1,458 research outputs found

    Multichannel coupling with supersymmetric quantum mechanics and exactly-solvable model for Feshbach resonance

    Full text link
    A new type of supersymmetric transformations of the coupled-channel radial Schroedinger equation is introduced, which do not conserve the vanishing behavior of solutions at the origin. Contrary to usual transformations, these ``non-conservative'' transformations allow, in the presence of thresholds, the construction of potentials with coupled scattering matrices from uncoupled potentials. As an example, an exactly-solvable potential matrix is obtained which provides a very simple model of Feshbach-resonance phenomenon.Comment: 10 pages, 2 figure

    Method for Generating Additive Shape Invariant Potentials from an Euler Equation

    Get PDF
    In the supersymmetric quantum mechanics formalism, the shape invariance condition provides a sufficient constraint to make a quantum mechanical problem solvable; i.e., we can determine its eigenvalues and eigenfunctions algebraically. Since shape invariance relates superpotentials and their derivatives at two different values of the parameter aa, it is a non-local condition in the coordinate-parameter (x,a)(x, a) space. We transform the shape invariance condition for additive shape invariant superpotentials into two local partial differential equations. One of these equations is equivalent to the one-dimensional Euler equation expressing momentum conservation for inviscid fluid flow. The second equation provides the constraint that helps us determine unique solutions. We solve these equations to generate the set of all known \hbar-independent shape invariant superpotentials and show that there are no others. We then develop an algorithm for generating additive shape invariant superpotentials including those that depend on \hbar explicitly, and derive a new \hbar-dependent superpotential by expanding a Scarf superpotential.Comment: 1 figure, 4 tables, 18 page

    Second Order Darboux Displacements

    Full text link
    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

    Connection between the Green functions of the supersymmetric pair of Dirac Hamiltonians

    Full text link
    The Sukumar theorem about the connection between the Green functions of the supersymmetric pair of the Schr\"odinger Hamiltonians is generalized to the case of the supersymmetric pair of the Dirac Hamiltonians.Comment: 12 pages,Latex, no figure

    PT-symmetric square well and the associated SUSY hierarchies

    Full text link
    The PT-symmetric square well problem is considered in a SUSY framework. When the coupling strength ZZ lies below the critical value Z0(crit)Z_0^{\rm (crit)} where PT symmetry becomes spontaneously broken, we find a hierarchy of SUSY partner potentials, depicting an unbroken SUSY situation and reducing to the family of sec2\sec^2-like potentials in the Z0Z \to 0 limit. For ZZ above Z0(crit)Z_0^{\rm (crit)}, there is a rich diversity of SUSY hierarchies, including some with PT-symmetry breaking and some with partial PT-symmetry restoration.Comment: LaTeX, 18 pages, no figure; broken PT-symmetry case added (Sec. 6

    Supersymmetry in quantum mechanics: An extended view

    Get PDF
    The concept of supersymmetry in a quantum mechanical system is extended, permitting the recognition of many more supersymmetric systems, including very familiar ones such as the free particle. Its spectrum is shown to be supersymmetric, with space-time symmetries used for the explicit construction. No fermionic or Grassmann variables need to be invoked. Our construction extends supersymmetry to continuous spectra. Most notably, while the free particle in one dimension has generally been regarded as having a doubly degenerate continuum throughout, the construction clarifies taht there is a single zero energy state at the base of the spectrum.Comment: 4 pages, 4 figure

    Quantum Mechanics of Multi-Prong Potentials

    Get PDF
    We describe the bound state and scattering properties of a quantum mechanical particle in a scalar NN-prong potential. Such a study is of special interest since these situations are intermediate between one and two dimensions. The energy levels for the special case of NN identical prongs exhibit an alternating pattern of non-degeneracy and (N1)(N-1) fold degeneracy. It is shown that the techniques of supersymmetric quantum mechanics can be used to generate new solutions. Solutions for prongs of arbitrary lengths are developed. Discussions of tunneling in NN-well potentials and of scattering for piecewise constant potentials are given. Since our treatment is for general values of NN, the results can be studied in the large NN limit. A somewhat surprising result is that a free particle incident on an NN-prong vertex undergoes continuously increased backscattering as the number of prongs is increased.Comment: 17 pages. LATEX. On request, TOP_DRAW files or hard copies available for 7 figure

    Darboux transformations for quasi-exactly solvable Hamiltonians

    Full text link
    We construct new quasi-exactly solvable one-dimensional potentials through Darboux transformations. Three directions are investigated: Reducible and two types of irreducible second-order transformations. The irreducible transformations of the first type give singular intermediate potentials and the ones of the second type give complex-valued intermediate potentials while final potentials are meaningful in all cases. These developments are illustrated on the so-called radial sextic oscillator.Comment: 11 pages, Late
    corecore