. I.
2017-01-01
The range maximization problem and corresponding the brachistochrone problem with Coulomb, viscous friction and accelerating force are considered. A Maximum Principle procedure is applied to reduce optimal problem to the boundary-value problem for the system of two nonlinear differential equations. Solutions of this system are corresponding to the motion under singular control. The qualitative analysis of the solutions is carried out. It allows to install the characteristic properties of the trajectories, unnoticed in a number of publications as well as to confirm the hypothesis and the results of numerical calculations presented in other sources.
Balance between Coulombic interactions and physical confinement in silica hydrogel encapsulation.
Zhou, Yongyao; Yip, Wai Tak
2009-04-30
We examined the behavior of various entrapped guest molecules within silica hydrogel and evaluated the effect of Coulombic interactions and physical confinement on molecular mobility. Although rhodamine 6G (R6G) and fluorescein (FL) share similar size and molecular structure, their behavior in silica hydrogel was found to be dramatically different. A good majority of R6G was immobilized with little to no exchangeable molecules, whereas FL displayed a considerable amount of mobility in silica hydrogel. Moreover, silica hydrogel encapsulated R6G failed to gain mobility even under low pH or high ionic strength conditions to minimize Coulombic interactions, implying that encapsulated R6G molecules were inaccessible and likely trapped deep inside the silica matrix of a hydrogel. On the contrary, FL was relatively free to rotate and translate inside a silica hydrogel, implying that FL remained solvated in the solvent phase and was able to maintain its mobility throughout the hydrogel formation process. Fluorescence recovery after photobleaching measurements put the diffusion coefficient of FL in silica hydrogel at ca. 2.1 x 10(-6) cm(2) s(-1), about a factor of 3 slower than that in solution. The substantial difference in mobility between cationic R6G and anionic FL led us to conclude that the effect of Coulombic interactions on mobility is more dominating in hydrogel than in alcogel. Our results also suggest that Coulombic interactions are strong enough to influence the eventual placement of a guest molecule in a silica hydrogel, causing R6G and FL to reside in different microenvironments. This has a profound implication on the use of molecular probes to study silica hydrogel since a slight difference in physical attribute may result in very diverse observations even from identically prepared silica hydrogel samples. As demonstrated, the repulsion between FL and silica renders FL liquid-bound, making FL more suitable for monitoring the change in viscosity and physical
Elastic scattering of 10Be on 208Pb near the Coulomb barrier
International Nuclear Information System (INIS)
Kolata, J.J.; Aguilera, E.F.; Garcia-Martinez, H.; Martinez-Quiroz, E.; Becchetti, F.D.; Chen Yu; Lupton, J. H.; DeYoung, P.A.; Hinnefeld, J.D.; Peaslee, G.
2004-01-01
The elastic scattering of 10 Be on 208 Pb has been measured over a range of energies near the nominal Coulomb barrier. An excitation function for the total reaction cross section is obtained from the elastic-scattering angular distributions and compared with existing fusion data. Comparisons are also made with existing fusion, transfer/breakup, and elastic data for 9 Be incident on 209 Bi. A strong enhancement in the sub-barrier total reaction cross section for 9 Be+ 209 Bi relative to 10 Be+ 208 Pb is demonstrated
Elastic scattering and transfer in the 8Li+208Pb system near the Coulomb barrier
International Nuclear Information System (INIS)
Kolata, J.J.; Goldberg, V.Z.; Lamm, L.O.; Marino, M.G.; O'Keeffe, C.J.; Rogachev, G.; Aguilera, E.F.; Garcia-Martinez, H.; Martinez-Quiroz, E.; Rosales, P.; Becchetti, F.D.; O'Donnell, T.W.; Roberts, D.A.; Brown, J.A.; DeYoung, P.A.; Hinnefeld, J.D.; Shaheen, S.A.
2002-01-01
The interaction of 8 Li with 208 Pb has been studied over a range of energies near the nominal Coulomb barrier. An excitation function for the total reaction cross section is obtained from elastic-scattering angular distributions and compared with existing data for 6,7 Li scattering. The result of this comparison indicates that the interaction barrier for 8 Li+ 208 Pb is reduced by approximately 4 MeV relative to that of 7 Li. The yields of 7 Li and 4 He from breakup and/or transfer processes are determined, and compared with similar data for other light, weakly bound projectiles
The Coulomb gas representation of critical RSOS models on the sphere and the torus
International Nuclear Information System (INIS)
Foda, O.; Nienhuis, B.
1989-01-01
We derive the Coulomb gas formulation of the c<1 discrete unitary series, on the sphere and the torus, starting from the corresponding regime-III RSOS models on a square lattice with appropriate topology. We clarify the origin of the background charge, the screening charges, and the choice of operator representations in a correlation function. In the scaling limit, we obtain a bosonic action coupled to the background curvature in addition to topological terms that vanish on the Riemann sphere. Its Virasoro algebra has the central charge expected on the basis of comparing conformal dimensions. As an application, we derive general expressions for the correlation functions on the torus. (orig.)
The Coulomb gas representation of critical RSOS models on the sphere and the torus
Energy Technology Data Exchange (ETDEWEB)
Foda, O. (Rijksuniversiteit Utrecht (Netherlands). Inst. voor Theoretische Fysica); Nienhuis, B. (Rijksuniversiteit Leiden (Netherlands). Inst. Lorentz voor Theoretische Natuurkunde)
1989-10-02
We derive the Coulomb gas formulation of the c<1 discrete unitary series, on the sphere and the torus, starting from the corresponding regime-III RSOS models on a square lattice with appropriate topology. We clarify the origin of the background charge, the screening charges, and the choice of operator representations in a correlation function. In the scaling limit, we obtain a bosonic action coupled to the background curvature in addition to topological terms that vanish on the Riemann sphere. Its Virasoro algebra has the central charge expected on the basis of comparing conformal dimensions. As an application, we derive general expressions for the correlation functions on the torus. (orig.).
Energy dependence of the Coulomb-nuclear interference at small momentum transfers
International Nuclear Information System (INIS)
Selyugin, O.V.
