Darboux Transformations Of Order Research Articles

Darboux transformation of the second-type nonlocal derivative nonlinear Schrödinger equation

The second-type nonlocal derivative nonlinear Schrödinger (NDNLSII) equation is studied in this paper. By constructing its [Formula: see text]-order Darboux transformations (DT) from the first-order DT, Vandermonde-type determinant solutions of the NDNLSII equation are obtained from zero seed solutions, which would be singular unless the square of eigenvalues are purely imaginary.

Darboux transformations for differential operators on the superline

We give a full description of Darboux transformations of any order for arbitrary (nondegenerate) differential operators on the superline. We show that every Darboux transformation of such operators factorizes into elementary Darboux transformations of order one. Similar statement holds for operators on the ordinary line.

Proof of the Completeness of Darboux Wronskian Formulae for Order Two

AbstractDarboux Wronskian formulas allow us to construct Darboux transformations, but Laplace transformations, which are Darboux transformations of order one, cannot be represented this way. It has been a long-standing problem to discover what other exceptions exist. In our previous work we proved that among transformations of total order one there are no other exceptions. Here we prove that for transformations of total order two there are no exceptions at all. We also obtain a simple explicit invariant description of all possible Darboux transformations of total order two.

Higher order Darboux transformations in two dimensions, linearizable auxiliary equations, and invariant potentials

We show that the two-dimensional Schrödinger equation admits Darboux transformations only for a particular class of potentials. It is demonstrated that for such potentials, the associated auxiliary equation can be linearized to Schrödinger form. Furthermore, since the aforehand mentioned class of potentials turns out to remain invariant under Darboux transformations, construction of multiple, higher order Darboux transformations (chains) becomes possible. We present second-order chains in explicit form and give an algorithmic scheme for the construction of higher order chains.

Darboux transformations for the time-dependent nonhomogeneous Burgers equation in (1+1) dimensions

We extend the formalism of nth order Darboux transformations to the time-dependent nonhomogeneous Burgers equation (NBE) in (1+1) dimensions. Similar to the Schrödinger case, our Darboux transformation retains the form of the NBE, while changing the nonhomogeneous term. The transformed solution of the NBE and the corresponding transformed nonhomogeneity are given in closed form. Furthermore, properties of the transformation are discussed and an application is given.

Second-order Darboux displacements

The potentials for a one dimensional Schroedinger equation that are displaced along the x axis under second order Darboux transformations, called 2-SUSY invariant, are characterized in terms of a differential-difference equation. The solutions of the Schroedinger equation with such potentials are given analytically for any value of the energy. The method is illustrated by a two-soliton potential. It is proven that a particular case of the periodic Lame-Ince potential is 2-SUSY invariant. Both Bloch solutions of the corresponding Schroedinger equation equation are found for any value of the energy. A simple analytic expression for a family of two-gap potentials is derived.

Systems with higher-order shape invariance: spectral and algebraic properties

We study systems of two intertwining relations of first or second order for the same (up to a constant shift) partner Schrödinger operators. It is shown that the corresponding Hamiltonians possess a higher order shape invariance which is equivalent to the ladder equation. We analyze with particular attention irreducible second order Darboux transformations which together with the first order act as building blocks. For the third order shape-invariance irreducible Darboux transformations entail only one sequence of equidistant levels while for the reducible case the structure consists of up to three infinite sequences of equidistant levels and, in some cases, singlets or doublets of isolated levels.

Rank 2 commuting ordinary differential operators and Darboux conjugates of KdV

By considering the factorizations (flags) and associated (simultaneous) second order Darboux transformations of the square and cube of an arbitrary second order Schrödinger operator, we generate commuting ordinary differential operators of orders four and six with a singular elliptic spectrum. This procedure generates true rank 2 commutative algebras. Under the KdV flow, each such factorization (flag) leads to an integrable equation for which the corresponding Darboux transformation generates a Lax-type operator as one of a commuting pair of orders four and six with singular elliptic spectrum. Hence, these integrable equations are Darboux conjugates of KdV.