共查询到20条相似文献,搜索用时 15 毫秒
1.
Alberto Chamorro 《Pramana》1978,10(1):83-88
It is shown, by providing a general method for the construction that any Fock space linear operator defined on the dense linear
manifold spanned by the particle number representation basis can be represented in terms of the annihilation and creation
operators. The normal form of the representation is unique. 相似文献
2.
3.
Shell model calculations for the nuclei91Mo,92Tc and93Ru in the Talmi approach have been done. The ground state binding energies and the excitation spectra agree with experiment. 相似文献
4.
The effective interaction in a model space has been calculated by the Krenciglowa–Kuo (KK) and the Lee–Suzuki (LS) iterative methods, both of which assume that the unperturbed energies in the model space are degenerate. We generalize these two methods in a natural and simple manner so that they apply also to non-degenerate model spaces. The key to the generalization is to use the effective hamiltonian instead of the effective interaction in the formulation of iterative schemes. Using test calculations in a simple model, we demonstrate that the new methods work excellently. 相似文献
5.
A recursive calculational scheme is developed for matrix elements in the generalized seniority scheme for the nuclear shell model. Recurrence relations are derived which permit straightforward and efficient computation of matrix elements of one-body and two-body operators and basis state overlaps. 相似文献
6.
为了确定一种同步三通道激光告警光学系统的有效孔径并估算截获能量,建立了激光辐照远场传输模型,仿真研究了远场光斑半径、单通道入瞳半径和通道间相对能量差之间的数值关系.仿真结果表明:各通道之间最大相对能量差与远场光斑中心能量密度的大小无关,在激光远场光斑边沿处各通道之间的相对能量差最大;最大相对能量差限定时,远场光斑半径越大,允许的单通道入瞳半径也越大,但相应系统截获的脉冲能量或脉冲功率却相对减小;最大能量差限定为1%,远场光斑半径分别为2.5 m,4.0 m和7.5 m时,允许的最大单通道入瞳半径分别为3 mm, 5 mm和10 mm,相应系统截获的最大脉冲能量为1.14×10-5 J,7.54×10-6 J和2.68×10-6 J,最大脉冲功率为1.63 W, 1.08 W和0.38 W. 相似文献
7.
Helga Baum 《Journal of Geometry and Physics》1987,4(4):503-522
Let
(P) be the moduli space of irreducible connections of a G-principal bundle P over a closed Riemannian spin manifold M. Let DA be the Dirac operator of M coupled to a connection A of P and f a smooth function on M. We consider a smooth variation A(u) of A with tangent vector ω and denote Tω:=
(DA(u)−f) (u=0. The coefficients of the asymptotic expansion of trace (Tω · e-t(DA−f)2) near t=0 define 1-forms a(k)f, K=0, 1, 2, … on
(P). In this paper we calculate aa(0)f, a(1)f, a(2)f and study some of their properties. For instance using the 1-form a(2)f for suitable functions f we obtain a foliation of codimension 5 of the space of G-instantons of S4. 相似文献
8.
T. Otsuka Y. Utsuno R. Fujimoto B.A. Brown M. Honma T. Mizusaki 《The European Physical Journal A - Hadrons and Nuclei》2002,13(1-2):69-74
Two recent developments of the nuclear shell model are presented. One is a breakthrough in computational feasibility owing
to the Monte Carlo Shell Model (MCSM). By the MCSM, the structure of low-lying states can be studied with realistic interactions
for a wide, nearly unlimited basically, variety of nuclei. The magic numbers are the key concept of the shell model, and are
shown to be different in exotic nuclei from those of stable nuclei. Its novel origin and robustness will be discussed.
Received: 1 May 2001 / Accepted: 4 December 2001 相似文献
9.
A simple method, based on the Gram-Charlier expansion, to separate the smooth and fluctuating parts of the level density is
developed. Applications to spectra arising from large shell model calculations are considered. Fluctuations in the energy
levels are studied. It is found that with this proper decomposition, even long range correlations agree with the predictions
of the random matrix theory. 相似文献
10.
In this paper we discuss the nucleon pair approximation of the shell model,based on our recent results which include a brief introduction to its framework and validity.We exemplify this model by studies of low-lying states for odd-odd nuclei in the mass number A-210 region. 相似文献
11.
T. Otsuka Y. Utsuno R. Fujimoto B.A. Brown M. Honma T. Mizusaki 《The European Physical Journal A - Hadrons and Nuclei》2002,15(1-2):151-155
Two recent developments of the nuclear shell model are presented. One is a breakthrough in computational feasibility owing
to the Monte Carlo Shell Model (MCSM). By the MCSM, the structure of low-lying states can be studied with realistic interactions
for a wide, nearly unlimited basically, variety of nuclei. The magic numbers are the key concept of the shell model, and are
shown to be different in exotic nuclei from those of stable nuclei. Its novel origin and robustness will be discussed.
