Search results for "Calculation"

showing 10 items of 594 documents

The CC3 model : An iterative coupled cluster approach including connected triples

1997

An alternative derivation of many-body perturbation theory (MBPT) has been given, where a coupled cluster parametrization is used for the wave function and the method of undetermined Lagrange multipliers is applied to set up a variational coupled cluster energy expression. In this variational formulation, the nth-order amplitudes determine the energy to order 2n+1 and the nth-order multipliers determine the energy to order 2n+2. We have developed an iterative approximate coupled cluster singles, doubles, and triples model CC3, where the triples amplitudes are correct through second order and the singles amplitudes are treated without approximations due to the unique role of singles as appro…

PhysicsMany-body problemsIterative methodIterative methodsGeneral Physics and AstronomyRelaxation (iterative method)Function (mathematics)Perturbation theoryFull configuration interactionUNESCO::FÍSICA::Química físicaPhysics and Astronomy (all)Coupled clusterCoupled cluster calculationsPerturbation theory ; Many-body problems ; Coupled cluster calculations ; Iterative methods ; Wave functions ; Variational techniquesComputational chemistryPerturbation theoryPhysical and Theoretical ChemistryPhysics::Chemical PhysicsWave function:FÍSICA::Química física [UNESCO]ParametrizationWave functionsMathematical physicsVariational techniques
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Fine structure in the beta-delayed proton decay of 33Ar

1996

9 pages, 2 figures, 2 tables.-- PACS nrs.: 21.60.Cs; 23.40.−s; 27.30.+t; 29.30.Ep.

PhysicsMeasured beta-delayed protons Ep IpNuclear and High Energy PhysicsDeduced relative spectroscopic amplitudesAr-33 (from 1 GeV p on Nb-foil target selective mass separation)Proton decaySHELL modelShell nucleiShell-model calculationGas-Si telescope spectrometerShell modelEmissionBeta-delayed proton decayAmplitudeAtomic orbitalExcited stateBeta (plasma physics)Nuclear Physics - ExperimentAtomic physicsNuclear Physics A
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S-matrix formulation of mesoscopic systems and evanescent modes.

2009

The Landauer-Butikker formalism is an important formalism to study mesoscopic systems. Its validity for linear transport is well established theoretically as well as experimentally. Akkermans et al [Phys. Rev. Lett. {\bf 66}, 76 (1991)] had shown that the formalism can be extended to study thermodynamic properties like persistent currents. It was earlier verified for simple one dimensional systems. We study this formula very carefully and conclude that it requires reinterpretation in quasi one dimension. This is essentially because of the presence of evanescent modes in quasi one dimension.

PhysicsMesoscopic physicsFormalism (philosophy of mathematics)Evanescent waveCondensed Matter - Mesoscale and Nanoscale PhysicsQuantum mechanicsMesoscale and Nanoscale Physics (cond-mat.mes-hall)FOS: Physical sciencesGeneral Materials ScienceCondensed Matter PhysicsCondensed Matter::Mesoscopic Systems and Quantum Hall EffectCalculation methodsS-matrixJournal of physics. Condensed matter : an Institute of Physics journal
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Translationally invariant treatment of pair correlations in nuclei - II. Tensor correlations

1998

We study the extension of our translationally invariant treatment of few-body nuclear systems to include tensor forces and correlations. It is shown that a direct application of our method is not as successful for realistic V6 interactions as our previous results for V4 potentials suggested. We investigate the cause in detail for the case of $^4$He, and show that a combination of our method with that of Jastrow-correlated wave functions seems to be a lot more powerful, thereby suggesting that for mildly to strongly repulsive forces such a hybrid procedure may be an appropriate description.

PhysicsNuclear and High Energy PhysicsCLOSED-SHELL NUCLEI; MONTE-CARLO CALCULATIONS; MODEL-CALCULATIONS; COORDINATE SPACE; CBF THEORY; POTENTIALS; CLUSTERS; SYSTEMS; STATE; HE-4Nuclear Theory/dk/atira/pure/subjectarea/asjc/3100/3106V6 forcesFOS: Physical sciencesFísicaInvariant (physics)A ≤ 16Translational invarianceNuclear Theory (nucl-th)Tensor correlationsJastrow correlationsWave functionMathematical physics
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Sensitive search for near-symmetric and super-asymmetric fusion-fission of the superheavy element Flerovium (Z=114)

