The quantum inverse scattering method approach to correlation functions

The inverse scattering method approach is developed for calculation of correlation functions in completely integrable quantum models with theR-matrix of XXX-type. These models include the one-dimensional Bose-gas and the Heisenberg XXX-model. The algebraic questions of the problem are considered.     

The inverse scattering method approach to the quantum Shabat-Mikhailov model

The Shabat-Mikhailov model is treated in the framework of the quantum inverse scattering method. The Baxter'sR-matrix for the model is calculated.     

量子可积系统和量子反散射方法简介(续)

4 .3　ＸＸＸ模型的本征值问题 ,Ｂｅｔｈｅ假设方程ｔ(ｕ)的本征值问题实际上也是Ｔ(ｕ)的本征值问题 ,它涉及到Ｔ(ｕ)的对角化问题 ,也就是说 ,对辅助空间选什么样的基矢可使Ｔ(ｕ)的表示是对角的 .1 )ＴＮ(ｕ)的矩阵元之间的对易关系在关于谐振子问题的描述中 ,我们已看到算符之间的对易关系的作用 .现在我们需要的是Ｔ(ｕ)的矩阵元之间的对易关系 ,实际上它们已经包含在ＹＢ关系中了 .前面已经指出 ,Ｔ(ｕ)相对于辅助空间为矩阵 ,这涉及到Ｖ的基矢的问题 .在Ｖ中选取自然基 :|ｅ+ 〉 =10 ,|ｅ- 〉 =01 ( 4 0 )则Ｖ Ｖ =Ｃ2 Ｃ2 中的自…     

Hubbard-like models in high spatial dimensions

The present paper studies the properties of Hubbard-like models in high spatial dimensionsD. In a first par the limit of infinite dimension and its main features-i.e.i) the mapping onto a generalized atomic model with an additional auxiliary field andii) the validity of the local approximation for the self-energy-are worked out in a systematic (1/D)-expansion. Since the hopping matrix elements have to be properly scaled with the dimensionD, the (1/D)-expansion is also an expansion in the hopping amplitude. Thus for small hopping theD-limit may serve as a proper approximation for finite-dimensional systems. The second part of the paper adopts the hybridisation-perturbation theory of the single impurity Anderson model in order to construct a perturbation theory for the auxiliary field of the generalized atom which can also be interpreted as an expansion in the hopping amplitude. The non-crossing approximation (NCA) is used to study the antiferromagnetic phase transtion of theD-Hubbard model in the case of half filling: the critical temperature, the antiferromagnetic order parameter and the free energy of the lattice system are calculated. The NCA-results are in quite good agreement with recent results from the imaginary-time discretisation method.     

A quantum version of the inverse scattering transformation

We derive a formula that expresses the local spin and field operators of fundamental graded models in terms of the elements of the monodromy matrix. This formula may be understood as a quantum version of the classical inverse scattering transformation.     

Uniqueness of inverse scattering problem in local quantum physics

It is shown that the a Bisognano-Wichmann-Unruh inspired formulation of local quantum physics which starts from wedge-localized algebras, leads to a uniqueness proof for the scattering problem. The important mathematical tool is the thermal KMS aspect of localization and its strengthening by the requirement of crossing symmetry for generalized formfactors.     

Eigenchannel method in quantum potential scattering

The eigenchannel method, generalizing the familiar phaseshift method, is formulated for scattering from a Hermitian short range potential. Scattering eigenchannels are defined as eigenstates of some generalized (weighted) operator spectral problem. Eigenvalues of that problem define eigenphaseshifts, the former being the negative of cotangents of the latter. Eigenchannel representations of generalized scattering states, transition operators, and Green operators are constructed. A variational approach to the method is also presented. The general theory is illustrated by applications to scattering of Schrödinger and Dirac particles.     

Nonstationary quantum mechanics. V. Nonstationary quantum models of scattering

Some pecularities of the results of nonstationary perturbation theory in the presence of a degenerate continuous energy spectrum are considered. Their relevance to the ideology of the preceding articles in this series is discussed.     

Quantum inverse scattering method and the Heisenberg ferromagnet

The quantum version of the inverse scattering method is formulated for the Heisenberg ferromagnet. The elements of the transition matrix for the corresponding auxiliary linear problem are the quantum analogue of the action-angle variables. In a continuous limit the model is shown to yield the quantum nonlinear Schrödinger equation.     

Grating profile reconstruction by an inverse scattering method

An inverse scattering method is used to reconstruct grating profiles from efficiency measurements. The computed profiles are compared to electron micrographs. The accuracy of the method is shown to be very good.     

A note on the inverse scattering problem in quantum field theory

We study the set of local fields describing the dynamics of a scalar, massless particle. It turns out that these fields are relatively local to the free, massless, scalar fieldA if the massless particle does not interact. This leads to a simple algebraic characterisation of interacting fields in the above framework.     

The inverse scattering problem for singular oscillating potentials

In this paper we show how to apply the Gel'fand-Levitan equations with singular oscillating potentials. We give the general procedure for solving these equations and we illustrate the method by some examples.     

On a method for solving the inverse problem in potential scattering

A method for solving the inverse problem in the non-relativistic elastic scattering theory, using the analytic and asymptotic properties of the scattering amplitude is proposed and the influence of the discontinuity parameters of the scattering amplitude on the properties of the resulting potentials is discussed. The case with spherically symmetric forces and without bound states is considered. The possibility for solving the inverse problem by this method, leading to the singular repulsive potentials is mentioned.     

A second degree Newton method for an inverse obstacle scattering problem

A regularized second degree Newton method is proposed and implemented for the inverse problem for scattering of time-harmonic acoustic waves from a sound-soft obstacle. It combines ideas due to Johansson and Sleeman [18] and Hettlich and Rundell [8] and reconstructs the obstacle from the far field pattern for scattering of one incident plane wave.     

求解DNLS方程的反散射法的基本问题

对DNLS方程, 反散射法应选取k²=p为基本谱参数, 其中k为通常谱参数. 并引入一个新的谱参数及一个规范变换, 由此得到自由Jost解的规范正交系, 这就是反散射法的基本问题. 同时还得到了基于谱参数p的Marchenko方程和Zakharov-Shabat反散射方程. 关键词： DNLS方程 反散射法 自由Jost解 规范正交系     

On relativistic-invariant formulation of the inverse scattering transform method

A manifestly relativistic-invariant formulation of the method of inverse scattering transform for relativistic-invariant equations is proposed. The sine-Gordon model and the massive Thirring model are considered.     

Factorization method for inverse obstacle scattering problem in three-dimensional planar acoustic waveguides

In this paper, we consider the inverse scattering problem of reconstructing a bounded obstacle in a three-dimensional planar waveguide from the scattered near-field data measured on a finite cylindrical surface containing the obstacle and corresponding to infinitely many incident point sources also placed on the measurement surface. The obstacle is allowed to be an impenetrable scatterer or a penetrable scatterer. We establish the validity of the factorization method with the nearfield data to characterize the obstacle in the planar waveguide by constructing an outgoing-to-incoming operator which is an integral operator defined on the measurement surface with the kernel given in terms of an infinite series.     

Finite-difference approximation for inverse scattering problem

For the first time potentials are reconstructed in a finite-difference approximation using a genuine inverse scattering method instead of multiple repeated solutions of a direct problem with iterative fitting of scattering data. Up to now a fundamental difference between spectral properties of the Schrödinger operator and its discrete analog hindered from doing this.