Classical computer by Ciro Santilli 37 Updated 2025-07-16
In the context of quantum computing of the 2020's, a "classical computer" is a computer that is not "quantum", i.e., the then dominating CMOS computers.
ZX-calculus by Ciro Santilli 37 Updated 2025-07-16
How can we easily prove that that quantum circuit equals the state:
?
The naive way would be to just do the matrix multiplication as explained at Section "Quantum computing is just matrix multiplication".
However, ZX-calculus provides a simpler way.
And even more importantly, sometimes it is the only way, because in a real circuit, we would not be able to do the matrix multiplication
What we do in ZX-calculus is we first transform the original quantum circuit into a ZX graph.
This is always possible, because we can describe how to do the conversion simply for any of the Clifford plus T gates, which is a set of universal quantum gates.
Then, after we do this transformation, we can start applying further transformations that simplify the circuit.
It has already been proven that there is no efficient algorithm for this (TODO source, someone said P-sharp complete best case)
But it has been proven in 2017 that any possible equivalence between quantum circuits can be reached by modifying ZX-calculus circuits.
There are only 7 transformation rules that we need, and all others can be derived from those, universality.
So, we can apply those rules to do the transformation shown in Wikipedia:
Figure 1.
GHZ circuit as ZX-diagram
. Source.
and one of those rules finally tells us that that last graph means our desired state:
because it is a Z spider with and .
Video 1.
Working with PyZX by Aleks Kissinger (2019)
Source. This video appears to give amazing motivation on why you should care about ZX-calculus, it mentions
The CLI tools don't appear to be packaged for Ubuntu 23.10? Annoying... There is a package libapache-jena-java but it doesn't contain any binaries, only Java library files.
To run the CLI tools easily we can download the prebuilt:
sudo apt install openjdk-22-jre
wget https://dlcdn.apache.org/jena/binaries/apache-jena-4.10.0.zip
unzip apache-jena-4.10.0.zip
cd apache-jena-4.10.0
export JENA_HOME="$(pwd)"
export PATH="$PATH:$(pwd)/bin"
and we can confirm it works with:
sparql -version
which outputs:
Apache Jena version 4.10.0
If your Java is too old then then running sparql with the prebuilts fails with:
Error: A JNI error has occurred, please check your installation and try again
Exception in thread "main" java.lang.UnsupportedClassVersionError: arq/sparql has been compiled by a more recent version of the Java Runtime (class file version 55.0), this version of the Java Runtime only recognizes class file versions up to 52.0
        at java.lang.ClassLoader.defineClass1(Native Method)
        at java.lang.ClassLoader.defineClass(ClassLoader.java:756)
        at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
        at java.net.URLClassLoader.defineClass(URLClassLoader.java:473)
        at java.net.URLClassLoader.access$100(URLClassLoader.java:74)
        at java.net.URLClassLoader$1.run(URLClassLoader.java:369)
        at java.net.URLClassLoader$1.run(URLClassLoader.java:363)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:362)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:418)
        at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:352)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:351)
        at sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:621)
Build from source is likely something like:
sudo apt install maven openjdk-22-jdk
git clone https://github.com/apache/jena --branch jena-4.10.0 --depth 1
cd jena
mvn clean install
TODO test it.
If you make the mistake of trying to run the source tree without build:
git clone https://github.com/apache/jena --branch jena-4.10.0 --depth 1
cd jena
export JENA_HOME="$(pwd)"
export PATH="$PATH:$(pwd)/apache-jena/bin"
it fails with:
Error: Could not find or load main class arq.sparql
as per: users.jena.apache.narkive.com/T5TaEszT/sparql-tutorial-querying-datasets-error-unrecognized-option-graph
The next big thing by Ciro Santilli 37 Updated 2025-07-16
If you are going to live, you might as well chase one of them.
You might not achieve them in your lifetime, but you never know. At some point, the pieces just "fall into place", and they happen.
And they will all come from deep tech.
Ciro Santilli would like to contribute to them. but this is a bit less realistic than software projects.
But who knows? Maybe he can code some stuff in those areas.
And one can at least have some fun by learning deeply about those subjects.
Electron microscope by Ciro Santilli 37 Updated 2025-07-16
All of them need a vacuum because you can't shoot elecrons through air, as mentioned at Video "50,000,000x Magnification by AlphaPhoenix (2022)".
Backward design by Ciro Santilli 37 Updated 2025-07-16
This is one of Ciro Santilli's most important principles.
Steve Jobs has a great quote about this. He's totally right on this one!
You've got to start with the customer experience and work backwards to the technology. You can't start with the technology and try to figure out where you're going to sell it.
Video 1.
Steve Jobs Insult Response excerpt from the 1997 WWDC
. Source. TODO understand the context of the question a bit better. It is something to do with an OpenDoc thing and Java.
Decide your goal first, and then do whatever is needed to how to reach it.