1997-01-01
The analyzing power of the elastic proton-proton scattering at small momentum transfers and the effect of the Coulomb-nuclear interference are examined on the basis of the available experimental data at p L from 6 up to 200 GeV/c taking account of a phenomenological analysis at p L =6 GeV/c and of the dynamic high energy spin model. The structure of the spin-dependent elastic scattering amplitude at small momentum transfers is obtained. The predictions for the analyzing power at RHIC energies are made
Electromagnetic properties of sup 1 sup 6 sup 5 Ho inferred from Coulomb excitation
Iwanicki, J; Czosnyka, T; Choinski, J; Napiorkowski, P J; Loewe, M; Wuerkner, M; Srebrny, J
2003-01-01
The nucleus sup 1 sup 6 sup 5 Ho was Coulomb excited using sup 1 sup 6 O, sup 2 sup 0 Ne and sup 4 sup 0 Ar beams from the Warsaw Cyclotron. A model-independent analysis using the GOSIA code yielded a set of 26 reduced E2 matrix elements and 12 M1 matrix elements coupling the 13 low-lying excited states. A quadrupole sum rules approach was used to determine the deformation of the states. A remarkable change of the quadrupole deformation in one of the gamma-vibrational bands was found.
KLEIN: Coulomb functions for real lambda and positive energy to high accuracy
International Nuclear Information System (INIS)
Barnett, A.R.
1981-01-01
KLEIN computes relativistic Schroedinger (Klein-Gordon) equation solutions, i.e. Coulomb functions for real lambda > - 1, Fsub(lambda)(eta,x), Gsub(lambda)(eta,x), F'sub(lambda)(eta,x) and G'sub(lambda)(eta,x) for real kappa > 0 and real eta, - 10 4 4 . Hence it is also suitable for Bessel and spherical Bessel functions. Accuracies are in the range 10 -14 -10 -16 in oscillating region, and approx. equal to 10 -30 on an extended precision compiler. The program is suitable for generating Klein-Gordon wavefunctions for matching in pion and kaon physics. (orig.)
COULCC: A continued-fraction algorithm for Coulomb functions of complex order with complex arguments
International Nuclear Information System (INIS)
Thompson, I.J.; Barnett, A.R.
1985-01-01
The routine COULCC calculates both the oscillating and the exponentially varying Coulomb wave functions, and their radial derivations, for complex eta(Sommerfeld parameter), complex energies and complex angular momenta. The functions for uncharged scattering (spherical Bessels) and cylindrical Bessel functions are special cases which are more easily solved. Two linearly independent solutions are found, in general, to the differential equation f''(x)+g(x)f(x)=0, where g(x) has x 0 , x -1 and x -2 terms, with coefficients 1, -2eta and -lambda(lambda+1), respectively. (orig.)
DEFF Research Database (Denmark)
Ruban, Andrei; Skriver, Hans Lomholt
2002-01-01
We have used the locally self-consistent Green's-function (LSGF) method in supercell calculations to establish the distribution of the net charges assigned to the atomic spheres of the alloy components in metallic alloys with different compositions and degrees of order. This allows us to determine......-site local interaction zone. We demonstrate that the basic mechanism that governs the charge distribution is the screening of the net charges of the alloy components that makes the direct Coulomb interactions short ranged. In the atomic-sphere approximation, this screening appears to be almost independent...
A Particle-in-Cell simulation of temporal plasma echo in the presence of Coulomb collisions
Wu, B. Z.; Nishimura, Y.; Wang, C. P.
2017-10-01
Particle-in-Cell simulation is developed to study temporal plasma echo of electron plasma wave. By imposing two external pulse electric fields to the plasma (pulse-like in time) the echo signal is observed. Coulomb collisional effect manifests itself as a shift of the echo peak and the damping of the peak amplitude, which can be seen by adding (rather phenomenological) frictional force to the electron equation of motion. A first principle based binary collision model is incorporated into the numerical simulation.
Measurements of shape co-existence in $^{182,184}$Hg using Coulomb excitation
Voulot, D; Paul, E S; Siem, S; Czosnyka, T; Napiorkowski, P J; Iwanicki, J S
2007-01-01
We propose to exploit the unique capability of ISOLDE to provide post-accelerated $^{182,184}$Hg ions from the REX facility to enable the lowest states of these nuclei to be Coulomb excited. By measuring the $\\gamma$-ray yields using the MINIBALL array we can measure the transition and diagonal E2 matrix elements for these states. This will give quantitative information about the nature of the shape coexistence in these nuclei and allow the sign of the quadrupole deformation be determined for the first time. We require 24 shifts to fulfill the aims of the experiment.
Can Hall drag be observed in Coulomb coupled quantum wells in a magnetic field?
DEFF Research Database (Denmark)
Hu, Ben Yu-Kuang
1997-01-01
We study the transresistivity rho(21) (or equivalently, the drag rate) of two Coulomb-coupled quantum wells in the presence of a perpendicular magnetic field, using semi-classical transport theory. Elementary arguments seem to preclude any possibility of observation of ''Hall drag'' (i.e., a non......-zero off-diagonal component in rho(21)). We show that these arguments are specious, and in fact Hall drag can be observed at sufficiently high temperatures when the intralayer transport time tau has significant energy-dependence around the Fermi energy epsilon(F). The ratio of the Hall to longitudinal...
Coulomb Drag as a Probe of Coupled Plasmon Modes in Parallel Quantum Wells
DEFF Research Database (Denmark)
Flensberg, Karsten; Hu, Ben Yu-Kuang
1994-01-01
We show theoretically that the Coulomb drag rate between two parallel quasi-two-dimensional electron gases with equal Fermi velocities is substantially enhanced by the coupled acoustic and optic plasmon modes at temperatures T≳0.2TF (where TF is the Fermi temperature) for experimentally relevant...... parameters. The acoustic mode causes a sharp upturn in the scaled drag rate with increasing temperature at T≈0.2TF. Other experimental signatures of the plasmon-dominated drag rate are a d-3 dependence on the well separation d and a peak as a function of relative densities at matched Fermi velocities....
