共查询到20条相似文献,搜索用时 31 毫秒
1.
A construction procedure is derived to obtain expressions for Hamiltonian densities which characterize the bi-Hamiltonian structure of the equations in the KdV hierarchy. All results are obtained by Hamiltonizing the appropriate Lagrangian densities recently found by us. The method is seento work for both real and complex fields. 相似文献
2.
By introducing the double complex scalar field, this paper constructs the double Lagrangian with the potential V(Ф(J),Ф(J)) = V(│Ф(J)│), which not only can describe the evolution of quintom Universe, but also can naturally give the spintessence and hessence Universe. Furthermore, the U(1, J) symmetry of the double complex Lagrangian is verified, and the total conserved charge within the physical volume is derived by means of the Norther theorem. Moreover, it can point out that the 'imaginary motion' of the angular parameter in Ref.[14], in fact, is only a real phase displacement in our model. 相似文献
3.
Borut Gogala 《International Journal of Theoretical Physics》1983,22(10):887-893
The equations of the gauge theory of gravitation [Debney et al.General Relativity and Gravitation,9, 879–887 (1978)] are derived from a complex quadratic Lagrangian with torsion. The derivation is performed in a coordinate basis in a completely covariant way. 相似文献
4.
V. N. Rodionov 《Journal of Experimental and Theoretical Physics》2004,98(3):395-402
Given the anomalous magnetic moments of electrons and positrons in the one-loop approximation, we calculate the exact Lagrangian of an intense constant magnetic field that replaces the Heisenberg-Euler Lagrangian in traditional quantum electrodynamics (QED). We have established that the derived generalization of the Lagrangian is real for arbitrary magnetic fields. In a weak field, the calculated Lagrangian matches the standard Heisenberg-Euler formula. In extremely strong fields, the field dependence of the Lagrangian completely disappears and the Lagrangian tends to a constant determined by the anomalous magnetic moments of the particles. 相似文献
5.
The effective chiral Lagrangian for a matter field content consisting of pseudo-scalar Goldstone bosons and vector bosons (with hidden symmetry) is derived from the underlying QCD theory. No approximations are made. All the free parameters of the effective chiral Lagrangian are expressed in terms of QCD-based Green's functions. These may be regarded as the QCD definitions of these Lagrangian coefficients. 相似文献
6.
The effective chiral Lagrangian derived from underlying QCD for pseudo-scalar Goldstone bosons has been generalized to involve the whole nonet pseudo-Goldstone bosonk, no approximation is made in the derivation. The formulation offers general QCD definitions for the coefficients in effective chiral Lagrangian. 相似文献
7.
We analyze photoproduction of η mesons off the proton in a gauge-invariant chiral unitary framework. The interaction kernel for meson-baryon scattering is derived from the leading order chiral effective Lagrangian and iterated in a Bethe-Salpeter equation. The recent precise threshold data from the Crystal Ball at MAMI can be described rather well and the complex pole corresponding to the S11(1535) is extracted. An extension of the kernel is also discussed. 相似文献
8.
Roustam M. Zalaletdinov 《General Relativity and Gravitation》1996,28(8):953-979
The derivation of MacCallum-Taub's averaged high-frequency Lagrangian [1] is analysed with special attention paid to the assumptions made along the derivation. It is shown that averaged high-frequency Lagrangians of the same form as MacCallum-Taub's Lagrangian can be derived by applying the Brill-Hartle and macroscopic gravity averaging schemes. A procedure for the derivation of a Lagrangian of macroscopic gravity (an averaged Hilbert action) is proposed and its high-frequency limit (namely, its high-frequency perturbation expansion up to the second order terms in perturbations, which is referred to as MacCallum-Taub's limit) is calculated. There is disagreement [2] in the expressions for MacCallum-Taub's averaged high-frequency Lagrangian and the high-frequency limit of the macroscopic gravity Lagrangian. Possible reasons for such disagreement are analysed. The origin of the difference is shown to consist in using the propagation equation for perturbations, i.e. the linearized Ricci tensor vanishes, during the derivation (averaging) carried out in [1]. A new derivation of an averaged high-frequency Lagrangian without assuming the propagation equation to hold and by taking into account the proper correlation functions is given. The newly derived expression is shown to coincide with MacCallum-Taub's limit of the macroscopic gravity Lagrangian, which resolves the disagreement. 相似文献
9.
A Further Generalized Lagrangian Density and its Special Cases 总被引:1,自引:1,他引:0
Fang-Pei Chen 《International Journal of Theoretical Physics》2008,47(10):2722-2739
By summarizing and extending the Lagrangian densities of general relativity and the Kibble’s gauge theory of gravitation,a
further generalized Lagrangian density for a gravitational system is obtained and analyzed in greater detail, which will extend
the studying range for the theory of gravitation. Many special cases can be derived from this generalized Lagrangian density,
and the general characteristics and some peculiarities of them will be described and discussed. 相似文献
10.