Don't start randomly learning tech, because that means you will waste a lot of time learning useless stuff.
There is of course some level chicken-and-egg paradox in this, as highlighted by Dilbert, since choosing an achievable goal in the first place requires some level of technical understanding.
Figure 1.
Dilbert cartoon about designing a nuclear power plant from user requirements (2002)
Source.
This cartoon illustrates well how when doing deep tech and fighting against the laws of physics, you can't just start from user requirements, but you also have to also think "what can we actually get done at all with this new technique".
The best research engineers are able to identify what is just on the cusp of the "possible", but which has the greatest value. This is the endless dance between the tech push, and the market/need pull.
However, it is much more common that people will get way too involved in learning useless stuff and lose sight of the useful end goals.
Rather, take an iterative approach:
There is some truth to the counter argument that "but if you don't spend a lot of time learning the basics, you can never find solutions".
However, these people underestimate your brain. The brain is beautiful, and human intuition is capable of generating interest towards the things that are actually useful to reach your goal. When you feel like learning something related to your goal, by all means, give yourself the time to do so. But this still be much more efficient than just learning random things that other people tell you to learn.
Bibliography:
Ciro Santilli is against affirmative action university entry quotas that reserve spaces e.g. for students from discriminated races or poor families. Instead, he believes that affirmative action should take place on earlier stages of education as described at: free gifted education.
Notably, Brazil has implemented a very heavy university entry quota system after Ciro had left university there: www.bbc.co.uk/news/business-23862676
This is of course easy for a white male from a privileged background to say, and infinite debate has already been had on this matter, but here goes again.
First, in defense to the personal attack, Ciro raises the fact that he has dedicated large chunks (all?) of his life to open source software and knowledge in general, which Ciro believes is the only way to actually make the world fairer to poor countries. His money (time) is where his mouth is.
One good argument in favor of the Brazilian quota system, is that the kids who enter university because of quotas do just as well as those who don't.
Ciro has actually believes that this is possible, and offers the following possible explanation: most of pre-university knowledge is useless, and university selection system is crap, and Ciro wants to destroy it with a system in which anyone can learn university stuff from home.
Both the top end of the quota and non-quota kids are basically equally capable of doing useful stuff therefore.
Only a tiny fraction of what you learn in high school is useful for university or your career.
And possibly more importantly than knowledge, Ciro saw many of his colleagues (basically all of which were from relatively privileged backgrounds) "do badly" in university, because of lack of motivation, because they had chosen a course only to find that they were not interested in it because the existing high school educational system is crap and does not help them find what they love and because it costs you several years of your life to change your choice in most universities (long live École Polytechnique).
Maybe the fact that poor kids know that they are fucked if they fail, and so they have to succeed at any cost, might also help with motivation. Which is a terrible terrible thing, because only those who have to leeway to take risks end up taking them and making the the next big thing.
Ciro believes instead that only once kids have learnt university level stuff in their area of interest for free on the Internet should they go through selection based on that specific and much more concentrated useful knowledge.
And this competition must only be used to distribute resources which you can't learn from fucking computers:
Once this point knowledge is reached however, it starts to become unclear if a single "everyone takes the same test to avoid discrimination" test is feasible anymore, and we start entering the much more relevant (and potentially discriminatory) "I am a teacher trying to advance the state of the art, and I need a person mildly skilled in the art to do some slave labor for me", which is PhDs selection work.
If quota are in place, what will happen is that parents of the rich kids will start investing less in education, and possibly just put their kids in high schools, and do home schooling instead. This would therefore reduce the total investments the country makes in education!
Outside of the obvious technical evolution proposed, Ciro is a huge proponent of free gifted education. Or closely related, creating scholarships that focus on poor students. The entry requirements should be the same, but once you qualify, everyone should have enough money to lead a decent life during their studies.
Then let those kids pass exactly the same university entry exams, and watch them crush the average privileged kids.
This advice is similar to what is mentioned at: what poor countries have to do to get richer. When you don't have money to do everything, you must select a few good bets and focus on them. You can't pay a lot to every public school teacher, so you must select a few select places that need it the most. As those smart bets pay off, you start to have more and more money to expand the system further.
Video 1.
Inside Westside Barbell by Vice News (2018)
Source.
One sentence of this nice documentary about the notorious Westside Barbell gym where the openly pro-performance-enhancing-drug powerlifting legend leader and cult-leader-like personality Louis Simmons teaches just stuck to Ciro Santilli's mind. His top tenant and manager Tom Barry talks about Louis:
The man [Louis] lives in his own world, and he just rejects everything outside of it, it doesn't matter. Like: "what's your name"? He doesn't care. If you lift numbers, he cares about that, that's more important.
Ciro admires this level of focus, directness and meritocracy. Just don't take drugs, children. Louis' creation of a cult-like training atmosphere is another interesting aspect, see also: Section "Group students by interest, not by age".