Hamiltonian approach to QCD in Coulomb gauge: From the vacuum to finite temperatures
Directory of Open Access Journals (Sweden)
Reinhardt H.
2016-01-01
Full Text Available The variational Hamiltonian approach to QCD in Coulomb gauge is reviewedand the essential results obtained in recent years are summarized. First the results for thevacuum sector are discussed, with a special emphasis on the mechansim of confinementand chiral symmetry breaking. Then the deconfinement phase transition is described byintroducing temperature in the Hamiltonian approach via compactification of one spatialdimension. The effective action for the Polyakov loop is calculated and the order of thephase transition as well as the critical temperatures are obtained for the color group SU(2 and SU(3. In both cases, our predictions are in good agreement with lattice calculations.
Bastin, B; Kruecken, R; Larsen, A; Rahkila, P J; Srebrny, J; Clement, E; Wadsworth, R; Syed naeemul, H; Peura, P J; Siem, S; Hadynska-klek, K; Habs, D; Napiorkowski, P J; Diriken, J V J; Iwanicki, J S
Coulomb excitation measurements to study the shape coexistence and quadrupole collectivity of the low-lying levels in neutron-deficient Pb nuclei are proposed. Even-mass $^{188−192}$Pb nuclei will be post-accelerated at REX-ISOLDE in order to measure transition probabilities and quadrupole moments for the first excited states. In combination with results obtained in lifetime measurements, this will allow the sign of the quadrupole deformation parameter to be extracted for the first time for 2$^{+}$ states in the even-mass $^{188−192}$Pb nuclei.
How to determine the handedness of single molecules using Coulomb explosion imaging
International Nuclear Information System (INIS)
Pitzer, Martin
2017-01-01
This tutorial is based on a doctoral thesis that was shortlisted for the 2016 AMOP dissertation prize of the German Physical Society (DPG). The principal achievement of the thesis was to use Coulomb explosion imaging (CEI) to determine the microscopic handedness (‘chirality’) of molecular structures on a single-molecule level. It thus shows how a technique developed in atomic physics can address a long-standing problem in chemistry. Owing to these disparate backgrounds, the tutorial has two facets: on the one hand, the history of molecular chirality and recent developments are very briefly reviewed. On the other hand, an account is given of different experimental approaches to CEI, on the physical processes in light-induced Coulomb explosion and—most importantly—on the aspects that are relevant when designing and performing such an experiment. As structural chirality occurs only in polyatomic molecules, special attention will be given to multiple ionization and multi-coincidence measurements. A short discussion of the results presented in earlier papers is given, followed by an outlook on experiments that are under way or can realistically be performed within the next years. (phd tutorial)
Coulombic faulting from the grain scale to the geophysical scale: lessons from ice
Energy Technology Data Exchange (ETDEWEB)
Weiss, Jerome [Laboratoire de Glaciologie et Geophysique de l' Environnement, CNRS, 54 rue Moliere, BP 96, 38402 St Martin d' Heres Cedex (France); Schulson, Erland M, E-mail: weiss@lgge.obs.ujf-grenoble.f, E-mail: Erland.M.Schulson@Dartmouth.ED [Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755 (United States)
2009-11-07
Coulombic faulting, a concept formulated more than two centuries ago, still remains pertinent in describing the brittle compressive failure of various materials, including rocks and ice. Many questions remain, however, about the physical processes underlying this macroscopic phenomenology. This paper reviews the progress made in these directions during the past few years through the study of ice and its mechanical behaviour in both the laboratory and the field. Fault triggering is associated with the formation of specific features called comb-cracks and involves frictional sliding at the micro(grain)-scale. Similar mechanisms are observed at geophysical scales within the sea ice cover. This scale-independent physics is expressed by the same Coulombic phenomenology from laboratory to geophysical scales, with a very similar internal friction coefficient ({mu} {approx} 0.8). On the other hand, the cohesion strongly decreases with increasing spatial scale, reflecting the role of stress concentrators on fault initiation. Strong similarities also exist between ice and other brittle materials such as rocks and minerals and between faulting of the sea ice cover and Earth's crust, arguing for the ubiquitous nature of the underlying physics.
Coulomb excitation of $^{182-184}$ Hg: Shape coexistence in the neutron-deficient lead region
We put forward a study of the interplay between individual nucleon behavior and collective degrees of freedom in the nucleus, as manifested in shape coexistence in the neutron-deficient lead region. As a first step of this experimental campaign, we propose to perform Coulomb excitation on light mercury isotopes to probe their excited states and determine transitional and diagonal E2 matrix elements, especially reducing the current uncertainties. The results from previous Coulomb excitation measurements in this mass region performed with 2.85 MeV/u beams from REX-ISOLDE have shown the feasibility of these experiments. Based on our past experience and the results obtained, we propose a detailed study of the $^{182-184}$Hg nuclei, that exhibit a pronounced mixing between 2 low-lying excited states of apparently different deformation character, using the higher energy beams from HIE-ISOLDE which are crucial to reach our goal. The higher beam energy should result in an increased sensitivity with respect to the qua...
How to determine the handedness of single molecules using Coulomb explosion imaging
Pitzer, Martin
2017-08-01
This tutorial is based on a doctoral thesis that was shortlisted for the 2016 AMOP dissertation prize of the German Physical Society (DPG). The principal achievement of the thesis was to use Coulomb explosion imaging (CEI) to determine the microscopic handedness (‘chirality’) of molecular structures on a single-molecule level. It thus shows how a technique developed in atomic physics can address a long-standing problem in chemistry. Owing to these disparate backgrounds, the tutorial has two facets: on the one hand, the history of molecular chirality and recent developments are very briefly reviewed. On the other hand, an account is given of different experimental approaches to CEI, on the physical processes in light-induced Coulomb explosion and—most importantly—on the aspects that are relevant when designing and performing such an experiment. As structural chirality occurs only in polyatomic molecules, special attention will be given to multiple ionization and multi-coincidence measurements. A short discussion of the results presented in earlier papers is given, followed by an outlook on experiments that are under way or can realistically be performed within the next years.
