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Flip Tanedo @fliptanedo.bsky.social · 08/05/2026

Finally, when students ask why I don't use Canvas, I point them to the article "EdTech" by @anniemcc.bsky.social and Louise McCune in University Keywords (ed. Andy Hines). Today's Canvas outage and resulting disruptions may offer some time to read that article. Attached are some highlights.

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Flip Tanedo @fliptanedo.bsky.social · 08/05/2026

13. Go to Gmail and paste into the "To:" field. Proceed to send your emails a rant about the failures of learning management systems.

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Flip Tanedo @fliptanedo.bsky.social · 08/05/2026

12. To quickly fill in the column, grab the little blue dot on the bottom right and just pull it down, highlighting the column. This will apply the function to successive rows. (Useful when you have 100+ students.) From there you can copy the entire column to get a list of emails.

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Flip Tanedo @fliptanedo.bsky.social · 08/05/2026

11. Then it should output the email. I have doctored the first row here for FERPA reasons. (You know... FERPA? The reason why Canvas is down because of a data breach...)

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Flip Tanedo @fliptanedo.bsky.social · 08/05/2026

9. Navigate back to your Google Sheet and create a column for emails. In the first data cell, insert a call for the function we just wrote. Here A2 is the cell with the first student's name, which has a hyperlink to send that student an email.

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Flip Tanedo @fliptanedo.bsky.social · 08/05/2026

8. Give the Apps Script project a name and save it.

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Flip Tanedo @fliptanedo.bsky.social · 08/05/2026

7. Write up a script that does what we want. Here's one that Gemini helped put together. You can copy the text from here: gist.github.com/fliptanedo/d...

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Flip Tanedo @fliptanedo.bsky.social · 08/05/2026

Your CSV file is now in Google Sheets. We need to create a function that extracts the email addresses from the hyperlinks in the student names. To do this, we use Google Apps Script. 6. In Google Sheets, go to Extensions > Apps Ssript

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Flip Tanedo @fliptanedo.bsky.social · 08/05/2026

5. Confirm that you're importing the file into Google Sheets.

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Flip Tanedo @fliptanedo.bsky.social · 08/05/2026

4. Click on upload a file, and upload the csv file from iGrade.

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Flip Tanedo @fliptanedo.bsky.social · 08/05/2026

2. Go to Google Sheets and create a new spreadsheet.

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Flip Tanedo @fliptanedo.bsky.social · 08/05/2026

If you want an email list, we can use Google Sheets to do that. 1. From iGrade, go to your class and download your roster. This gives a civ file that looks almost useless, except that each students' name is hyperlinked to their email address. The problem is now to extract those email addresses.

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Flip Tanedo @fliptanedo.bsky.social · 08/05/2026

Simplest solution: go to iGrade and click on the "email class" button.

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Flip Tanedo @fliptanedo.bsky.social · 05/04/2025

The remaining term is proportional to the curvature tensor with its three lower indices antisymmetrized (blue). The entire quantity is zero (first step) and for any scalar (dot) or vector (circle), thus the blue highlighted piece must vanish. This proves the assertion.

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Flip Tanedo @fliptanedo.bsky.social · 05/04/2025

All but the last term vanish: the first one from torsion freedom, and the second from a combined symmetrization and anti-symmetrization of the same pair of indices.

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Flip Tanedo @fliptanedo.bsky.social · 05/04/2025

Apply the chain rule for the inner (highlighted in blue) covariant derivative. This means the dashed blue circle is applied to each node inside it.

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Flip Tanedo @fliptanedo.bsky.social · 05/04/2025

The first step, following a hint from Penrose's book, is to evaluate the following quantity for some arbitrary vector field (ξ) and scalar field (φ). By the torsion free condition (highlighted in yellow) this quantity is zero. Next we expand the left-hand side.

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Flip Tanedo @fliptanedo.bsky.social · 05/04/2025

The (Riemann) curvature is analogously defined from an antisymmetric covariant derivative.

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Flip Tanedo @fliptanedo.bsky.social · 05/04/2025

The torsion free condition is that the antisymmetric second derivative of a scalar vanishes.

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Flip Tanedo @fliptanedo.bsky.social · 05/04/2025

Wigglies (bars) indicate (anti-)symmetrization of indices.

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Flip Tanedo @fliptanedo.bsky.social · 05/04/2025

Covariant derivatives are dashed circles.

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Flip Tanedo @fliptanedo.bsky.social · 05/04/2025

Some notational background: Tensors are nodes and indices are lines. Lines that connect nodes are contracted.

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Flip Tanedo @fliptanedo.bsky.social · 05/04/2025

Here's an application of birdtrack notation to prove a curvature tensor identity. It is identical to index notation, but I find the diagrammatic proof easier to follow once I picked up the rules. This is a solution to exercise [14.10] in Penrose's Road to Reality.

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Flip Tanedo @fliptanedo.bsky.social · 17/03/2025

This month and next month our Phy-Sci Book club is reading a couple of books ahead of Earth Day. Next week we're discussing Rachel Carson's classic, Silent Spring. The book continues to hold its own as remarkable feat of accessible science writing 63 years after its original publication.

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Flip Tanedo @fliptanedo.bsky.social · 14/02/2025

The lectures begin from causality and the analytic properties of the classical Green's function for the harmonic oscillator, and builds up towards the present S-matrix bootstrap program.

"The goal of these lecture notes is to introduce the subject of the analytic S-matrix from the physics perspective, the way I would’ve wanted to learn it back when I was a student"

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Flip Tanedo @fliptanedo.bsky.social · 09/02/2025

The attendees included my own high school science teacher, Altair Maine (North Hollywood High School, LAUSD); and a @ucriverside.bsky.social physics alumnus Adam Christensen (King High School, RUSD), who was in some of the first courses I taught at UCR.

