The structure of11Be

More than twenty experimental level data of nuclei far from β-stability are selected to determine new effective parameters for the Modified Surface Delta Interaction and for the single particle energies. With these parameters used in the calculation for 1p-shell nuclei far from β-stability, the agreement between computed results and experimental data becomes fair, and the parity inversion for the 1/2⁺ ground state in¹¹Be is correctly reproduced. The structure of¹¹Be is discussed in some detail.     

The Novel Cluster States in 10Be

We have investigated the cluster structures in ¹⁰Be by using ⁶He+α cluster wave functions and dineutron condensate wave functions. We suggested two kinds of exotic cluster states which have not been confirmed experimentally yet. One of them has a gas-like structure of two alphas and one dineutron, and another has ⁶He and an extremely developed α.     

The NN interaction in a quark model with quark-antiquark excitations

Quark-antiquark excitations inherent in the quark-gluon interaction have been incorporated into a quark model of the nucleon to study the effects of such excitations on the NN interaction within the framework of the resonating group method. The three-quark (3q) components of a single nucleon are augmented by ($\text{3}\text{q}\text{)(}\text{q}\text{q}$) excitations with the 24 possible spin, isospin, color combinations for the energetically lowest p-wave relative motion function. Quark exchange kernels are then calculated for the two-nucleon system described by these improved nucleon internal functions; and these exchange kernels are converted to phase-shift-equivalent effective NN potentials by the Wigner-transform WKB technique. The off-shell qq? pair-creation terms are derived from the one-gluon exchange diagrams in the Breit approximation in analogy with the derivation of the qq and qq? potentials. The parameters of the interaction are chosen to be consistent with the experimental Δ-N mass difference, the nucleon-vector-meson coupling constants, and the nucleon magnetic moments. Within these constraints, the predicted amplitudes of the ($\text{3}\text{q}\text{)(}\text{q}\text{q}$) components of the nucleon internal functions have been shown to be insensitive to the precise values of the model parameters. In particular, they pass the crucial test of being insensitive to very large changes in the magnitude of the confinement potential constant which is a necessary ingredient of the model. The qq? excitations lead to the following effects in the S-wave NN potentials: (i) The repulsive core heights of the simple 3q-3q model are greatly reduced but retain their strong essentially linear energy dependence, with numerical values very similar to those of the short-range phenomenological terms of the Paris potential. (ii) The effective potentials have acquired an attractive part in the 0.8-1.5 fm range. However, this attraction is too weak to bind the deuteron or fit the extreme low-energy S-wave phase shifts.     

The dynamic characters of excitations in aone-dimensional Frenkel--Kontorova model

A one-dimensional （1D） Frenkel-Kontorova （FK） model is studied numerically in this paper, and two new analytical solutions （a supersonic kink and a nonlinear periodic wave） of the Sine-Gordon （SG） equation （continuum limit approximation of the FK model） are obtained by using the Jacobi elliptic function expansion method. Taking these new solutions as initial conditions for the FK model, we numerically find there exist the supersonic kink and the nonlinear periodic wave in these systems and obtain a lot of interesting and significant results. Moreover, we also investigate the subsonic kink and the breather in these systems and obtain some new feature.     

Highly excited 8Be core in the configuration of the 12C and 11B ground states

Angular distributions of the ¹²C(d, ⁶Li)⁸Be reaction at E_lab = 78.0 MeV and the ¹¹B(³He, ⁶Li)⁸Be reaction at E_lab = 71.8 MeV were measured. Transitions leading to ⁸Be in the ground state and the 3.04, 16.63, 16.92, 17.64 and 18.15 MeV excited states were observed. A DWBA analysis was performed regarding the (d, ⁶Li) and (³He, ⁶Li) reactions as direct α particle or triton transfers, respectively.     

Interaction of conduction electrons with local excitations. The infrared divergencies

Using the renormalization group method the higher orders of perturbation theory in the interaction of conduction electrons in metals with local paulions (pseudospins), e.g. two-level systems, crystal-field excitations, and bosons, e.g. phonons, are considered. For the paulions, the lowest order logarithmic singularities in the electron self-energy at =E–E _F±, being the splitting, become weaker, at least in the commutative model. It is shown that the singularities of the type ln are absent. This justifies the applicability of the second order perturbation theory resultm ^{* –1} for the electron effective mass even atm ^*m. For the phonons, the singularities at ±₀, ₀ being the phonon frequency, may become stronger or weaker depending on the conduction band filling and the anharmonic contribution to the deformation potential. The singular contributions to the local excitation Green's function are calculated. They result in the change of the line shape of the local level (the orthogonality catastrophe). The singular terms in the ground state energy and average pseudospin are considered.     

Field theory of collective excitations; I. A soluble model

Collective fields are introduced into fermion Lagrangians and graphical rules for a joint treatment of both types of excitations are derived via Feynman path integrals. For the soluble degenerate-shell model with pairing forces used in nuclear and many-body physics the exact collective action is exhibited.     

太阳核心存在三价铍7离子的计算

计算表明在太阳核心从R=0至R=0.125R⊙之间,存在三价铍7离子数几乎为零.重新计算的铍7太阳中微子和硼8太阳中微子流量要比标准太阳模型分别降低1.2倍和增加1.2倍.     

