107 research outputs found
Giant magnetothermal conductivity and magnetostriction effect in charge ordered NdNaMnO compound
We present results on resistivity (), magnetization (), thermal
conductivity (), magnetostriction () and
specific heat () of charge-orbital ordered antiferromagnetic
NdNaMnO compound. Magnetic field-induced
antiferromagnetic/charge-orbital ordered insulating to ferromagnetic metallic
transition leads to giant magnetothermal conductivity and magnetostriction
effect. The low-temperature irreversibility behavior in , ,
and due to field cycling together with striking
similarity among the field and temperature dependence of these parameters
manifest the presence of strong and complex spin-charge-lattice coupling in
this compound. The giant magnetothermal conductivity is attributed mainly to
the suppression of phonon scattering due to the destabilization of spin
fluctuations and static/dynamic Jahn-Teller distortion by the application of
magnetic field.Comment: 4 Pages, 4 Figure
Exactly solvable Wadati potentials in the PT-symmetric Gross-Pitaevskii equation
This note examines Gross-Pitaevskii equations with PT-symmetric potentials of
the Wadati type: . We formulate a recipe for the construction of
Wadati potentials supporting exact localised solutions. The general procedure
is exemplified by equations with attractive and repulsive cubic nonlinearity
bearing a variety of bright and dark solitons.Comment: To appear in Proceedings of the 15 Conference on Pseudo-Hermitian
Hamiltonians in Quantum Physics, May 18-23 2015, Palermo, Italy (Springer
Proceedings in Physics, 2016
Supersymmetry Across Nanoscale Heterojunction
We argue that supersymmetric transformation could be applied across the
heterojunction formed by joining of two mixed semiconductors. A general
framework is described by specifying the structure of ladder operators at the
junction for making quantitative estimation of physical quantities. For a
particular heterojunction device, we show that an exponential grading inside a
nanoscale doped layer is amenable to exact analytical treatment for a class of
potentials distorted by the junctions through the solutions of transformed
Morse-Type potentials.Comment: 7 pages, 2 figure
Non-isospectrality of the generalized Swanson Hamiltonian and harmonic oscillator
The generalized Swanson Hamiltonian with , can be transformed into an equivalent Hermitian Hamiltonian
with the help of a similarity transformation. It is shown that the equivalent
Hermitian Hamiltonian can be further transformed into the harmonic oscillator
Hamiltonian so long as constant. However, the
main objective of this paper is to show that though the commutator of
and is constant, the generalized Swanson
Hamiltonian is not necessarily isospectral to the harmonic oscillator. Reason
for this anomaly is discussed in the frame work of position dependent mass
models by choosing as the inverse square root of the mass function.Comment: Accepted in Journal of Physics A. Comments are welcom
Nonsingular potentials from excited state factorization of a quantum system with position dependent mass
The modified factorization technique of a quantum system characterized by
position-dependent mass Hamiltonian is presented. It has been shown that the
singular superpotential defined in terms of a mass function and a excited state
wave function of a given position-dependent mass Hamiltonian can be used to
construct non-singular isospectral Hamiltonians. The method has been
illustrated with the help of a few examples.Comment: Improved version accepted in J. Phys.
Coherent state of a nonlinear oscillator and its revival dynamics
The coherent state of a nonlinear oscillator having a nonlinear spectrum is
constructed using Gazeau Klauder formalism. The weighting distribution and the
Mandel parameter are studied. Details of the revival structure arising from
different time scales underlying the quadratic energy spectrum are investigated
by the phase analysis of the autocorrelation function
A generalized quantum nonlinear oscillator
We examine various generalizations, e.g. exactly solvable, quasi-exactly
solvable and non-Hermitian variants, of a quantum nonlinear oscillator. For all
these cases, the same mass function has been used and it has also been shown
that the new exactly solvable potentials possess shape invariance symmetry. The
solutions are obtained in terms of classical orthogonal polynomials
Exceptional orthogonal polynomials and exactly solvable potentials in position dependent mass Schroedinger Hamiltonians
Some exactly solvable potentials in the position dependent mass background
are generated whose bound states are given in terms of Laguerre- or Jacobi-type
exceptional orthogonal polynomials. These potentials are shown to be
shape invariant and isospectral to the potentials whose bound state solutions
involve classical Laguerre or Jacobi polynomials.Comment: To appear in Physics Letters
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