Fall 2025 Review in Tweets
Happy first day of school! This semester, I'm teaching:
— Tom Wong (@thomasgwong) August 19, 2025
1. #PHY131 Quantum Physics and Technology for Everyone #QuantumForEveryone, a new 2-credit general education course
2. #PHY201 General Physics for the Life Sciences 1 #GenPhys1
3. #PHY531 #QuantumMechanics
Today in #PHY531 #QuantumMechanics: One at a time, electrons are shot at two slits. The resulting distribution resembles a wave's interference pattern. A wave determines the likelihood of the particle's position. It's particle-wave duality! Picture from https://t.co/GmDrhSJFWH. pic.twitter.com/67f4Frw85p
— Tom Wong (@thomasgwong) August 20, 2025
Today in #PHY531 #QuantumMechanics: The wave function for a wave on a string describes the height of the wave, but a quantum wave function is statistical. Its norm-square gives the probability density of where the particle will be found, and it collapses upon measurement.
— Tom Wong (@thomasgwong) August 22, 2025
Today in #PHY531 #QuantumMechanics: Quantum waves are statistical, so let's review probability. Averages include mode (most probable value), median (middle value), & mean (expected value). For spread, the average deviations from the mean is zero, so average the square deviation.
— Tom Wong (@thomasgwong) August 25, 2025
Today in #PHY531 #QuantumMechanics: Review of probability with continuous variables, which mirrors the equations for discrete variables. pic.twitter.com/zuM7CY780b
— Tom Wong (@thomasgwong) August 27, 2025
Today in #PHY531 #QuantumMechanics: For a plane wave to obey the de Broglie relations, energy and momentum are differential operators. The Hamiltonian is kinetic plus potential energy, yielding Schrödinger's equation. Experiments show the equation holds for other wave functions. pic.twitter.com/4DuxXKjwVb
— Tom Wong (@thomasgwong) August 29, 2025
Today in #PHY531 #QuantumMechanics: The expectation value of a quantity is obtained replacing momentum with an operator, sandwiching, and integrating over space. Heisenberg's uncertainty principle quantifies the tradeoff of the standard deviation of position and momentum. pic.twitter.com/mVTNi0sMxG
— Tom Wong (@thomasgwong) September 3, 2025
Today in #PHY531 #QuantumMechanics: For a time-independent potential, the particular solutions to Schrödinger's equation are separable, obtained from the eigenfunctions/values of the Hamiltonian, have constant expectation values, and have definite energy equal to the eigenvalue. pic.twitter.com/yRMb2T8Qni
— Tom Wong (@thomasgwong) September 8, 2025
Today in #PHY531 #QuantumMechanics: For a particle trapped in a infinitely tall box, the states of definite energy are sine waves with nodes at the ends, and the corresponding energies En are quadratic in n. pic.twitter.com/ddr4DD3Wvd
— Tom Wong (@thomasgwong) September 11, 2025
Today in #PHY531 #QuantumMechanics: A particle in a box whose initial wave function is an upside-down parabola can be written as a linear combination of energy eigenfunctions, which is its Fourier series. Its probability density function evolves as shown. pic.twitter.com/33punZsoue
— Tom Wong (@thomasgwong) September 13, 2025
Page Last Updated: September 15, 2025