Cycling capacity recovery effect: A coulombic efficiency and post-mortem study
Wilhelm, Jörn; Seidlmayer, Stefan; Keil, Peter; Schuster, Jörg; Kriele, Armin; Gilles, Ralph; Jossen, Andreas
2017-10-01
The analysis of lithium-ion battery aging relies on correct differentiation between irreversible and reversible capacity changes. Anode overhang regions have been observed to influence Coulombic Efficiency (CE) measurements through lithium diffusion into and out of these areas, complicating precise capacity determination. This work presents an analysis of the extent of graphite anode overhang lithiation after calendar storage by means of local X-ray diffraction (XRD), CE measurements, and color change analysis. We found LiC12 lithiation of the anode overhang area after 20 month storage at 40 °C at high state of charge (SoC) and partial lithiation (LiC18) at medium SoC storage at 40 °C and 25 °C. Graphite color changes in the overhang areas are observed and consistent with the state of lithiation measured by XRD. Coulombic efficiencies greater than unity and increasing capacity during 1200 h of cycling are detected for high SoC storage cells. The capacity difference between high and low storage SoC batteries decreases by up to 40 mAh (3.6% of nominal capacity) after cycling compared to tests directly after storage. Consequently, the size of the anode overhang areas as well as the battery storage temperature and duration need to be considered in CE analysis and state of health assessment.
Mathur, D; Rajgara, F A
2010-08-14
Intense, ultrashort pulses of 800 nm laser light (12 fs, approximately 4 optical cycles) of peak intensity 5x10(14) W cm(-2) have been used to irradiate gas-phase Xe(n) clusters (n=500-25,000) so as to induce multiple ionization and subsequent Coulomb explosion. Energy distributions of exploding ions are measured in the few-cycle domain that does not allow sufficient time for the cluster to undergo expansion due to Coulombic and hydrodynamic pressures. This results in overall dynamics that appear to be significantly different to those in the many-cycle regime. One manifestation is that the maximum ion energies are measured to be much lower than those obtained when longer pulses of the same intensity are used. Ion yields are cluster-size independent but polarization dependent in that they are significantly larger when the polarization is perpendicular to the detection axis than along it. This unexpected behavior is qualitatively rationalized in terms of a spatially anisotropic shielding effect induced by the electronic charge cloud within the cluster.
Rigorous study of the mean field approximation of Debye and Hueckel for Coulomb systems
International Nuclear Information System (INIS)
Kennedy, T.G.
1984-01-01
The statistical mechanics of a classical charge symmetric Coulomb system is studied in three dimensions in the limit that the plasma parameter (the inverse temperature divided by the Debye length) goes to zero. To make the system stable, a short range interaction, e.g., hard cores is included. This short range interaction is allowed to go to zero as the plasma parameter goes to zero. Debye and Hueckel used a mean field approximation to give a nonrigorous study of Coulomb systems in his limit. For a system with no external charge distribution, it is shown that the pressure, density, and correlation functions are asymptotic to their Debye-Hueckel approximations. These approximations consist of the ideal gas term plus a term of one lower order in the plasma parameter. The main tools are the Sine-Gordon transformation, the Mayer expansion, and some new correlation inequalities. The sine-Gordon transformation and the Mayer expansion are used to express the observables as functional integrals with respect to a Gaussian measure. The correlation inequalities help control these functional integrals
ANALYSING POST-SEISMIC DEFORMATION OF IZMIT EARTHQUAKE WITH INSAR, GNSS AND COULOMB STRESS MODELLING
Directory of Open Access Journals (Sweden)
R. A. Barut
2016-06-01
Full Text Available On August 17th 1999, a Mw 7.4 earthquake struck the city of Izmit in the north-west of Turkey. This event was one of the most devastating earthquakes of the twentieth century. The epicentre of the Izmit earthquake was on the North Anatolian Fault (NAF which is one of the most active right-lateral strike-slip faults on earth. However, this earthquake offers an opportunity to study how strain is accommodated in an inter-segment region of a large strike slip fault. In order to determine the Izmit earthquake post-seismic effects, the authors modelled Coulomb stress changes of the aftershocks, as well as using the deformation measurement techniques of Interferometric Synthetic Aperture Radar (InSAR and Global Navigation Satellite System (GNSS. The authors have shown that InSAR and GNSS observations over a time period of three months after the earthquake combined with Coulomb Stress Change Modelling can explain the fault zone expansion, as well as the deformation of the northern region of the NAF. It was also found that there is a strong agreement between the InSAR and GNSS results for the post-seismic phases of investigation, with differences less than 2mm, and the standard deviation of the differences is less than 1mm.
Transverse Kelvin-Helmholtz instability with parallel electron dynamics and Coulomb collisions
International Nuclear Information System (INIS)
Satyanarayana, P.; Lee, Y.C.; Huba, J.D.
