Meetings 2020

[ Click here for Past Meetings ]

How to attend the online meetings

If you haven’t attended these meetings before, you may need to email Mike in order to get the information needed to join: msg2mw (at)

Sunday December 20th: NO MEETING

Sunday December 27th: NO MEETING

Hopefully by January 10th we’ll be starting on a new series. Possibility 1: Start off with the classical harmonic oscillator, move on the the quantum oscillator, and then use coupled oscillators as an entry point into quantum field theory. Possibility 2: Time – its (arguable) physical basis and relationship to statistical mechanics and entropy.

Both of these potential topics have words in them that sound daunting for some of the group. But the intention is, in both cases, to start off with very basic concepts and math which will be understandable to everybody.

When we start, and which topic we start with, will basically depend on what I can get ready and when. Of course any help would be appreciated.

Past Meetings

Sunday December 13th: Interpretations of Quantum Theory II

Sunday December 6th: Interpretations of Quantum Theory I

Sunday November 29th: Group Social

It’s been a while since we’ve just gotten together to chat. Among other things we can discuss plans for the rest of the year and beyond. Regular Sunday Zoom Link.

Sunday November 22nd: Wayne – Advanced Eigenvalues and Eigenvectors, Part IV

Sunday November 15th: Wayne – Advanced Eigenvalues and Eigenvectors, Part III

Sunday November 8th: NO MEETING

Sunday November 1st: Matthew – Heisenberg Uncertainty Principle, Part III

Sunday Oct 25th: Matthew – Heisenberg Uncertainty Principle, Part II

Sunday Oct 18th: Matthew – Heisenberg Uncertainty Principle

Sunday Oct 11th: NO MEETING

Sunday October 4th: Advanced Eigenvalues and Eigenvectors, Part II

Sunday Sept 27th: Wayne – Advanced Eigenvalues and Eigenvectors

Sunday Sept 20th: John – The Stern-Gerlach Experiment

Sunday Sept 13th: Pure and Mixed States, the Density Matrix III

Sunday Sept 6th: Pure and Mixed States, the Density Matrix II

Sunday Aug 30th: Pure and Mixed States, the Density Matrix I

Sunday August 23rd: QM#6 – The Free Particle (Rescheduled)

Sunday Aug 16th: Superdense Coding (Rescheduled)

Sunday August 9th: Quantum Teleportation II

Friday August 7th: John – Teleportation supplemental 2

Monday August 3rd: Teleportation supplemental

Sunday August 2nd: Quantum Teleportation I

Sunday July 26th: QM#5 – 1D Position States

Sunday July 19th: Linearity and the No Cloning Theorem

Tuesday July 14th: QM#4 – Schrödinger’s Equation

Sunday July 12th: Multi-Bit Operations

Sunday July 5th: The Bell States
There is homework to do before the meeting!

Tuesday June 30: QM#3 – Background on Differential Equations

Sunday, 28 June: Continue on the Tensor Product (Section 8)
(I’ll keep using the same entry in the meeting forum for now.)

Tuesday June 23rd: QM#2 Transition from discrete to continuous space

Sunday, 21 June: Starting on Quantum Information

Tuesday June 16th: QM#1 Orientation

Sunday June 14th: Electron Spin II

We’ll be working exercises together.

Tuesday June 9th: SR/GR III

Sunday June 7th: Electron Spin

Today we’ll start on quantum theory, with section 6 on Electron Spin.

Sunday May 31st: Group Social

We’re finished reviewing math concepts and next week we’ll start on quantum theory. So this seems like a good time to get together and just chat: Sunday-31-may-group-social.
Note the link which you may not have used before.

Tuesday May 26th: SR/GR II

Wayne is doing a three-part series on special and general relativity.

Sunday May 24th: Complex Vector Spaces

Eduard will go over section 4 on Complex Vector Spaces.

Tuesday May 19th: SR/GR I

Wayne is doing a three-part series on special and general relativity.