11.
The Lagrangian and Hamiltonian formulations of electromagnetism are reviewed and the Maxwell equations are obtained from the Hamiltonian for a system of many electric charges. It is shown that three of the equations which were obtained from the Hamiltonian, namely the Lorentz force law and two Maxwell equations, can be obtained as well from a set of postulated Poisson brackets. It is shown how the results derived from these brackets can be used to reconstruct the original Lagrangian for the theory aided by some reasoning based on physical concepts. 相似文献
12.
Path and path deviation equations for neutral, charged, spinning and spinning charged test particles, using a modified Bazanski
Lagrangian, are derived. We extend this approach to strings and branes. We show how the Bazanski Lagrangian for charged point
particles and charged branes arises à la Kaluza-Klein from the Bazanski Lagrangian in 5-dimensions. 相似文献
13.
14.
Yong Zhang 《Journal of statistical physics》2010,139(5):915-939
This paper develops moment formulas for exponentially tempered, fractional advection-diffusion equations (TFADEs) that transition
from anomalous to asymptotic diffusion limits over time. Exact analytical expressions or series representations for spatial
moments up to the fourth order are derived by integral transform or asymptotic expansion approach. A fully Lagrangian solver,
cross verified by an implicit Eulerian approach, is also developed to calculate numerically the complete evolution of moments
for the TFADEs with complex initial and boundary conditions. Moment analysis identifies the diffusion equation that attracts
the tempered anomalous diffusion in the long time limit. Fitting of moments measured at two end members of alluvial systems
checks the applicability of moment analysis in understanding real diffusion. 相似文献
15.
16.
The field equations in the nonsymmetric gravitational theory are derived from a Lagrangian density using a first-order formalism. Using the general covariance of the Lagrangian density, conservation laws and tensor identities are derived. Among these are the generalized Bianchi identities and the law of energy-momentum conservation. The Lagrangian density is expanded to second-order, and treated as an Einstein plus fields theory. From this, it is deduced that the energy is positive in the radiation zone. 相似文献
17.
We study complex Lagrangian submanifolds of a compact hyper-Kähler manifold and prove two results: (a) that an involution of a hyper-Kähler manifold which is antiholomorphic with respect to one complex structure and which acts non-trivially on the corresponding symplectic form always has a fixed point locus which is complex Lagrangian with respect to one of the other complex structures, and (b) there exist Lagrangian submanifolds which are complex with respect to one complex structure and are not the fixed point locus of any involution which is anti-holomorphic with respect to one of the other complex structures. 相似文献
18.
By the generalized variational principle of two kinds of variables in general mechanics, it was demonstrated that two Lagrangian classical relationships can be applied to both holonomic systems and nonholonomic systems. And the restriction that two Lagrangian classical relationships cannot be applied to nonholonomic systems for a long time was overcome. Then, one important formula of similar Lagrangian classical relationship called the popularized Lagrangian classical relationship was derived. From Vakonomic model, by two Lagrangian classical relationships and the popularized Lagrangian classical relationship, the result is the same with Chetaev's model, and thus Chetaev's model and Vakonomic model were unified. Simultaneously, the Lagrangian theoretical framework of dynamics of nonholonomic system was established. By some representative examples, it was validated that the Lagrangian theoretical framework of dynamics of nonholonomic systems is right. 相似文献
19.
Sh. S. Agaev A. S. Vshivtsev V. Ch. Zhukovskii O. F. Semenov 《Russian Physics Journal》1985,28(1):67-69
Expressions are derived for the finite temperature effective Lagrangian for particles with spin s=0 and isospin I=1/2, 1 in an external chromomagnetic field. The difference between the Lagrangians obtained and the Euler-Heisenberg Lagrangian of QED is demonstrated.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 78–81, January, 1985. 相似文献
20.
G. B. Mainland 《Czechoslovak Journal of Physics》2005,55(9):1151-1156
Solutions are obtained to the Bethe-Salpeter equation describing bound states of two massive scalars interacting via the exchange
of a third, massive scalar. Covariance of the equation implies that the interaction is retarded, and in part because the energy
appears more than once in the equation, a Hamiltonian for the bound state does not exist. Thus in contrast to the Schrodinger
equation, the Bethe-Salpeter equation is solved by specifying the energy and solving for the coupling constant as an eigenvalue.
Although the Bethe-Salpeter equation is derived from a Lagrangian with real coupling constants, depending on the value of
the energy and the masses of the scalars, some values of the coupling constant that satisfy the Bethe-Salpeter equation are
complex and always occur in conjugate pairs. The unexpected existence of solutions with real energy and a complex coupling
constant raises the possibility that there are also resonance solutions with real values of the coupling constant and complex
energy.
Supported by a grant from the Ohio Supercomputer Center.
Presented at the 3rd International Workshop “Pseudo-Hermitian Hamiltonians in Quantum Physics”, Istanbul, Turkey, June 20–22,
2005. 相似文献