John Watrous

Bluehost seems to be holding my domain name hostage, I gather in an effort to sell me more products and services. Avoid them at all costs.

But see if I care. Hereafter you can find my web page at jhwatrous.github.io in case you're looking for it.

That one episode where they diagonalize is great. So many other shows try to replicate it.

I ditched my old website and created a new one on GitHub Pages:

johnwatrous.com

It's a great option for a static web page, particularly if you like to do your own CSS styling rather than flipping through pre-built templates that are never quite right.

It does not. I resigned my faculty position at the end of 2021 and haven't taught an actual course with registered students since then.

But isn't any course unfinished by definition so long as one is teaching it?

Understanding Quantum Information and Computation This is a course on the theory of quantum computing. It consists of 16 lessons, each with a video and written component, covering the basics of quantum information, quantum algorithms (including query...

After 3 1/2 years of work my course on quantum computing is finally finished — the "Director's Cut" of Understanding Quantum Information and Computation is now available.

arxiv.org/abs/2507.11536

With Chris Knight, Val Kilmer demonstrated that a character can simultaneously be incredibly smart, cool, fun, and genuinely kind. Real Genius was a special movie.

I've been revamping and updating my collection of selected references to topics in quantum information on my homepage.

Comments, feedback and suggestions welcome!

felixleditzky.info/selected_ref...

Excellent lecture notes by Richard Kueng on theory of computing and quantum computing.

Totally awesome. And be sure to check out Nathaniel's 140 other videos on calculus, linear algebra, and Conway's game of life.

Thank you Nathaniel for making these videos available to the community. And for QETLAB!

www.youtube.com/@NathanielMath
njohnston.ca/my-websites/

This reminds me of a QIP talk years ago where someone introduced a technique on some thing or another by some new name. Reinhard Werner was sitting nearby and he muttered, not quite under his breath, "It's called matrix multiplication."

Where to begin? Writing letters, email, reports, trip planning, travel claims, presentations, cleaning, organizing, doing laundry, shovelling snow, trying to get this classical computer in front of me to function properly. Probably not all that much different from any other theorist.

For getting unexciting stuff done, nothing works better for me than setting a timer: 10 minutes, 90 minutes, whatever makes sense. When time's up, I move on to something else and repeat later. It's remarkable what you can accomplish when you just put in the minutes.

Of course, in an ideal world, each paper would receive multiple carefully written reviews that explain the decision in detail. But recognize that this means even more work for others. A preferable solution in my view: people should stop writing so many damn papers!

I think this is it right here. I have felt the frustration of poor reviews — but I've also chaired the QIP PC and served many times, and it's a thankless monster of a job. Most papers will not make the cut for the simple reason that others are seen as stronger.

Making pizza turned out to be incredibly valuable: I still make pizza at home almost every week. Not so much for being a cashier, except maybe for developing empathy for cashiers. Customers can be pretty difficult, as I'm sure anyone who is or was a cashier knows very well.

Here's my work history:

Pizza maker
Grocery store cashier
Blockbuster Video cashier
Math tutor
Teaching/research assistant
Postdoc
Professor
IBM Quantum educator

I guess you took the faster route.

I believe this is because everyone is left-handed in Australia.

Hang in there, they grow up. Before you know it you'll be back to normal gaming hours.

Now in one place, my sixty favorite theorems covering the six decades of computational complexity.

blog.computationalco...

I edit source files in Emacs, run LaTeX from a terminal window, and let Skim auto-reload to see the results, everything local. Feeling like an old-school Gen Xer who mostly works alone. But then again, everything is working fine for me today.

Overleaf's down, so I'm cancelling research for the day. Everyone go home and play Slay the Spire.

I have not played it. It appears to be about 30 years old, which is pretty darn old for a video game. That's like, pre-Black Isle Studios old. Has it stood up this long? Not impossible — I still play Super Metroid on SNES when I visit my childhood home.

I did play Inscription. It was intriguing and fun, but I didn't love it — I guess I found the actual card game itself to be a bit dull and tedious at times.

Downloading...

In that case, yeah — this one is probably not for you.

(Not sure what to feel right now, having put several hundred hours into Civ 6.)

Regarding characters, I love The Defect, but I'd be lying if I didn't admit that The Ironclad is my favorite to play.

But you could die at any time, and when you're dead your dead. So you start a new run. In summary, I don't need motivation to play, I need motivation not to play!

Synergies can be unexpected and incredibly powerful — almost like you've broken the game sometimes. That can be so satisfying! I've actually woken up my son to show him how some killer deck I've built one-shots a boss.

Slay the Spire is all about synergies between your cards and relics, but the choices you're presented with on each run are random. So games are always different and you can't adopt a single strategy, you have to build around what you're offered.

It is my honest opinion that Slay the Spire is one of the greatest games of all time. Greater than infinite replay value — it gets better the more you play.

And please don't say Balatro, that game is pretty good but not as good. Just my opinion.