Modern Physics Teaching Spring2013

Current revision

Modern Physics (with thermodynamics)

Instructor: Dr. [Sabieh Anwar] Office hours: Tuesday and Thursday, (11:15 am to 1 pm). Recitation instructors are Dr. [Ata-ul-Haq] and Dr. [Imran Younus].

Teaching Instructors: [Shama Rashid],[Mudassir Moosa], [Syeda Qurrat-ul-Ain Akbar], [Maryam Khaqan], [Faran Irshad], [Hasnain Ali Pirzada]. Office hours and tutorial schedule is here.

Textbooks: Modern Physics by R.A. Serway, C.J. Moses and C.A. Moyer (also available in low priced edition.)

Course outline: Click here for the course outline.

Previous offerings: Here is the weblink for the same course I taught in Fall 2009. You will find homeworks, exams and their solutions from the 2009 offering of this course here, all in a consolidated pdf. Errors and omissions are expected. And here is the weblink for the offering in 2011 with all the video recordings.

Pre-mid term

Most important experiment in physics (1 lecture)

• Double-slit experiment with bullets, waves and electrons
• Spying on the electron to obtain "which-way" information erases the interference pattern
• Reading material: Quantum behavior from Vol.3 of Feynman's Lecture Notes on Physics.

Internal energy and its quantization (9 lectures)

Visit the demonstrations page for links to demos shown in class.

Field emission - glowing tube light in high tension

• harmonic oscillator
• concept of internal energy
• thermal energy and temperature
• first law of thermodynamics
• internal energy is quantized
• Line and continuous spectra
• Quantization of vibrational levels and role of temperature
• Quantization of rotational levels and microwave heating
• Excitation by electron impact - Franck-Hertz experiment
• Boltzmann factor

Recitation, tutorial material and reading suggestions:

• Recitation 1.1: deals with the solution of second order differential equations
• Recitation 1.2: dealing wiith quantized levels and first law of thermodynamics
• Tutorial 1.1: on energy quantization and Boltzmann factor
• Recitation 1.3: on energy loss, rotational and vibrational spectroscopy
• Physics for Scientists and Engineers, by Serway and Jewett, Sections: 20.1, 20.4, 20.5, 20.6, 21.4, 21.5, 221., 22.3, 22.6, 22.7, 22.8. This reading material has been uploaded to LMS.

Note: Microsoft Silverlight (a freeware) is required to view the videos.

Video recordings:

Introducing internal energy: [1]

First law of thermodynamics and concept of the photon: [2]

Quantized energy levels and demonstrations on spectroscopy: [3]

Emission and absorption of photons, quantum harmonic oscillator: [4]

Franck-Hertz, micro-lightning, rotational and vibrational levels (part A): [5]

part B: [6]

Boltzmann distribution: [7]

Second law of thermodynamics (4 lectures)

Entropy can be created.

• microstates and macrostates
• fundamental premises of statistical mechanics: all microstates are equally probable
• distribution of energy in solids
• entropy and the second law of thermodynamics
• alternative meaning of temperature
• examples

Recitation, tutorial material and reading suggestions:

• Introduction to Thermal Physics, by D.V. Schroeder, Chapter 2. It has been added to LMS.
• Simulations on entropy in energy exchange between two solids. (This is a Matlab script written by Sabieh Anwar.)
• Simulations on entropy and temperature. (Another Matlab script.)
• Recitation 2.1: dealing with microstates, macrostates, entropy, second law of thermodynamics.
• Tutorial 2.1: more examples with microstates, macrostates, entropy, second law of thermodynamics
• Recitation 2.2: deals with entropy and its computation, approach towards equilibrium.
• Tutorial 2.2: on the entropy of expansion and mixing

Homework 1: (on thermodynamics)

• Download the homework. Deadline is Monday 4 March, 2013.

Video recordings:

Macrostates, microstates and distribution of energies: [8]

Entropy and second law of thermodynamics: [9]

Entropy and temperature: [10]

Wrapping it up: energy, entropy, temperature and its computation: [11]

Modern version of J.J. Thomson's experiment

Video recordings:

Atom and discovery of the electron: [12]

Modern version of Thomson's experiment and Rutherford's nucleus [13]

Bohr's ideas [14]

What are waves [15].

Building wavepackets (part A) [16]

Building wavepackets and Fourier inetgral(part B) [17]

Phase and group velocity, dispersion and demos on diffraction [18]

Particle description of radiation (4 lectures) Photoelectric effect X-rays and X-ray fluorescence Compton effect Positron emission tomography Read Ch 3 of Serway's Modern Physics book. For characteristic X-rays, you may also read Section 9.7 of Serway's book. Here is my presentation on some interesting signposts in the history of X-rays. Recitation 3.3: on the Compton Effect.

X-ray fluorescence and Moseley's law

Spectrum of steel was shown in class.

Video recordings:

Problems with a classical description of the photoelectric effect: [19]

Describing the photoelectric effect and X-rays: [20]

One video lecture is not available, due to a technical fault.

