John Watrous
@johnwatrous.bsky.social
Quantum computing educator and researcher. I like math, computer games, and dub techno.
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.
But see if I care. Hereafter you can find my web page at jhwatrous.github.io in case you're looking for 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.
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.
About - John Watrous
johnwatrous.com
August 2, 2025 at 6:16 PM
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.
But see if I care. Hereafter you can find my web page at jhwatrous.github.io in case you're looking for 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.
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.
About - John Watrous
johnwatrous.com
July 23, 2025 at 6:21 PM
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.
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.
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
arxiv.org/abs/2507.11536
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...
arxiv.org
July 16, 2025 at 11:06 AM
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
arxiv.org/abs/2507.11536
Reposted by John Watrous
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...
Comments, feedback and suggestions welcome!
felixleditzky.info/selected_ref...
March 27, 2025 at 5:27 PM
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...
Comments, feedback and suggestions welcome!
felixleditzky.info/selected_ref...
Excellent lecture notes by Richard Kueng on theory of computing and quantum computing.
Last fall I taught two big classes on **computational complexity** (left selfie) and **quantum computing** (right selfie). We had a blast! Lecture notes are here: www.jku.at/fileadmin/gr..., www.jku.at/fileadmin/gr....
It was a lot of work, but now I am happy+proud to share them. Feedback welcome!
It was a lot of work, but now I am happy+proud to share them. Feedback welcome!
March 10, 2025 at 1:21 PM
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/
Thank you Nathaniel for making these videos available to the community. And for QETLAB!
www.youtube.com/@NathanielMath
njohnston.ca/my-websites/
January 9, 2025 at 2:09 PM
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/
Thank you Nathaniel for making these videos available to the community. And for QETLAB!
www.youtube.com/@NathanielMath
njohnston.ca/my-websites/
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.
January 2, 2025 at 3:32 PM
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.
Reposted by John Watrous
Now in one place, my sixty favorite theorems covering the six decades of computational complexity.
blog.computationalco...
blog.computationalco...
Favorite Theorems: The Complete List
Now in one place all of my sixty favorite theorems from the six decades of computational complexity (1965-2024). 2015-2024 Graph Isomorphism...
blog.computationalcomplexity.org
December 4, 2024 at 2:07 PM
Now in one place, my sixty favorite theorems covering the six decades of computational complexity.
blog.computationalco...
blog.computationalco...
Reposted by John Watrous
Overleaf's down, so I'm cancelling research for the day. Everyone go home and play Slay the Spire.
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.
And please don't say Balatro, that game is pretty good but not as good. Just my opinion.
December 3, 2024 at 2:41 PM
Overleaf's down, so I'm cancelling research for the day. Everyone go home and play Slay the Spire.
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.
And please don't say Balatro, that game is pretty good but not as good. Just my opinion.
November 30, 2024 at 2:27 PM
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.
And please don't say Balatro, that game is pretty good but not as good. Just my opinion.
I just set the maximum possible bounty on a Quantum Computing Stack Exchange problem. I could answer myself, but I know many others could too, and this seemed like fun. quantumcomputing.stackexchange.com/questions/40...
What is the complexity of modulo order-finding problem on classical computer?
It doesn't seem to be NP-complete. But has it been proved to be NP-hard?
quantumcomputing.stackexchange.com
November 28, 2024 at 4:56 PM
I just set the maximum possible bounty on a Quantum Computing Stack Exchange problem. I could answer myself, but I know many others could too, and this seemed like fun. quantumcomputing.stackexchange.com/questions/40...