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Flip Tanedo @fliptanedo.bsky.social · 09/02/2025

The recorded talks are available here online.kitp.ucsb.edu/online/parti... We had a fantastic lineup of speakers.

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Flip Tanedo @fliptanedo.bsky.social · 09/02/2025

Yesterday we had a fantastic Teachers' Conference at @kitp-ucsb.bsky.social, "This is Particle Theory." The event brings together high school physics teachers to connect to the big ideas in research at the KITP. This year it was associated with our "What is Particle Theory" workshop.

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Flip Tanedo @fliptanedo.bsky.social · 03/02/2025

The details. n.b. I am not affiliated with IAIFI or the school, just passing along the opportunity. Application: iaifi.org/phd-summer-s...

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Flip Tanedo @fliptanedo.bsky.social · 03/02/2025

Applications are open for the IAIFI Summer School on AI+Physics. iaifi.org/phd-summer-s... #physics #machine-learning

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Flip Tanedo @fliptanedo.bsky.social · 01/02/2025

... I was reminded of this old New Yorker cartoon, which has been lightly adapted. Original from: Paul Noth (www.paulnoth.com) 2011 ("Nobody ever asks *how* is Waldo.")

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Flip Tanedo @fliptanedo.bsky.social · 01/02/2025

... it has also created a theme for all program-related activities. Social events include "What is barbecue?" "What is [Joe's] bike ride?" "What is margarita?" and "What is pub quiz?"

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Flip Tanedo @fliptanedo.bsky.social · 11/01/2024

Applications for TASI 2024 are due March 1st. www.colorado.edu/physics/even...

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Flip Tanedo @fliptanedo.bsky.social · 10/01/2024

The @nytimes.com highlights CERN as one of the "52 places to go in 2024." nytimes.com/interactive/...

Geneva, Switzerland: Satisfy your curiosity about quantum physics, and your cravings for chocolate.

https://nytimes.com/interactive/2024/travel/places-to-travel-destinations-2024.html

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Flip Tanedo @fliptanedo.bsky.social · 20/12/2023

This is part of our [relatively] new UCR course, Physics 17: Linear Algebra for Physicists course, next offered in Spring 2024. sites.google.com/ucr.edu/phys... [Forgive the typos in the table below. I'll leave it to my students to catch them later.]

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Flip Tanedo @fliptanedo.bsky.social · 20/12/2023

We can write the general definition of the adjoint in my birdtracks-variant notation like this. The dashed lines are barred (conjugated) indices.

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Flip Tanedo @fliptanedo.bsky.social · 20/12/2023

The condition for isometries in complex space takes the same form as we saw for real space. This condition is the familiar one for unitary matrices.

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Flip Tanedo @fliptanedo.bsky.social · 20/12/2023

If the metric is the identity, then the adjoint is the conjugate-transpose in matrix notation. This is physicists call this the Hermitian conjugate and are introduced to it in quantum mechanics.

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Flip Tanedo @fliptanedo.bsky.social · 20/12/2023

We can go through the same argument for complex vector spaces. Here the vectors are complex and we use a bar as shorthand for complex conjugation.

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Flip Tanedo @fliptanedo.bsky.social · 20/12/2023

In a variant of so-called birdtracks notation, one may write the isometry condition as follows. Lines represent indices. The crossed line on the left indicates the "transpose-y" part of the adjoint.

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Flip Tanedo @fliptanedo.bsky.social · 20/12/2023

From the [linear] algebraic point of view, it is more natural to write this condition with the metric and inverse metric explicitly. One may also use the adjoint as shorthand for the metric dependence.

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Flip Tanedo @fliptanedo.bsky.social · 20/12/2023

The Lorentz transform is often written in "matrix notation" in a way that can be puzzling, especially to those first trying to make sense of tensor notation.

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Flip Tanedo @fliptanedo.bsky.social · 20/12/2023

More generally, the adjoint is the more significant quantity and unlike the transpose, it depends on the metric. This shows up in special relativity. Lorentz transformations are those which preserve the metric.

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Flip Tanedo @fliptanedo.bsky.social · 20/12/2023

*If* the metric is simply the identity, then the adjoint is what we normally call the transpose in matrix language. The index heights changed, which is usually not allowed. We have implicitly used the metric (identity) to write 1st index up/2nd index down.

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Flip Tanedo @fliptanedo.bsky.social · 20/12/2023

The natural manifestation of the transpose in this language is something called the adjoint. Given a linear transformation A, the adjoint is the linear transformation that satisfies:

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Flip Tanedo @fliptanedo.bsky.social · 20/12/2023

In a metric space you can raise and lower indices. The metric defines an inner product, a bilinear function on vectors that we may write in angle bracket notation. For real spaces, the inner product (and thus the metric) is symmetric.

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Flip Tanedo @fliptanedo.bsky.social · 20/12/2023

We like writing tensors with indices because the heights of the indices are shorthand for how the tensor transforms under an isomorphism (symmetry of the space). We do this even if we know our math colleagues giggle when they see us doing this.

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Flip Tanedo @fliptanedo.bsky.social · 20/12/2023

Physicists like tensors. Lower and upper indices indicate linear functions of the (dual) vector space. Repeated upper and lower indices indicate a contraction, or a sum over all possible index values. “Matrices” are (1,1) tensors that map vectors to vectors.

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Flip Tanedo @fliptanedo.bsky.social · 20/12/2023

If we define a matrix to be an array of numbers, the transpose flips the array along the diagonal.

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