Compton Effect: [21]

Post-mid term

Matter waves and wave particle duality (10 lectures)

Electrons are in fact diffracted

• Nature of photon? particle or wave?
• What is meant by a "particle" or a "wave"
• Are photons affected by gravity
• De Broglie's relationship
• Electron diffraction, Davisson and Germer's experiment
• Pilot waves and concept of wavefunction
• Uncertainty principle and some of its applications
• Energy-time uncertainty, lifetimes of excited states

Recitation, tutorial material and reading suggestions:

• Animation simulating different scenarios from a double slit pattern if electrons were particles or waves.
• Animation simulating electron diffraction from a double slit
• The famous double slit experiment gets a makeover. The article is published in the New Journal of Physics in 2013 and can be accessed here. Note that this thought experiment is incorrectly credited to Feynmann, it was Dirac who first mentioned this experiment in 1930's in his "Principles of Quantum Mechanics". Besides, Davisson and Germer won the Nobel Prize for the experimental verification of electron diffraction. That was in 1937!
• read chapter 5 of Serway's book
• Recitation 4.1 and Tutorial 4.1, both dealing with matter waves and providing examples of when to use relativistic and non-relativistic expressions for energy.
• Recitation 4.2 and Tutorial 4.2, cover various aspects of matter waves and application of the uncertainty principle.
• This link has a wonderful simulation of an interferometer - comprising two beamsplitters and two mirrors, similar to the case we discussed in class. It will be helpful in determining when quantum interference does or does not take place and is highly recommended before you attempt Home Work number 3.
• Recitation 4.3 and Tutorial 4.3 are both concerned with the question of finding quantum

The neon tube producing its characteristic orange-red glow.

Video recordings:

The photon has momentum [22]

Double slit experiment with an electron and wave-particle duality (part A) [23]

Double slit experiment with an electron and wave-particle duality (part B) [24]

Introducing the wave function and meaning of wave-particle duality [25]

Meaning of superposition, example of delayed choice interference, collapse [26]

Demystifying the uncertainty principle (part A) [27]

Demystifying the uncertainty principle (part B) [28]

Demystifying the uncertainty principle and demonstration on linewidths (part C) [29]

Demystifying the uncertainty principle (part D) [30]

Homework 3: (on Wavefunctions, collapse and experimenting with beamsplitters)

• Download the homework. Deadline is Thursday 18 April 2013, and here is the solution.

Schrodinger equation applied to simple cases (7 lectures)

Visit the demonstrations page for links to demos shown in class.

• Introducing the Schrodinger equation
• Potential well, bound and free states
• Bouncing quantum atoms, atom optics
• Fluorescence emission from quantum dots
• Tunneling and some of its applications
• Quantum obstacles, barriers
• Nuclear radioactivity, field emission displays, scanning tunnelling microscopes
• Read Chapter 6 and 7 of Serway

Recitation, tutorial material and reading suggestions:

• Recitation 5.1 and Tutorial 5.1 are both concerned with different aspects of the infinite well. Here is the solution of Recitation 5.1; and this time around, I am also providing you with a solution of Tutorial 5.1.
• For introducing and showing the time dependence of the wave functions (stationary as well as superpositions) I am relying on the wonderful java scripts written by W. Christian. You can download these, read up a little bit on them and enjoy in your comfort zone.
• Recitation 5.2 and Tutorial 5.2 both deal with quantum leakage, obstacles, tunneling and reflection from barriers. Recitation 5.2 is also the homework. Here is the homework solution.
• Quiz 6 and its solution.
• Quiz 7 and its solution.

Video recordings:

Confining electrons to Bohrs radii, orbitals and introducing the Schrodinger equation [31]

Potential in a well and fluorescence from quantum dots [32]

Learning some aspects of quantum mechanics using the particle in a well [33]

Time dependence of stationary states, what does a stationary state really mean and its relationship with the uncertainty principle [34]

Time dependence of superposition states, what does a superposition state signify [35]

Quantum obstacles and sloping potential wells [36]

Quantum mechanical tunneling [37]

Quantum technologies (4 lectures)

• Scanning tunneling microscope
• Phonon assisted tunneling and quantum physics of smell
• Flash memory and field-effect transistors (of the MOSFET kind)
• Natural radioactivity
• Single electron transistors
• Lasers, superconductors

Reading suggestions:

• The world's smallest movie can also be seen here.
• Gallery of scanning tunneling micrographs shown in class.
• Here is some information on G proteins used in relaying sensory olfactory signals.
• A collection of slides on single electron transistors, showing actual micrographs and Coulomb oscillations.
• Read pages 436-443 of Serway (sections on light emitting diodes, solar cells, FET's and integrated circuits) as well as section 12.7 on lasers.
• The most important failed physics experiment. Here is another simplified version.

Video recordings:

Scanning tunneling microscopy, alpha decay and world's smallest movie [38]

Quantum sniffing, phonons, and properties of capacitors [39]

The quantum revolution in electronics and single electron transistors [40]

Interfering photons and electrons [41]e