1987-01-01
Electron parallel dynamics and Coulomb collisions are included in the analysis of the transverse Kelvin-Helmholtz instability. The electrons are treated kinetically while the ions are treated in the fluid limit. It is shown that in the collisionless case, for an imhomogeneous velocity profile V(x) = V 0 tanh (x/L) the Kelvin-Helmholtz instability is stable for k/sub z//k/sub y/>(V 0 /Lω/sub l//sub h/)K/sub y/L [2(1-k/sub y/ 2 L 2 )]/sup 1/2/ in the limit ω-k/sub y/V 0 >>k/sub z/v/sub e/. Here V 0 is the flow velocity, L is the scale length of the velocity shear layer, k/sub z/ and k/sub y/ are the parallel and perpendicular wave numbers, respectively, ω/sub l//sub h/ = (Ω/sub e/Ω/sub i/)/sup 1/2/, and v/sub e/ is the electron thermal velocity. The stabilization of the mode is shown to be caused by the compressional energy given to the electrons parallel to B. In the collisional limit, Coulomb collisions are shown to increase the unstable k/sub z/ domain becasue they inhibit the electron motion parallel to B. Applications to the high-latitude ionosphere are discussed. Copyright American Geophysical Union 1987
Understanding the fusion cross section among light nuclei around the Coulomb barrier
Directory of Open Access Journals (Sweden)
Del Zoppo Antonio
2017-01-01
Full Text Available In this work we investigate fusion induced by a radioactive 8Li projectile on a 4He gas target, at center-of-mass energies between 0.6 and 5 MeV. The main result is the tendency of the dimensionless fusion cross section σπλ2 to form well visible plateaus alternated to steep rises. This is likely to be the most genuine consequence of the discrete nature of the intervening angular momenta observed so far in fusion reactions right above the Coulomb barrier. A partial-wave analysis, exclusively based on a pure quantal penetration fusion model, identifies a remarkably low-height barrier. Indeed, these plateaus allow enhanced experimental sensitivity to the fusion barrier given that the most barrier-sensitive lowest partial waves are well separated. We expect that the present results for 8Li+4He will promote further investigations of the fusion reaction mechanism between very light ions at energies much below the interaction barrier. For the moment, we believe that understanding the plateau origin in the cross section above the barrier will almost certainly be useful to corroborate the extrapolation to the important astrophysical region below the Coulomb barrier, not only in the case of the 8Li+4He fusion but also for other systems, such as the 12C+12C.
Understanding the fusion cross section among light nuclei around the Coulomb barrier
Del Zoppo, Antonio; La Cognata, Marco
2017-11-01
In this work we investigate fusion induced by a radioactive 8Li projectile on a 4He gas target, at center-of-mass energies between 0.6 and 5 MeV. The main result is the tendency of the dimensionless fusion cross section to form well visible plateaus alternated to steep rises. This is likely to be the most genuine consequence of the discrete nature of the intervening angular momenta observed so far in fusion reactions right above the Coulomb barrier. A partial-wave analysis, exclusively based on a pure quantal penetration fusion model, identifies a remarkably low-height barrier. Indeed, these plateaus allow enhanced experimental sensitivity to the fusion barrier given that the most barrier-sensitive lowest partial waves are well separated. We expect that the present results for 8Li+4He will promote further investigations of the fusion reaction mechanism between very light ions at energies much below the interaction barrier. For the moment, we believe that understanding the plateau origin in the cross section above the barrier will almost certainly be useful to corroborate the extrapolation to the important astrophysical region below the Coulomb barrier, not only in the case of the 8Li+4He fusion but also for other systems, such as the 12C+12C.
Coulomb excitation of neutron-rich odd-$A$ Cd isotopes
Reiter, P; Kruecken, R; Gernhaeuser, R A; Kroell, T; Leske, J; Marginean, N M
We propose to study excited states in the odd-${A}$ isotopes $^{123,125,127}$Cd by ${\\gamma}$-ray spectroscopy following "safe" Coulomb excitation. The experiment aims to determine the B(E2) values connecting excited states with the ground state as well as the long-lived (11/2$^{-}$) isomer. The proposed study profits from the unique capability of ISOLDE to produce beams containing Cd in the ground state or in the isomeric state. Our recent results on the neutron-rich even-A Cd nuclei appear to show that these nuclei may possess some collectivity beyond that calculated by modern shell-model predictions. Beyond-mean-field calculations also predict these nuclei to be weakly deformed. These facets are surprising considering their proximity to the doubly magic $^{132}$Sn. Coulomb-excitation studies of odd-${A}$ Cd isotopes may give a unique insight into the deformation-driving roles played by different orbits in this region. Such studies of the onset of collectivity become especially important in light of recent...
Hamiltonian Approach to QCD in Coulomb Gauge: A Survey of Recent Results
Directory of Open Access Journals (Sweden)
H. Reinhardt
2018-01-01
Full Text Available We report on recent results obtained within the Hamiltonian approach to QCD in Coulomb gauge. Furthermore this approach is compared to recent lattice data, which were obtained by an alternative gauge-fixing method and which show an improved agreement with the continuum results. By relating the Gribov confinement scenario to the center vortex picture of confinement, it is shown that the Coulomb string tension is tied to the spatial string tension. For the quark sector, a vacuum wave functional is used which explicitly contains the coupling of the quarks to the transverse gluons and which results in variational equations which are free of ultraviolet divergences. The variational approach is extended to finite temperatures by compactifying a spatial dimension. The effective potential of the Polyakov loop is evaluated from the zero-temperature variational solution. For pure Yang–Mills theory, the deconfinement phase transition is found to be second order for SU(2 and first order for SU(3, in agreement with the lattice results. The corresponding critical temperatures are found to be 275 MeV and 280 MeV, respectively. When quarks are included, the deconfinement transition turns into a crossover. From the dual and chiral quark condensate, one finds pseudocritical temperatures of 198 MeV and 170 MeV, respectively, for the deconfinement and chiral transition.
Low-energy Coulomb excitation of neutron-rich zinc isotopes
Van de Walle, J; Behrens, T; Bildstein, V; Blazhev, A; Cederkäll, J; Clément, E; Cocolios, T E; Davinson, T; Delahaye, P; Eberth, J; Ekström, A; Fedorov, D V; Fedosseev, V; Fraile, L M; Franchoo, S; Gernhäuser, R; Georgiev, G; Habs, D; Heyde, K; Huber, G; Huyse, M; Ibrahim, F; Ivanov, O; Iwanicki, J; Jolie, J; Kester, O; Köster, U; Kröll, T; Krücken, R; Lauer, M; Lisetskiy, A F; Lutter, R; Marsh, B A; Mayet, P; Niedermaier, O; Pantea, M; Raabe, R; Reiter, P; Sawicka, M; Scheit, H; Schrieder, G; Schwalm, D; Seliverstov, M D; Sieber, T; Sletten, G; Smirnova, N; Stanoiu, M; Stefanescu, I; Thomas, J C; Valiente-Dobón, J J; Van Duppen, P; Verney, D; Voulot, D; Warr, N; Weisshaar, D; Wenander, F; Wolf, B H; Zielinska, M
2009-01-01
At the radioactive ion beam facility REX-ISOLDE, neutron-rich zinc isotopes were investigated using low-energy Coulomb excitation. These experiments have resulted in B(E2,20) values in 74-80Zn, B(E2,42) values in 74,76Zn and the determination of the energy of the first excited 2 states in 78,80Zn. The zinc isotopes were produced by high-energy proton- (A=74,76,80) and neutron- (A=78) induced fission of 238U, combined with selective laser ionization and mass separation. The isobaric beam was postaccelerated by the REX linear accelerator and Coulomb excitation was induced on a thin secondary target, which was surrounded by the MINIBALL germanium detector array. In this work, it is shown how the selective laser ionization can be used to deal with the considerable isobaric beam contamination and how a reliable normalization of the experiment can be achieved. The results for zinc isotopes and the N=50 isotones are compared to collective model predictions and state-of-the-art large-scale shell-model calculations, i...