2021

Physics letters / B 820, 136601 (2021). doi:10.1016/j.physletb.2021.136601

PhysicsNuclear and High Energy PhysicsFusionComponent (thermodynamics)FissionProjectilePhysicsQC1-999chemistry.chemical_elementIsotopes of flerovium530FleroviumSuperheavy elementchemistryNuclear fission dynamicsYield (chemistry)Mass spectrumddc:530Atomic physicsNuclear ExperimentMicroscopic model calculations
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Linear response strength functions with iterative Arnoldi diagonalization

2009

We report on an implementation of a new method to calculate RPA strength functions with iterative non-hermitian Arnoldi diagonalization method, which does not explicitly calculate and store the RPA matrix. We discuss the treatment of spurious modes, numerical stability, and how the method scales as the used model space is enlarged. We perform the particle-hole RPA benchmark calculations for double magic nucleus 132Sn and compare the resulting electromagnetic strength functions against those obtained within the standard RPA.

PhysicsNuclear and High Energy PhysicsNuclear TheoryIterative methodNuclear TheoryFOS: Physical sciencesCalculation methodsNuclear Theory (nucl-th)Quantum mechanicsIsotopes of tinPhysics::Atomic and Molecular ClustersApplied mathematicsSpurious relationshipRandom phase approximationNuclear theoryNumerical stability
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Total and inelastic cross sections at LHC ats=7  TeVand beyond

2011

We discuss expectations for the total and inelastic cross sections at LHC CM energies $\sqrt{s}=7\text{ }\text{ }\mathrm{TeV}$ and 14 TeV obtained in an eikonal minijet model augmented by soft gluon ${k}_{t}$-resummation, which we describe in some detail. We present a band of predictions which encompass recent LHC data and suggest that the inelastic cross section described by two-channel eikonal models include only uncorrelated processes. We show that this interpretation of the model is supported by the LHC data.

PhysicsNuclear and High Energy PhysicsParticle physicsLarge Hadron ColliderEikonal equationHigh Energy Physics::PhenomenologyUncorrelatedEikonal approximationCalculation methodsGluonNuclear physicsCross section (physics)High Energy Physics::ExperimentBosonPhysical Review D
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Forward hadron production in pA collisions beyond leading order

2017

In this talk, we report our recent progress on pinning down the cause of negativity in the NLO single inclusive hadron production in pA collisions at forward rapidity.

PhysicsNuclear and High Energy PhysicsParticle physicsta114010308 nuclear & particles physicsHadronperturbative calculationsFOS: Physical sciencesNegativity effect01 natural sciencesNuclear physicsHigh Energy Physics - PhenomenologyHigh Energy Physics - Phenomenology (hep-ph)color transparencyfactorization0103 physical sciencesProduction (economics)Color transparencyRapidityPerturbation theory (quantum mechanics)010306 general physicsNuclear and Particle Physics Proceedings
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Experimental evidence for chirality in the odd-A 105Rh

2004

Abstract High-spin states in 105 Rh were populated by the 96 Zr( 13 C, p3n) reaction at beam energies of 51 and 58 MeV, and studied using the EUROBALL IV γ -ray spectrometer and the DIAMANT charged particle array. A pair of nearly degenerate Δ I = 1 three-quasiparticle bands with the same spins and parity have been observed. Comparison of the experimental results with tilted axis cranking calculations confirms the chiral character of the two bands, while arguments based on the excitation of particles within the π g 9 / 2 ν ( h 11 / 2 ) 2 configuration of the yrast band and comparison with the previously observed γ band exclude the other possible interpretations. This is the first experiment…

PhysicsNuclear and High Energy PhysicsSpins010308 nuclear & particles physics[PHYS.NEXP] Physics [physics]/Nuclear Experiment [nucl-ex]Chiral partner bandsYrastDegenerate energy levelsParity (physics)[PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex]Tilted axis cranking01 natural sciences21.10.Re; 21.60.-n; 23.20.Lv; 27.60.+jCore-quasiparticle coupling calculationsCharged particleThree-quasiparticle configuration0103 physical sciencesQuasiparticleAtomic physics010306 general physicsChirality (chemistry)ExcitationPhysics Letters B
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Modeling moderated proportional neutron counters using the Geant4 toolkit and the application to detection of fast neutron burst

2014

PhysicsNuclear reactionEnergy absorptionNuclear engineeringMonte Carlo methodNeutronNucleonNeutron temperatureCalculation methodsProceedings of 10th Latin American Symposium on Nuclear Physics and Applications — PoS(X LASNPA)
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