Modern Physics Teaching

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Modern Physics

Instructor: Dr. [Sabieh Anwar] Office hours: Monday, (2-6 pm); Friday, (3-5 pm)

Teaching Fellows: [Shahid Sattar] Office hours: Wednesday(12-3 pm), Thursday(12-3 pm) and [Shama Rashid] Office hours: Monday, Tuesday and Thursday (3-5 pm)

Textbook: Quantum Physics of Atoms, Molecules, Solids, Nuclei and Particles by R. Eisberg and R. Resnick. (The book is available in the library for Rs. 1100.)


Week 1

  • Blackbody radiation
  • Spectral radiance (experimental results); Stefan's and Wien's displacement law
  • Density of modes and average energies using principle of equipartition of energy
  • Rayleigh-Jeans formula
  • Planck's correction
  • Energy is quantized!

Week 2

  • Particle nature of electromagnetic radiation
  • The photoelectric effect
  • Compton Scattering
  • What are X-rays?
  • Pair production and Pair annihilation
  • Light:particles or waves?

Week 3

  • Wave-particle duality and de Broglie relationship
  • Electron diffraction and interference (some original experiments)
  • Matter waves and wave packets
  • Relationship between position and momentum spaces and origins of Uncertainty principle

Week 4

  • Uncertainty principle (position and momentum; energy and time)
  • Atomic spectroscopy and lifetime broadening
  • Bohr's model
  • The concept of reduced mass
  • Sommerfeld and Wilson's quantization

Weeks 5 and 6

  • Motivation for the Schrodinger Equation
  • Wavefunction and its probabilistic interpretation
  • Expectation values, legitimate definition
  • Corresponding principle
  • Time independent Schrodinger Equation
  • Solving the Schrodinger Equation for a free particle



Week 7

  • Acceptable solutions of the Schrodinger Equation; legitimate wavefunctions
  • Particle in an infinite well

Week 8 (This weak is devoted to revisions and addressing misconceptions)

  • How do electrons get across nodes? Explanation This is not an easy question to answer. The simplest answer to the question is to stop thinking of the electron as a classical point particle behaving like a sphere. Rather, the best and the only way to describe the electron is through its wavefunction spread out in space. Then everything follows from there. I will discuss this further in the class.




Weeks 9 and 10

scanning tunneling microscope image of 5 nm gold nanoparticles (photograph by Dhirani)
scanning tunneling microscope image of 5 nm gold nanoparticles (photograph by Dhirani)
STM of a silicon surface, showing individual silicon atoms (photograph by IBM)
STM of a silicon surface, showing individual silicon atoms (photograph by IBM)
  • Particle in a finite well (do-it-yourself)
  • Step potential when energy is less than the potential height
  • Step potential when energy is greater than the potential height
  • Barrier potential, quantum mechanical tunneling, reflectivity and transmittivity
  • Ramseur effect, size resonance
  • Analogies with optics:
    • reflectivity from a dielectric
    • total internal reflection and evanescent waves
    • frustrated total internal reflection
  • Scanning tunneling microscopy
  • Schottky barrier
  • Field emission: metal placed in an electric field



Week 11

  • The H atom
  • Solving the three dimensional Schrodinger equation for a spherical potential
  • Origin of principal, azimuthal and orbital quantum numbers
  • orbitals: s, p, d and f
  • full derivation of spherical harmonic functions as solutions of the polar part of Schrodinger's equation

3D H atom orbital viewer



Weeks 12 and 13

  • Orbitals continued
  • Degeneracy and symmetry considerations for the free H atom
  • Radial wavefunction
  • radial probability density

Week 14

  • angular momentum in quantum mechanics
  • space quantization
  • significance of the quantum numbers, n, l and m_l




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