Fusion and particle transfer around the Coulomb-Barrier in intermediate systems
International Nuclear Information System (INIS)
Pascholati, P.R.
1989-01-01
The most important characteristics of fusion reactions below and around the Coulomb-barrier are summarized. Experimental fusion cross sections for typical systems are discussed and compared with current formulae obtained from semi-classical and quantum tunneling approaches. The influence of nucleons transfer in the enhancement of the fusion cross section below the Coulomb-barrier is also shown. Sub-barrier fusion cross sections for the systems 35,37 Cl + 58,64 Ni and 33 S + 90,91,92 Zr, and near-barrier cross sections of all important transfer channels have been measured using the XTU-TANDEM at Legnaro, Italy. In 35,37 Cl + 58,64 Ni systems, the motivation further investigated was the influence of the valence proton in the enhancement of the sub-barrier fusion cross section. The data are discussed in comparison with the similar data of 34,36 S + 58,64 Ni with the aim of revealing the influence of coupled proton transfer channels. Calculations were performed using the simplified coupled channel code CCFUS including ''pick-up'' of one and two neutrons and ''stripping'' of two neutrons channels. Signatures of positive Q-values transfer channels coupled to fusion were clearly identified. For the 33 S + 90,91,92 Zr systems taking into account the coupling effects between transfer and fusion and using the semi-classical approach, transfer form-factors were extracted and succesfully employed to described the isotopic effects in fusion enhancement. (Author) [es
One hundred and fifty years of Coulomb stress history along the California-Nevada border, USA
Verdecchia, Alessandro; Carena, Sara
2015-02-01
The region north of the Garlock Fault between the Sierra Nevada and Death Valley has experienced at least eight Mw ≥ 6 earthquakes in historical times, beginning with the 1872, Mw 7.5, Owens Valley earthquake. Furthermore, since 1978, the Long Valley Caldera has been undergoing periods of unrest, with earthquake swarms and resurgence. Our goal is to determine whether the 1872 Owens Valley earthquake and the caldera unrest have influenced the evolution of seismicity in the area. We model the evolution of coseismic, postseismic, and interseismic Coulomb stress change (Coulomb failure stress (ΔCFS)) in the region due to both Mw ≥ 6 earthquakes and caldera inflation in the last 150 years. Our results show that the 1872 Owens Valley earthquake has an important influence on subsequent events, strongly encouraging faulting in northern Owens Valley while inhibiting it elsewhere. There is also a correlation between caldera inflation and seismicity in northern Owens Valley, evidenced by the west-to-east migration of earthquakes from the Long Valley Caldera toward the White Mountains immediately following the 1978 caldera inflation event. Finally, we show that a total ΔCFS increase of up to 30 bars in the last 150 years has occurred on part of the White Mountains fault, making it a possible candidate for the next major earthquake in this region.
Hartree corrections in a mean-field limit for fermions with Coulomb interaction
Petrat, Sören
2017-06-01
We consider the many-body dynamics of fermions with Coulomb interaction in a mean-field scaling limit where the kinetic and potential energy are of the same order for large particle numbers. In the considered limit the spatial variation of the mean-field is small. We prove two results about this scaling limit. First, due to the small variation, i.e., small forces, we show that the many-body dynamics can be approximated by the free dynamics with an appropriate phase factor with the conjectured optimal error term. Second, we show that the Hartree dynamics gives a better approximation with a smaller error term. In this sense, assuming that the error term in the first result is optimal, we derive the Hartree equations from the many-body dynamics with Coulomb interaction in a mean-field scaling limit. , which features invited work from the best early-career researchers working within the scope of J. Phys. A. This project is part of the Journal of Physics series’ 50th anniversary celebrations in 2017. Sören Petrat was selected by the Editorial Board of J. Phys. A as an emerging talent.
Coulomb Excitation of a Neutron-Rich $^{88}$Kr Beam Search for Mixed Symmetry States
Andreoiu, C; Napiorkowski, P J; Iwanicki, J S
2002-01-01
We propose to use the ISOLDE/REX/MINIBALL/CD set-up to perform a Coulomb Excitation experiment with a $^{88}$Kr radioactive beam. The motivation includes a search for $Mixed$ $Symmetry$ states predicted by the IBM-2 model, gathering more spectroscopy data about the $^{88}$Kr nucleus and extending shape coexistence studies (performed previously by the proposers for neutron-deficient Kr isotopes) to the neutron-rich side. The proposed experiment will provide data complementary to the Coulomb Excitation of a relativistic $^{88}$Kr beam proposed by D. Tonev et al. for a RISING experiment. A total of 12 days of beam time is necessary for the experiment, equally divided into two runs. One run with a 2.2 MeV/A beam energy on a $^{48}$Ti target and a second run with the maximum available REX energy of 3.1 MeV/A on a $^{208}$Pb target are requested. Using either a UC$_{x}$ or ThC$_{x}$ fissioning primary target coupled with a plasma source by a cooled transfer line seems to be the best choice for the proposed experime...