Received: 21 March 2002 / Accepted: 16 May 2002 / Published online: 31 October 2002
RID="a"
ID="a"e-mail: otsuka@phys.s.u-tokyo.ac.jp 相似文献
12.
A new representation of quantum mechanics involving finite difference operators is presented. The time-dependent Schrödinger wave equation is furnished as a partialdifference-differential equation. This wave equation is solved exactly for a three-dimensional oscillator.It is emphasized that this representation is exact and not a numerical approximation. 相似文献
13.
A theoretical study is given of magnon-phonon interactions in antiferromagnetic materials. The roles of magnons and phonons as heat carriers and as sources of thermal resistance have been taken into consideration. The exact collision operator which represents the magnon-phonon interactions involved in the transport Boltzmann equations has been replaced by a model operator which possesses the same important properties. The effect of other scattering processes that either phonons or magnons are involved has also been investigated. A new expression for the thermal conductivity has been derived. It includes terms which represent both Normal and Umklapp magnon-phonon processes. The results obtained by using the new expression agree quantitatively with the experimental measurements on Fe Cl2 相似文献
14.
The one body matrix elements of the effective quadrupole operator in the 2p 3/2, 1f 5/2 2p 1/2 configurations have been calculated taking into account the renormalization effects due to excitations from the closed 1f 7/2 shell. First and second order perturbations of the residual interaction as well as an infinite series involving one particle-one hole core excitations are considered. The results are used to calculate quadrupole moments of odd mass nuclei together withBE 2 values between low-lying states. Agreements with experimental results, whereever known, are seen to be generally greatly improved. 相似文献
15.
A class of clustering operators is defined which is a generalization of a transfer matrix of a Gibbs lattice field with an exponential decay of correlations. It is proved that for small values of the clustering operator has invariant subspaces which are similar tok-particle subspaces of the Fock space. The restriction of the clustering operator onto these subspaces resembles the operator exp(-H
k, whereH
k is thek- particle Schrödinger Hamiltonian in nonrelativistic quantum mechanics. The spectrum of eachH
k,k1, is contained in the interval (C
1k,C
2k). These intervals do not intersect with each other. 相似文献
16.
Y. Utsuno T. Otsuka T. Mizusaki M. Honma 《The European physical journal. Special topics》2007,150(1):187-188
Focusing on the importance of the tensor force in the effective
interaction, we investigate the structure of unstable nuclei
around N=28 with large-scale shell-model calculations.
From the analysis of the spin-tensor decomposition for
some interactions, the tensor force in the effective interaction
should be close to the π+ ρ force, whereas it is
much weaker in the Millener-Kurath (MK) interaction which is often used as the
cross-shell interaction. The significance of the tensor force
appears in the structure around 42Si: the proper tensor force
predicts that it is deformed contrary to the result from MK. 相似文献
17.
A shell model for KH2PO4 (KDP), the prototype compound of the family of H-bonded ferroelectric materials, has been constructed by adjusting the interaction parameters to first-principles calculations. Structural properties, energy barriers, phonons, and the relative stability between the ferroelectric (FE) phase and a relevant antiferroelectric metastable structure associated to domain walls, compare very favorably to available first-principles and experimental data. Molecular dynamics simulations show that the model behaves satisfactorily within the FE phase. This model will be used to study the elusive structure of the paraelectric (PE) phase and the nature of the FE–PE phase transition. 相似文献
18.
19.
We consider derivation of the effective potential for a scalar field in curved space-time within the physical regularization scheme, using two sorts of covariant cut-off regularizations. The first one is based on the local momentum representation and Riemann normal coordinates and the second is operatorial regularization, based on the Fock-Schwinger-DeWitt proper-time representation. We show, on the example of a self-interacting scalar field, that these two methods produce equal results for divergences, but the first one gives more detailed information about the finite part. Furthermore, we calculate the contribution from a massive fermion loop and discuss renormalization group equations and their interpretation for the multi-mass theories. 相似文献
20.
The microstructure and mechanical properties of white clam shell were investigated, respectively. It can be divided into horny layer, prismatic layer and nacreous layer. Crossed-lamellar structure was the microstructural characteristic. The extension direction of lamellae in prismatic layer was different from that in nacreous layer, which formed an angle on the interface between prismatic layer and nacreous layer. The phase component of three layers was CaCO3 with crystallization morphology of aragonite, which confirmed the crossed-lamellar structural characteristic. White calm shell exhibited perfect mechanical properties. The microhardness values of three layers were 273 HV, 240 HV and 300 HV, respectively. The average values of flexure and compression strength were 110.2 MPa and 80.1 MPa, respectively. The macroscopical cracks crossed the lamellae and finally terminated within the length range of about 80 μm. It was the microstructure characteristics, the angle on the interface between prismatic and nacreous layer and the hardness diversity among the different layers that enhanced mechanical properties of white calm shell. 相似文献