Ciro wonders if Louis is a white supremacist though, this was asked here but is inconclusive. But being composed almost exclusively of a bunch of white bald ex-prisoners in the US makes it a bit suspicious. Racism is bad BTW.
We've created a system where people just wait, and wait, and wait, never really doing what they really want.
They wait through school to get into university.
They wait through university to get to masters.
They wait through masters to get to PhD.
They wait through PhD to become a PI.
And for the minuscule fraction of those that make it, they become fund proposal writers.
And if you make any wrong choice along the, it's all over, you can't continue anymore, the cost would be too great.
So you just become software engineer or a consultant until you die.
Is this the society that we really want?
From True Genius: The Life and Science of John Bardeen Chapter 2 "Roots":
John ([Bardeen].) and Bill ([his brother]) entered the combined seventh-eighth grade at "Uni High," Wisconsin's University High School, in the same year-John from third grade and William from fifth.
Established in September 1911, the school had been conceived as a laboratory for training high school instructors and for testing progressive ideas in education. In its philosophy and organization, Uni resembled the Dewey School. The students were accelerated as much as possible to keep lessons challenging. One goal was to "introduce pupils to high school methods and subjects before they reached the 9th grade." The fourth quarter, offered during the summer, allowed students who had missed work or had fallen behind to catch up. It also enabled the brightest students to complete senior high school in only three years
...
Even with the disruption of Althea’s death, John completed all his Uni High course work by age thirteen. But as he was "a little leery about graduating so young," he and Bill decided to attend Madison Central High School for two years, taking additional mathematics, science, and literature courses not offered at Uni. By the time John had turned fifteen and Bill seventeen, the two had completed every course of interest at Madison Central. There was no longer any reason to postpone entering college. In the fall of 1923 they both entered the freshman class at the University of Wisconsin.
Meanwhile, at the University of Oxford www.theguardian.com/uk/2005/aug/21/highereducation.accesstouniversity Oxford to turn away child prodigies
We have been pushed to consider it, not because of concerns about whether it is psychologically healthy for children to study here, but because of child protection laws which have come into play this year for the first time.
FUUUUUUUCK. And so, in protecting children, we also rob them of their own future. But the official policy as of 2023 is unchanged at least in theory: uni-of-oxford.custhelp.com/app/answers/detail/a_id/557/~/do-oxford-undergraduate-courses-have-a-minimum-age-requirement%3F Article also mentions Yinan Wang. Can't find his profiles now.
Bibliography:

Pinned article: Introduction to the OurBigBook Project

Welcome to the OurBigBook Project! Our goal is to create the perfect publishing platform for STEM subjects, and get university-level students to write the best free STEM tutorials ever.
Everyone is welcome to create an account and play with the site: ourbigbook.com/go/register. We belive that students themselves can write amazing tutorials, but teachers are welcome too. You can write about anything you want, it doesn't have to be STEM or even educational. Silly test content is very welcome and you won't be penalized in any way. Just keep it legal!
We have two killer features:
  1. topics: topics group articles by different users with the same title, e.g. here is the topic for the "Fundamental Theorem of Calculus" ourbigbook.com/go/topic/fundamental-theorem-of-calculus
    Articles of different users are sorted by upvote within each article page. This feature is a bit like:
    • a Wikipedia where each user can have their own version of each article
    • a Q&A website like Stack Overflow, where multiple people can give their views on a given topic, and the best ones are sorted by upvote. Except you don't need to wait for someone to ask first, and any topic goes, no matter how narrow or broad
    This feature makes it possible for readers to find better explanations of any topic created by other writers. And it allows writers to create an explanation in a place that readers might actually find it.
    Figure 1.
    Screenshot of the "Derivative" topic page
    . View it live at: ourbigbook.com/go/topic/derivative
  2. local editing: you can store all your personal knowledge base content locally in a plaintext markup format that can be edited locally and published either:
    This way you can be sure that even if OurBigBook.com were to go down one day (which we have no plans to do as it is quite cheap to host!), your content will still be perfectly readable as a static site.
    Figure 5. . You can also edit articles on the Web editor without installing anything locally.
    Video 3.
    Edit locally and publish demo
    . Source. This shows editing OurBigBook Markup and publishing it using the Visual Studio Code extension.
  3. https://raw.githubusercontent.com/ourbigbook/ourbigbook-media/master/feature/x/hilbert-space-arrow.png
  4. Infinitely deep tables of contents:
    Figure 6.
    Dynamic article tree with infinitely deep table of contents
    .
    Descendant pages can also show up as toplevel e.g.: ourbigbook.com/cirosantilli/chordate-subclade
All our software is open source and hosted at: github.com/ourbigbook/ourbigbook
Further documentation can be found at: docs.ourbigbook.com
Feel free to reach our to us for any help or suggestions: docs.ourbigbook.com/#contact