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Dive into the fascinating world of Quantum Mechanics with an exploration of the double slit experiment, particle motion, eigenstates, eigenvalues, and dynamics. Understand complex numbers visualization, free particles, boundary conditions, harmonic oscillators, scattering, and tunneling phenomena. Unravel the mysteries of eigenfunctions, quantum particles in potential wells, and computational methods for analyzing quantum systems. Engage with interactive programs and applets to deepen your understanding of quantum concepts.
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Visual Quantum Mechanics Hans-Jürgen Korsch Fachbereich Physik TU Kaiserslautern
Outline • The Quantum Double Slit experiment • Motion of Quantum Wave Packets • Eigenstates & Eigenvalues • Eigenstates & Dynamics
Quantum Double Slit Experiment I One of the major paradoxes that we use to introduce Quantum Mechanics is the double slit experiment for classical particles, classical waves and quantum objects. bullets
Quantum Double Slit Experiment II Particles: `bullets´ Waves:
Quantum Double Slit Experiment III Quantum particles (electrons): after 10 electrons after 25 electrons Only single electrons are emitted !!! after 100 electrons after 1000 electrons
Outline • The Quantum Double Slit experiment • Motion of Quantum Wave Packets • Eigenstates & Eigenvalues • Eigenstates & Dynamics
Motion of Quantum Wave Packets • Visualization of complex numbers • Free particles • Boundary conditions • Harmonic oscillator • Scattering – tunneling and STM Programs from the book „Visual Quantum Mechanics“ by Bernd Thaller http://www.kfunigraz.ac.at/imawww/vqm/
Outline • The Quantum Double Slit experiment • Motion of Quantum Wave Packets • Eigenstates & Eigenvalues • Eigenstates & Dynamics
The are determined by the wavefunction at time Eigenstates & Eigenvalues I • Hamiltonian • Eigenfunctions • General solution `phasor´
Eigenstates & Eigenvalues II • Hamiltonian • eigenvalues • eigenfunctions Hermite functions
Eigenstates & Eigenvalues III • matrix representation of operators • matrix elements
Eigenstates & Eigenvalues IV • quantum particle in a potential V(x): • Hamiltonian • matrix representation of position and momentum : • matrix representation of H
Eigenstates & Eigenvalues V Computational recipe: • represent x and p by (nxn)-matrices (n large) • evaluate matrix H(x,p) • compute eigenvalues of matrix H simple numerical method for computation of eigenvalues and eigenfunctions
Matlab Program– eigen.m - % position and momentum operator % represented in HO-eigenfunctions n=1:99; m=sqrt(n); aminus = diag(m,1); aplus = diag(m,-1); x= 1/sqrt(2)*(aminus + aplus); p=-i/sqrt(2)*(aminus - aplus); % Hamilton operator H1=0.5*p^2+0.5*x^2; % computation of eigenvalues [V,D] = eig(H1); [E,index] = sort(diag(D)); eigenvalues=E(1:10)
Outline • The Quantum Double Slit experiment • Motion of Quantum Wave Packets • Eigenstates & Eigenvalues • Eigenstates & Dynamics
Eigenstates & Dynamics eigenfunctions & wavefuction dynamics for several exactly solvable potentials • 1D: box potential • double well • harmonic oscillator • 2D: box potential • harmonic oscillator • 3D: hydrogen atom Applets written by Paul Falstad http://www.falstad.com/mathphysics.html