共查询到13条相似文献,搜索用时 0 毫秒
1.
Lie point symmetry algebras and finite transformation groups of the general Broer--Kaup system 下载免费PDF全文
Using a new symmetry group theory, the transformation groups and
symmetries of the general Broer--Kaup system are obtained. The
results are much simpler than those obtained via the standard
approaches. 相似文献
2.
In this paper, the Lie symmetry algebra of the coupled
Kadomtsev--Petviashvili (cKP) equation is obtained by the classical Lie group method and
this algebra is shown to have
a Kac--Moody--Virasoro loop algebra structure. Then the general symmetry groups of the cKP
equation is also obtained by the symmetry group direct method which is proposed by Lou et al。 From the
general symmetry groups, the Lie symmetry group can be recovered and a group
of discrete transformations can be derived simultaneously. Lastly,
from a known simple solution of the cKP equation, we can easily obtain
two new solutions by the general symmetry groups. 相似文献
3.
K Rama Mohana Rao 《Pramana》1990,35(2):141-149
A flow chart (inverted ‘tree’) for generating and identifying the 58 magnetic and 18 polychromatic point groups using a classification
for the 32 generating crystallographic point groups is suggested. The idea of colour generator is explored for generating
the colour symmetry point groups. The advantages in presenting the identification of colour groups through a tree are discussed. 相似文献
4.
5.
Surface harmonics for the seven pentagonal point groups 5(C5), {ie859-1}(S10), {ie859-2}(C5h
), {ie859-3}m2(D5h
), {ie859-4} 2(D5), 5m(C5v
) and 5 2m(D5d
) that represent the symmetries of quasicrystals in two and three dimensions are obtained, employing the projection operator
method [11] and the simplified (authors) method. The results obtained are tabulated and are briefly discussed. 相似文献
6.
J. L. Rubin 《Il Nuovo Cimento D》1993,15(1):59-72
Summary A connection between the creation of toroidal moments and the breaking of the relativistic crystalline group associated to
a given crystal is presented in this paper. Indeed, if magnetoelectric effects exist, the interaction between electrons and
elementary magnetic cells appears in such a way that the resulting local polarization and magnetization break the local relativistic
crystalline symmetry. Therefore, a Goldstone boson responsible for the production of toroidal moments is created and, consequently
toroidal phases arise in the crystal. The list of the Shubnikov groups compatible with this kind of phases is given and possible
consequences in superconductor theory in magnetoelectric crystals are examined. 相似文献
7.
8.
New infinite-dimensional symmetry groups for the stationary axisymmetric Einstein--Maxwell equations
with multiple Abelian gauge fields 下载免费PDF全文
The so-called extended hyperbolic complex (EHC) function method
is used to study further the stationary axisymmetric Einstein--Maxwell theory with
$p$ Abelian gauge fields (EM-$p$ theory, for short). Two EHC structural
Riemann--Hilbert (RH) transformations are constructed and are then shown to give
an infinite-dimensional symmetry group of the EM-$p$ theory. This symmetry group is
verified to have the structure of semidirect product of Kac--Moody group
$\widehat{SU(p+1,1)}$ and Virasoro group. Moreover, the infinitesimal
forms of these
two RH transformations are calculated and found to give exactly the same
infinitesimal transformations as in previous author's paper
by a different scheme. This demonstrates that the results
obtained in the present paper provide some exponentiations of all the infinitesimal
symmetry transformations obtained before. 相似文献
9.
10.
Group-theoretical methods have been accepted as exact and reliable tools in studying the physical properties of crystals and
quasicrystalline materials. By group representation theory, the maximum number of non-vanishing and independent second-order
piezoelectric coefficients required by the seven pentagonal and two icosahedral point groups — that describe the quasicrystal
symmetry groups in two and three dimensions — is determined. The schemes of non-vanishing and independent second-order piezoelectric
tensor components needed by the nine point groups with five-fold rotations are identified and tabulated employing a compact
notation. The results of this group-theoretical study are briefly discussed.
相似文献
11.
In this Letter we try to settle some confused points concerning the use of the notion of p-nuclearity in the mathematical and physical literature, pointing out that the nuclearity index in the physicists’ sense vanishes for any p> 1. Our discussion of these issues suggests a new perspective, in terms of ε-entropy and operator spaces, which might permit connections to be drawn between phase space criteria and quantum energy inequalities.Mathematics Subject Classification (2000): 81T05, 47B10, 47L25. 相似文献
12.
R E Marshak 《Pramana》1988,31(1):9-39
This retrospective paper traces the conceptual evolution of two theories in which the author was involved—the two-meson theory
(with H A Bethe) in 1947 and the universal (V-A) theory of weak interactions (with E C G Sudarshan) in 1957—into the present-day standard model of particle interactions.
Part 1 is entitled ‘From the pion to QCD and pseudo-Goldstone bosons” and Part 2 “From the muon and neutrino to QFD and chiral
anomalies’.
Adapted from two lectures delivered at the University of Rochester in October, 1987. 相似文献
13.
Nobuaki Kanamaru 《Journal of Molecular Spectroscopy》2004,225(1):55-61
The title subjects (in the vapor phase) were assessed to be in the weak-coupling limit as Frenkel-type excitons of a La-type excited state, by examining reported data on these systems: (1) Lb/La interconversion by dimerization (in the solution) just like what happens in the monomer by the change of solvent polarity, e.g., from 3-methylpentane to ethanol. (2) Good correspondence between the monophotonic excitation spectrum of the tautomer fluorescence (after excited-state double proton-transfer reaction of the dimer) and mass-selected (2 + 2) photoionization spectrum of the dimer, as is predicted theoretically. (3) Potential minima for locally excited configurations, as were predicted by ab initio calculations. Comments on the current controversy about the mechanism of its excited-state tautomerization, i.e., whether it is of one step or two steps, are made as well. 相似文献