Sunday May 17th: Complex Numbers

John went over Section 3 on Complex Numbers.

Tuesday May 12th: Website Status / Q&A

There’s more information in the meeting forum. If you don’t have access to that, email Mike.

Sunday May 10th: Matrices

John covered section 2 on Matrices. Pages 14 through 17. This is only four pages, but there is a lot of material here, covering: matrix multiplication, the transpose operation, the identity matrix, inverses, eigenvalues, eigenvectors, and more.


Tuesday May 5th: The Geodesic Equation

This is an advanced topic, which will probably be of interest only to people who have some knowledge of both General Relativity and programming in Python.

The original intent of this meeting was to go over some work I did last year, attempting to use the geodesic equation (numerically) to plot a uniform acceleration path. This was done in Python. Also, the metric tensor from which this particular equation came was taken (somewhat naively) directly from one of Leonard Susskind’s lectures.

Here’s the write-up of this from a meeting of the Denver group last year

Since the meeting was originally scheduled, some things have happened:

(1) Wayne, in Vancouver reviewed the Susskind lecture and thinks that perhaps the metric tensor he gave was simplified to the point that it doesn’t actually represent acceleration relativistically. (Wayne, let me know if I’m misquoting you!)

(2) Tim in Portland found this package:
which appears to be very pertinent to what we’re trying to do here. Nobody has had time to look at it in depth, but Tim might have something to report.

(3) I’ve reviewed my code from last year and I’ve realized that it will not be easy to get it into a “sharable” form, for the purposes of this meeting. It turns out that it’s too dependent a library I’d been putting together to draw space-time (Minkowski) diagrams and I just don’t have the time to pull out the relevant code and make it stand-alone. The spacetime diagram library in itself might be interesting, but that’s a topic that would take some time.

So … what I’m suggesting at this point, is that we have a short get together for anyone who is interested in numerical work with GR, and just discuss our interests and options. I’ll also briefly describe that I was trying to do if anyone is interested.

For those who are interested SR/GR but not in numerics, Wayne has a couple of lectures scheduled later in the month. More information on those will be appearing soon!

Sunday May 3rd: More on Vectors

3:00pm US/CA West Coast Time
References: Notes.pdf, Study Plan
Attending: Buck, David, Eduard, Eugen, Joel, John, Mary Ann, Polly, Sharon, Terrill, Tina, Wayne

John covered the remainder of the section on Vectors, pages 11, 12, and 13. Even though there are only three pages, this material (especially change of basis) requires a lot of explanation.

I put the video in the Meetings Forum.

Sunday April 26th: Vectors

References: Notes.pdf, Other references
Attending: David, Eugen, Joel, John, Mary Ann, Mike, Sharon, Terrill, Tina, Wayne, B., Wayne D.,

We covered the first 10 pages of the notes. We’ll we’ll finish section 1 on vectors next week.

Saturday April 25th: Python Notebook Workshop

This is for people who would like some help setting up and running the group’s Python (or Jupyter) notebooks.

Attending: David, Eugen, Joel, John, Mike, Wayne B., Wayne D.

I attempted to record the meeting, but at some point Zoom kicked me off and I had to rejoin. It appears that the recording was lost at that point.

Also, here is a tutorial on Jupyter notebooks from 2016:
Some parts may be dated, but it could be useful as a compliment to this meeting, for those that are interested.

19 April: First official Physics Cafe meeting


People attending (and please let me know if I have your location wrong!)
Vancouver, BC: Alf, Wayne D.
Rochester, NY: Bert
Portland, OR: David, Eugen, Sharon
Boulder, CO: Eduard, John
Denver, CO: Mike, Tina
Willimantic, CT: Wayne B.

The purpose of this meeting was to discuss the possibility of an online study group to start from a very basic level, go through some of the principles of discrete quantum theory (quantum information) and then go on to tackle the continuous theory (quantum mechanics).

We agreed to start off with this study plan at least as a tentative guide.

2019 Meetings