Algebraic Method of Solution of Schrödinger’s Equation ofa Quantum Model (original) (raw)

A General Approach for the Exact Solution of the Schrödinger Equation

International Journal of Theoretical Physics, 2009

The Schrödinger equation is solved exactly for some well known potentials. Solutions are obtained reducing the Schrödinger equation into a second order differential equation by using an appropriate coordinate transformation. The Nikiforov-Uvarov method is used in the calculations to get energy eigenvalues and the corresponding wave functions.

A new derivation of the time-dependent Schr�dinger equation from wave and matrix mechanics

Physics Essays, 2016

An alternative method is proposed for deriving the time-dependent Schrödinger equation from the pictures of wave and matrix mechanics. The derivation is of a mixed classical-quantum character, since time is treated as a classical variable, thus avoiding any controversy over its meaning in quantum mechanics. The derivation method proposed in this paper requires no ad hoc assumption and avoids going through a second-order differential equation that can be reduced to the well-known time-dependent Schrödinger equation only postulating a complex wavefunction with a time dependence given by (− / ), as did by Schrödinger in its original paper of 1926 [1].

Phase-space matrix representation of differential equations for obtaining the energy spectrum of model quantum systems

2021

Employing the phase-space representation of second order ordinary differential equations we developed a method to find the eigenvalues and eigenfunctions of the 1dimensional time independent Schrödinger equation for quantum model systems. The method presented simplifies some approaches shown in textbooks, based on asymptotic analyses of the time-independent Schrödinger equation, and power series methods with recurrence relations. In addition, the method presented here facilitates the understanding of the relationship between the ordinary differential equations of the mathematical physics and the time independent Schrödinger equation of physical models as the harmonic oscillator, the rigid rotor, the Hydrogen atom, and the Morse oscillator.

A New Derivation of the Time-Dependent Schrödinger Equation from Wave and Matrix Mechanics

An alternative method is proposed for deriving the time-dependent Schrödinger equation from the pictures of wave and matrix mechanics. The derivation is of a mixed classical–quantum character, since time is treated as a classical variable, thus avoiding any controversy over its meaning in quantum mechanics. The derivation method proposed in this paper requires no ad hoc assumption and avoids going through a second-order differential equation that can be reduced to the well-known time-dependent Schrödinger equation only postulating a complex wavefunction with a time dependence given by 𝑒𝑥𝑝(−𝑖𝐸𝑡/ ), as did by Schrödinger in its original paper of 1926

Analyzing the Time Evolution of Wave Functions by Decomposing the Hamiltonian into State-Preserving and State-Changing Hamiltonians

arXiv: Quantum Physics, 2014

We show a new method for analyzing the time evolution of the Schrodinger wave function Psi(x,t). We propose the decomposition of the Hamiltonian as: H(t)=Hp(t)+Hc(t), where Hp(t) is the Hamiltonian such that Psi(x,t) is its instantaneous eigenfunction, and Hc(t) the Hamiltonian which changes the state Psi. With this decomposition, the action of H(t) on the wave function is simplified and the Schrodinger equation is in a simpler form which can be solved more easily. We illustrate this method by exactly solving the Schrodinger equation for cases of nonspreading wave packets. This method can be applied as well to analyzing the time evolution of general Hamiltonian systems.

Exact solution of generalized Tavis - Cummings models in quantum optics

Journal of Physics A: Mathematical and General, 1996

Quantum inverse methods are developed for the exact solution of models which describe N two-level atoms interacting with one mode of the quantized electromagnetic field containing an arbitrary number of excitations M. Either a Kerr-type nonlinearity or a Stark-shift term can be included in the model, and it is shown that these two cases can be mapped from one to the other. The method of solution provides a general framework within which many related problems can similarly be solved. Explicit formulae are given for the Rabi splitting of the models for some N and M, on-and off-resonance. It is also shown that the solution of the pure Tavis-Cummings model can be reduced to solving a homogeneous ordinary differential equation of second order. Generalization of the method to the case of several cavity modes is indicated.

Numerical Modelling of Some Quantum Systems

Quantum mechanics, like classical mechanics, can be formulated and analyzed in many different ways. Some of these approaches are reviewed in this thesis, to some extent from the viewpoint of how a formulation can be modelled and solved numerically. In this thesis the numerical simulation of two problems is studied.

On Hamiltonian Formulations of the Schrödinger System

Annals of Physics, 2002

We review and compare different variational formulations for the Schrödinger field. Some of them rely on the addition of a conveniently chosen total time derivative to the hermitic Lagrangian. Alternatively, the Dirac-Bergmann algorithm yields the Schrödinger equation first as a consistency condition in the full phase space, second as canonical equation in the reduced phase space. The two methods lead to the same (reduced) Hamiltonian. As a third possibility, the Faddeev-Jackiw method is shown to be a shortcut of the Dirac method. By implementing the quantization scheme for systems with second class constraints, inconsistencies of previous treatments are eliminated.

The solution of the time dependent Schrödinger equation by the (t,t’) method: The use of global polynomial propagators for time dependent Hamiltonians

Journal of Chemical Physics, 1994

Using the (f,t ') method as introduced in Ref. 1 [J. Chem. Phys. 99, 4590 (1993)] computational techniques which originally were developed for time independent Harniltonians can be used for propagating an initial state for explicitly time dependent Hamiltonians. The present paper presents a time dependent integrator of the Schrodinger equation based on a Chebychev expansion, of the operator U(x,t ' ,tO+t), and the Fourier pseudospectral method for calculating spatial derivatives [ (d2/dx2), (a/&')]. Illustrative numerical examples for harmonic and Morse oscillators interacting with CW and short pulsed laser fields are given.

A simple method to construct eigenset of single-active-electron atom in momentum space with applications to solve time-dependent Schroedinger equation

arXiv: Quantum Physics, 2017

We present a highly accurate method for solving single-active-electron (SAE) atomic eigenset in momentum space. The trouble of Coulomb kernel singularity is bypassed with numerical quadrature, which is simple but effective. The complicated Lande regularization method is no longer necessary. The data of accuracy for some low-lying states of the hydrogen and SAE helium atom were tabulated. Two examples of using the generated eigenset to solve the hydrogen atom under strong-field laser pulses were shown. The momentum and the coordinate representation are complementary to each other in quantum mechanics. The simple method to generate eigenstates and the localized behavior of wave functions in momentum space would be useful in the study of quantum mechanical problems involving continuous states.