The structure of low-lying states in ${}^{140}$Sm studied by Coulomb excitation
Klintefjord, M.; Görgen, A.; Bauer, C.; Bello Garrote, F.L.; Bönig, S.; Bounthong, B.; Damyanova, A.; Delaroche, J.P.; Fedosseev, V.; Fink, D.A.; Giacoppo, F.; Girod, M.; Hoff, P.; Imai, N.; Korten, W.; Larsen, A.C.; Libert, J.; Lutter, R.; Marsh, B.A.; Molkanov, P.L.; Naïdja, H.; Napiorkowski, P.; Nowacki, F.; Pakarinen, J.; Rapisarda, E.; Reiter, P.; Renstrøm, T.; Rothe, S.; Seliverstov, M.D.; Siebeck, B.; Siem, S.; Srebrny, J.; Stora, T.; Thöle, P.; Tornyi, T.G.; Tveten, G.M.; Van Duppen, P.; Vermeulen, M.J.; Voulot, D.; Warr, N.; Wenander, F.; De Witte, H.; Zielińska, M.
2016-05-02
The electromagnetic structure of $^{140}$Sm was studied in a low-energy Coulomb excitation experiment with a radioactive ion beam from the REX-ISOLDE facility at CERN. The $2^+$ and $4^+$ states of the ground-state band and a second $2^+$ state were populated by multi-step excitation. The analysis of the differential Coulomb excitation cross sections yielded reduced transition probabilities between all observed states and the spectroscopic quadrupole moment for the $2_1^+$ state. The experimental results are compared to large-scale shell model calculations and beyond-mean-field calculations based on the Gogny D1S interaction with a five-dimensional collective Hamiltonian formalism. Simpler geometric and algebraic models are also employed to interpret the experimental data. The results indicate that $^{140}$Sm shows considerable $\\gamma$ softness, but in contrast to earlier speculation no signs of shape coexistence at low excitation energy. This work sheds more light on the onset of deformation and collectivit...
Study of Ground State Wave-function of the Neutron-rich 29,30Na Isotopes through Coulomb Breakup
Directory of Open Access Journals (Sweden)
Rahaman A.
2014-03-01
Full Text Available Coulomb breakup of unstable neutron rich nuclei 29,30Na around the ‘island of inversion’ has been studied at energy around 434 MeV/nucleon and 409 MeV/nucleon respectively. Four momentum vectors of fragments, decay neutron from excited projectile and γ-rays emitted from excited fragments after Coulomb breakup are measured in coincidence. For these nuclei, the low-lying dipole strength above one neutron threshold can be explained by direct breakup model. The analysis for Coulomb breakup of 29,30Na shows that large amount of the cross section yields the 28Na, 29Na core in ground state. The predominant ground-state configuration of 29,30Na is found to be 28Na(g.s⊗νs1/2 and 29Na(g.s⊗νs1/2,respectively.
International Nuclear Information System (INIS)
Zhou, X.L.; Zhao, T.S.; An, L.; Wei, L.; Zhang, C.
2015-01-01
An issue with conventional vanadium redox flow batteries (VRFB) with Nafion membranes is the crossover of vanadium ions, resulting in low coulombic efficiency and rapid decay in capacity. In this work, a VRFB with a polybenzimidazole (PBI) membrane is tested and compared with the Nafion system. Results show that the PBI-based VRFB exhibits a substantially higher coulombic efficiency of up to 99% at current densities ranging from 20 mA cm −2 to 80 mA cm −2 . More importantly, it is demonstrated that the PBI-based VRFB has a capacity decay rate of as low as 0.3% per cycle, which is four times lower than that of the Nafion system (1.3% per cycle). The improved coulombic efficiency and cycling performance are attributed to the low crossover of vanadium ions through the PBI membrane
International Nuclear Information System (INIS)
Zhang Xiangao; Fang Zhonghui; Chen Kunji; Xu Jun; Huang Xinfan
2011-01-01
We present an approach to fabricate a silicon nanowire relying on the proximity effect in electron beam lithography with a low acceleration voltage system by designing the exposure patterns with a rhombus sandwiched between two symmetric wedges. The reproducibility is investigated by changing the number of rhombuses. A device with a silicon nanowire is constructed on a highly doped silicon-on-insulator wafer to measure the electronic transport characteristics. Significant nonlinear behavior of current-voltage curves is observed at up to 150 K. The dependence of current on the drain voltage and back-gate voltage shows Coulomb blockade oscillations at 5.4 K, revealing a Coulomb island naturally formed in the nanowire. The mechanism of formation of the Coulomb island is discussed.
Mourokh, L.; Wixforth, A.; Beil, F.; Bichler, M.; Wegscheider, W.; Blick, R. H.
2017-10-01
A quantum dot is created within a suspended nanobridge containing a two-dimensional electron gas. The electron current through this dot exhibits well-pronounced Coulomb blockade oscillations. When surface acoustic waves (SAW) are driven through the nanobridge, Coulomb blockade peaks are shifted. To explain this feature, we derive the expressions for the quantum dot level populations and electron currents through these levels and show that SAW-induced Rabi oscillations lead to the observed phenomenology.
Geilhufe, Matthias; Achilles, Steven; Köbis, Markus Arthur; Arnold, Martin; Mertig, Ingrid; Hergert, Wolfram; Ernst, Arthur
2015-11-01
For a reliable fully-relativistic Korringa-Kohn-Rostoker Green function method, an accurate solution of the underlying single-site scattering problem is necessary. We present an extensive discussion on numerical solutions of the related differential equations by means of standard methods for a direct solution and by means of integral equations. Our implementation is tested and exemplarily demonstrated for a spherically symmetric treatment of a Coulomb potential and for a Mathieu potential to cover the full-potential implementation. For the Coulomb potential we include an analytic discussion of the asymptotic behaviour of irregular scattering solutions close to the origin (r\\ll 1 ).