Double folding model analysis of elastic scattering of halo nucleus 11Be from 64Zn

Calculations of elastic scattering cross-sections for ^9,10,11Be + ⁶⁴Zn at near-Coulomb barrier energy have been performed using a potential obtained from the double folding model and are compared with the experiment. In the framework of the double folding model, the nuclear matter densities of ^9,10,11Be projectiles and a ⁶⁴Zn target are folded with the complex energy-dependent effective M3Y interaction. The angular distributions of the differential cross-section for ^9,10Be scattering from ⁶⁴Zn at E _c.m≈ 24.5 MeV agree remarkably well with the data, while in case of ¹¹Be, calculations show a Coulomb–nuclear interference peak which is not observed in the data.     

Influence of core excitations on the deuteron stripping reaction with the method of many-body green functions

Within the scope of many-body Green functions we derive a formally exact expression for the (d,p)-stripping amplitude, which resembles the DWBA for this reaction. However, the distorted wavefunctions in the entrance and exit channel are defined with respect to the most general expressions for the optical potentials, as they are given by the mass operators of corresponding Dyson equations for correlation functions. In the same way the transition operator is a complicated many-body quantity which explicitly depends on the deuteron energy and contains for example contributions coming from the core excitations of the target nucleus. In this paper we are mainly interested in the latter effect and a numerical estimation of a crude model for the many-body effects of the transition operator reveals no pronounced (sharply resonant) energy dependence. The essential difference of our paper to other publications on the same subject is that we are dealing with the “Dyson equation” approach developed recently for higher Green functions.     

NN tensor and LS potentials in a quark model with quark-antiquark excitations

A more detailed study is made of the NN interaction in a quark model in which the (qq̄) excitations inherent in the quark-gluon interaction are explicitly incorporated into the model space. A unified treatment for all types of exchange terms of the (3q)-(3q) to (3q)-(3q)(qq̄) coupling kernels is used to calculate the space parts of the full coupling kernels and their Wigner transforms in complete analytic form. The present investigation focuses on the noncentral parts of the NN interaction. The tensor force gains almost its full strength from coupling kernels of Nπ and Nρ type. If the Nπ contribution is adjusted to fit the experimental pion-nucleon coupling constant the predicted strength of the full tensor force is in reasonable agreement with that of conventional OBEP's over the range in which the tensor force can act. The LS force gains contributions from both the pure (3q)-(3q) and the coupling kernels, but the dominant contributions (about 60–65% of the triplet-odd LS potential in the 0.7–1.0 fm range), come from the coupling kernels and particularly from the Nω and Nρ components. The triplet-odd LS potential derived from the full quark-exchange kernel is in remarkably good agreement with the OBEP LS potential over the significant range. Both the tensor and LS potentials are approximated surprisingly well over their full range by the simple (qq̄) exchange terms of our model. The ³P RGM phase shifts are calculated to show that both tensor and LS forces of our quark model are in good agreement with the experimental facts.     

The probability of MgO surface excitations with fast electrons

A scanning Transmission Electron Microscope has been used to investigate the probability of exciting surface modes in MgO cubes when fast electrons pass a certain distance outside the specimen. The experimental results give reasonable agreement with the classical theory of dielectric excitation by a moving charge providing relativistic effects are included.     

Cluster fermionic Ising spin glass model with a transverse field

The fermionic Ising spin glass (SG) model in the presence of a transverse magnetic field Γ is studied within a cluster mean field theory. The model considers an infinite-range interaction among magnetic moments of clusters with a short-range ferromagnetic intracluster coupling J₀. The spin operators are written as a bilinear combination of fermionic operators. In this quantum SG model, the intercluster disorder is treated by using a framework of one-step replica symmetry breaking (RSB) within the static approximation. The effective intracluster interaction is then computed by means of an exact diagonalization method. Results for several values of cluster size n_s, Γ and J₀ are presented. For instance, the specific heat can show a broad maximum at a temperature T^∗ above the freezing temperature T_f, which is characterized by the intercluster RSB. The difference between T^∗ and T_f is enhanced by Γ, which suggests that the quantum effects can increase the ratio T^∗/T_f. Phase diagrams (T versus Γ) show that the critical temperature T_f(Γ) decreases for any values of n_s and J₀ when Γ increases until it reaches a quantum critical point at some value of Γ_c.     

Magnetic model for a horse-spleen ferritin with a three-phase core structure

The increasing interests in magnetic nanoparticles has prompted research on ferritin, which is naturally a well-defined iron-storage protein in most living organisms. However, the exact magnetic behavior of ferritin is not well understood, because the crystal structures of ferritin and ferrihydrite, its major component, are not fully understood. Briefly, we discuss the previous magnetization models of ferritin and ferrihydrite and we present a new model (Σ3L) of the initial magnetization of ferritin, considering its different phases. The new model includes three Langevin-function terms, which represent three different magnetic moments provided by the likely hydroxide and oxide mineral phases in ferritin. Compared to previous models, our simple model fits the experimental data 12 times better in terms of the sum of least squares. The magnetic independence of each component supports the multi-phase compositional model of the mineral core of horse-spleen ferritin. This Σ3L model gives a quantization of the amounts of the different phases within horse-spleen ferritins that matches other published experimental data: 60-80% ferrihydrite, 15-25% maghemite/magnetite, and 1-10% hematite.