共查询到20条相似文献,搜索用时 15 毫秒
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A new ansatz for the correlated ground state of the many-nucleon system is proposed which results in obtaining a modified Quasiparticle Random Phase Approximation (QRPA). An additional degree of freedom is introduced which allows to determine variationally the ground state simultaneously with solving the QRPA equations. This new approach, QRPA with an optimal ground state, is studied within the proton-neutron Lipkin model. New solutions have been found, in the range of the interaction strength where the standard QRPA formalism does not work. A relation between one of them and the solution obtained within a semi-classical approach is established. A detailed study of the expectation value of the quasiparticle number operator in the ground state and the transition amplitude for the two-neutrino double beta Fermi decay, is also presented. 相似文献
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讨论了建立在相对论平均场基态的相对论无规位相近似研究中的一致性问题. 研究表明考虑费米海和Dirac海的粒子 空穴激发对核的同位旋标量巨共振的能量有很大的影响. The fully consistent relativistic random phase approximation (RRPA) built on the relativist mean field (RMF) ground state is presented. The fully consistent RRPA requires that the nuclear RMF wave function and the RRPA renormalization are calculated in a same effective Lagrangian. A theoretically complete treatment of the RRPA at the mean field level with no sea approximation must include not only the usual particle hole states, but also the pairs formed from the occupied Fermi states and Dirac states. Effects of inclusion of Dirac sea states in various multipole excitations are investigated. Considerable effects on the isoscalar giant multipole resonances are observed. 相似文献
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The fully consistent relativistic continuum random phase approximation (RCRPA) has been constructed in the momentum representation in the first part of this paper. In this part we describe the numerical details for solving the Bethe-Salpeter equation. The numerical results are checked by the inverse energy weighted sum rules in the isoscalar giant monopole resonance, which are obtained from the constraint relativistic mean field theory and also calculated with the integration of the RCRPA strengths. Good agreement between them is achieved. We study the effects of the self-consistency violation, particularly the currents and Coulomb interaction to various collective multipole excitations. Using the fully consistent RCRPA method, we investigate the properties of isoscalar and isovector collective multipole excitations for some stable and exotic from light to heavy nuclei. The properties of the resonances, such as the centroid energies and strength distributions are compared with the experimental data as well as with results calculated in other models. 相似文献
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A fully consistent relativistic continuum random phase approximation (RCRPA) is constructed in terms of the Green's function technique. In this method the contribution of the continuum spectrum to nuclear excitations is treated exactly by the single particle Green's function, which includes also the negative states in the Dirac sea in the no sea approximation. The theoretical formalism of RCRPA and numerical details are presented. The single particle Green's function is calculated numerically by a proper product of regular and irregular solutions of the Dirac equation. The numerical details and the formalism of RCRPA in the momentum representation are presented. 相似文献
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The isoscalar giant monopole resonance (ISGMR) in nuclei is studied in the framework of a fully consistent relativistic continuum random phase approximation (RCRPA). In this method the contribution of the continuum spectrum to nuclear excitations is treated exactly by the single particle Green's function technique. The negative energy states in the Dirac sea are also included in the single particle Green's function in the no-sea approximation. The single particle Green's function is calculated numerically by a proper product of the regular and irregular solutions of the Dirac equation. The strength distributions in the RCRPA calculations, the inverse energyweighted sum rule m-1 and the centroid energy of the ISGMR in ^120Sn and ^208Pb are analysed. Numerical results of the RCRPA are checked with the constrained relativistic mean field model and relativistic random phase approximation with a discretized spectrum in the continuum. Good agreement between them is achieved. 相似文献
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Feibelman PJ 《Physical review. B, Condensed matter》1993,48(15):11270-11276
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" href="/content/?Author=M.+Castelnovo%cORF+RID%d%A%%e">M. Castelnovo " href="/content/?Author=J.-F.+Joanny%cORF+RID%d%A%%e">J.-F. Joanny 《The European physical journal. E, Soft matter》2001,6(5):377-386
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The commutative relations of the generators ofthe two-parameter deformed multimode quantum groupSLqs(3) are given, and irreducible qs-tensoroperators of rank 1/2 of the multi-mode quantum groupSLqs(2) are constructed. 相似文献
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G. Heyer P. Manakos T. Mannel T. Ohl 《Zeitschrift für Physik A Hadrons and Nuclei》1990,335(4):471-472
The Relativistic Random Phase Approximation for a meson-nucleon field theory with vector mesons is cast into an exactly soluble model. This allows to derive bounds on their couplings from consistency conditions without malting use of perturbative expansions. We find that the coupling used to fit low energy properties requires a strong suppression ofN?¯N-states by suitable cut offs. 相似文献
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In this paper, we study the evolution of a Finitary Random Interlacement (FRI) with respect to the expected length of each fiber. In contrast to the previously proved phase transition between sufficiently large and small fiber length, for all , FRI is NOT stochastically monotone as fiber length increases. At the same time, numerical evidence still strongly supports the existence and uniqueness of a critical fiber length, which is estimated theoretically and numerically to be an inversely proportional function with respect to system intensity. 相似文献
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I. N. Izosimov A. A. Solnyshkin J. H. Khushvaktov Yu. A. Vaganov 《Physics of Particles and Nuclei Letters》2018,15(3):298-309
The experimental measurement data on the fine structure of beta-decay strength function Sβ(E) in spherical, transitional, and deformed nuclei are analyzed. Modern high-resolution nuclear spectroscopy methods made it possible to identify the splitting of peaks in Sβ(E) for deformed nuclei. By analogy with splitting of the peak of E1 giant dipole resonance (GDR) in deformed nuclei, the peaks in Sβ(E) are split into two components from the axial nuclear deformation. In this report, the fine structure of Sβ(E) is discussed. Splitting of the peaks connected with the oscillations of neutrons against protons (E1GDR), of proton holes against neutrons (peaks in Sβ(E) of β+/EC-decay), and of protons against neutron holes (peaks in Sβ(E) of β–-decay) is discussed. 相似文献
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Journal of Statistical Physics - The study and analysis of real-world social, communication, information and citation networks for understanding their structure and identifying interesting patterns... 相似文献