Study of the elastic scattering of {sup 6}He on {sup 208}Pb at energies around the Coulomb barrier
Energy Technology Data Exchange (ETDEWEB)
Sanchez-Benitez, A.M. [Departamento de Fisica Aplicada, Universidad de Huelva, E-21071 Huelva (Spain); Centre de Recherches du Cyclotron, Universite Catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Escrig, D. [Instituto de Estructura de la Materia, CSIC, E-28006 Madrid (Spain); Alvarez, M.A.G.; Andres, M.V. [Departamento de Fisica Atomica, Molecular y Nuclear, Universidad de Sevilla, E-41080 Sevilla (Spain); Angulo, C. [Centre de Recherches du Cyclotron, Universite Catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Borge, M.J.G. [Instituto de Estructura de la Materia, CSIC, E-28006 Madrid (Spain); Cabrera, J. [Centre de Recherches du Cyclotron, Universite Catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Cherubini, S. [INFN Laboratori Nazionali del Sud, I-95123 Catania (Italy); Demaret, P. [Centre de Recherches du Cyclotron, Universite Catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Espino, J.M. [Dept. de Fisica Atomica, Molecular y Nuclear, Universidad de Sevilla, E-41080 Sevilla (Spain); Figuera, P. [INFN Laboratori Nazionali del Sud, I-95123 Catania (Italy); Freer, M. [School of Physics and Astronomy, University of Birmingham, B15 2TT Birmingham (United Kingdom); Garcia-Ramos, J.E. [Departamento de Fisica Aplicada, Universidad de Huelva, E-21071 Huelva (Spain); Gomez-Camacho, J. [Dept. de Fisica Atomica, Molecular y Nuclear, Universidad de Sevilla, E-41080 Sevilla (Spain); Gulino, M. [INFN Laboratori Nazionali del Sud, I-95123 Catania (Italy); Kakuee, O.R. [Van der Graaff Laboratory, Nuclear Research Centre, AEOI, PO Box 14155-1339, Tehran (Iran, Islamic Republic of); Martel, I. [Dept. de Fisica Aplicada, Universidad de Huelva, E-21071 Huelva (Spain)], E-mail: imartel@uhu.es; Metelko, C. [School of Physics and Astronomy, University of Birmingham, B15 2TT Birmingham (United Kingdom); Moro, A.M. [Dept. de Fisica Atomica, Molecular y Nuclear, Universidad de Sevilla, E-41080 Sevilla (Spain)] (and others)
2008-04-15
The elastic scattering of {sup 6}He on {sup 208}Pb has been measured at laboratory energies of 14, 16, 18 and 22 MeV. These data were analyzed using phenomenological Woods-Saxon form factors and optical model calculations. A semiclassical polarization potential was used to study the effect of the Coulomb dipole polarizability. Evidence for long range absorption, partially arising from Coulomb dipole polarizability, is reported. The energy variation of the optical potential was found to be consistent with the dispersion relations which connect the real and imaginary parts of the potential.
Stark spectroscopy of Coulomb interactions in individual InAs/GaAs self-assembled quantum dots
International Nuclear Information System (INIS)
Kowalik, K.; Krebs, O.; Senellart, P.; Lemaitre, A.; Eble, B.; Kudelski, A.; Voisin, P.; Gaj, J.
2006-01-01
We present results of polarization-resolved micro-photoluminescence (μ-PL) experiments on self-organized InAs/GaAs (QDs). We have investigated how Coulomb interactions are modified by application of an electric field. We observed systematic variation of bright exciton splitting for different electric field configurations (applied in the quantum dot plane or along the sample growth axis). The results show also dependence of direct Coulomb interactions of carriers inside the dots, manifested by changes of PL line position of charged excitons (X + and X - ) with respect to the neutral excitonic line. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)
International Nuclear Information System (INIS)
Field, J H
2006-01-01
It is demonstrated how all the mechanical equations of classical electromagnetism (CEM) may be derived from only Coulomb's inverse square force law, special relativity and Hamilton's principle. The instantaneous nature of the Coulomb force in the centre-of-mass frame of two interacting charged objects, mediated by the exchange of space-like virtual photons, is predicted by quantum electrodynamics (QED). The interaction Lagrangian of QED is shown to be identical, in the appropriate limit, to the potential energy term in the Lorentz-invariant Lagrangian of CEM. A comparison is made with the Feynman-Wheeler action-at-a-distance formulation of CEM
Transition from the Kondo effect to a Coulomb blockade in an electron shuttle
International Nuclear Information System (INIS)
Zhang Rong; Chu Wei-Dong; Duan Su-Qing; Yang Ning
2013-01-01
We investigate the effect of the mechanical motion of a quantum dot on the transport properties of a quantum dot shuttle. Employing the equation of motion method for the nonequilibrium Green's function, we show that the oscillation of the dot, i.e., the time-dependent coupling between the dot's electron and the reservoirs, can destroy the Kondo effect. With the increase in the oscillation frequency of the dot, the density of states of the quantum dot shuttle changes from the Kondo-like to a Coulomb-blockade pattern. Increasing the coupling between the dot and the electrodes may partly recover the Kondo peak in the spectrum of the density of states. Understanding of the effect of mechanical motion on the transport properties of an electron shuttle is important for the future application of nanoelectromechanical devices
Coulomb-driven energy boost of heavy ions for laser-plasma acceleration.
Braenzel, J; Andreev, A A; Platonov, K; Klingsporn, M; Ehrentraut, L; Sandner, W; Schnürer, M
2015-03-27
An unprecedented increase of kinetic energy of laser accelerated heavy ions is demonstrated. Ultrathin gold foils have been irradiated by an ultrashort laser pulse at a peak intensity of 8×10^{19} W/ cm^{2}. Highly charged gold ions with kinetic energies up to >200 MeV and a bandwidth limited energy distribution have been reached by using 1.3 J laser energy on target. 1D and 2D particle in cell simulations show how a spatial dependence on the ion's ionization leads to an enhancement of the accelerating electrical field. Our theoretical model considers a spatial distribution of the ionization inside the thin target, leading to a field enhancement for the heavy ions by Coulomb explosion. It is capable of explaining the energy boost of highly charged ions, enabling a higher efficiency for the laser-driven heavy ion acceleration.