Philosophically, superconducting qubits are good because superconductivity is macroscopic.
It is fun to see that the representation of information in the QC basically uses an LC circuit, which is a very classical resonator circuit.
As mentioned at en.wikipedia.org/wiki/Superconducting_quantum_computing#Qubit_archetypes there are actually a few different types of superconducting qubits:
- flux
- charge
- phase
Input:
Quantum Computing with Superconducting Qubits by Alexandre Blais (2012)
Source. - youtu.be/uPw9nkJAwDY?t=293 superconducting qubits are good because superconductivity is macroscopic. Explains how in non superconducting metal, each electron moves separatelly, and can hit atoms and leak vibration/photos, which lead to observation and quantum error
- youtu.be/uPw9nkJAwDY?t=429 made of aluminium
- youtu.be/uPw9nkJAwDY?t=432 shows the circuit diagram, and notes that the thing is basically a LC circuitusing the newly created just now Ciro's ASCII art circuit diagram notation. Note that the block on the right is a SQUID device.
+-----+ | | | +-+-+ | | | C X X | | | | +-+-+ | | +-----+ - youtu.be/uPw9nkJAwDY?t=471 mentions that the frequency between states 0 and 1 is chosen to be 6 GHz:This explains why we need to go to much lower temperatures than simply the superconducting temperature of aluminum!
- higher frequencies would be harder/more expensive to generate
- lower frequencies would mean less energy according to the Planck relation. And less energy means that thermal energy would matter more, and introduce more noise.6 GHz is aboutFrom the definition of the Boltzmann constant, the temperature which has that average energe of particles is of the order of:
- youtu.be/xjlGL4Mvq7A?t=138 superconducting quantum computer need non-linear components (too brief if you don't know what he means in advance)
- youtu.be/xjlGL4Mvq7A?t=169 quantum computing is hard because we want long coherence but fast control
Many subjects have changed very little in the last hundred years, and so it is mind-blowing that people have to pay for books that teach them!
Since Ciro Santilli was young, he has been bewildered by the natural sciences and mathematics due to his bad memory.
The beauty of those subjects has always felt like intense sunlight in a fresh morning to Ciro. Sometimes it gets covered by clouds and obscured by less important things, but it always comes back again and again, weaker or stronger with its warmth, guiding Ciro's life path.
As a result, he has always suffered a lot at school: his grades were good, but he wasn't really learning those beautiful things that he wanted to learn!
First, before university, school organization had only one goal: put you into the best universities, to make a poster out of you and get publicity, so that more parents will be willing to pay them money to put their kids into good university.
Ciro once asked a chemistry teacher some "deeper question" after course was over, related to the superficial vision of the topic they were learning to get grades in university entry exams. The teacher replied something like:Ciro feels that this was one of the greatest compliments he has ever received in his life. This teacher, understood him. Funny how some things stick, while all the rest fades.
You remind me of a friend of mine. He always wanted to understand the deeper reason for things. He now works at NASA.
Another interesting anecdote is how Ciro Santilli's mother recalls that she always found out about exams in the same way: when the phone started ringing as Ciro's friends started asking for help with the subjects just before the exam. Sometimes it was already too hopelessly late, but Ciro almost always tried. Nothing shows how much better you are than someone than teaching them.
Then, after entering university, although things got way better because were are able to learn things that are borderline useful.
Ciro still felt a strong emotion of nostalgia when after university his mother asked if she could throw away his high school books, and Ciro started tearing them all down for recycling. Such is life.
University teachers were still to a large extent researchers who didn't want to, know how to and above all have enough time and institutional freedom to teach things properly and make you see their beauty, some good relate articles:
The very fact that you had very little choice of what to learn so that a large group can get a "Diploma", makes it impossible for people to deeply learn what the really want.
This is especially true because Ciro was in Brazil, a third world country, where the opportunities are comparatively extremely limited to the first world.
Also extremely frustrating is how you might have to wait for years to get to the subject you really want. For example, on a physics course, quantum mechanics is normally only taught on the third year! While there is value to knowing the pre-requisites, holding people back for years is just too sad, and Ciro much prefers backward design. And just like the university entry exams, this creates an entry barrier situation where you might in the end find that "hey, that's not what I wanted to learn after all", see also: students must have a flexible choice of what to learn.
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. Is this the society that we really want?
And all of this is considering that he was very lucky to not be in a poor family, and was already in some of the best educational institutions locally available already, and had comparatively awesome teachers, without which he wouldn't be where he is today if he hadn't had such advantages in the first place.
But no matter how awesome one teacher is, no single person can overcome a system so large and broken. Without technological innovation that is.
The key problem all along the way is the Society's/Government's belief that everyone has to learn the same things, and that grades in exams mean anything.
Even if you wanted to really learn natural sciences and had the time available, it is just too hard to find good resources to properly learn it. Even attending university courses are hit and miss between amazing and mediocre teachers.
If you go into a large book shop, the science section is tiny, and useless popular science books dominate it without precise experiment descriptions. And then, the only few "serious" books are a huge list of formulas without any experimental motivation.
And if you are lucky to have access to an university library that has open doors, most books are likely to be old and boring as well. Googling for PDFs from university courses is the best bet.
Around 2012 however, he finally saw the light, and started his path to Ciro Santilli's Open Source Enlightenment. University was not needed anymore. He could learn whatever he wanted. A vision was born.
To make things worse, for a long time he was tired of seeing poor people begging on the streets every day and not doing anything about it. He thought:which like everything else is likely derived subconsciously from something else, here Schindler's list possibly adapted quote from the Talmud:
He who teaches one thousand, saves one million.
So, by the time he left University, instead of pursuing a PhD in theoretical Mathematics or Physics just for the beauty of it as he had once considered, he had new plans.
We needed a new educational system. One that would allow people to fulfill their potential and desires, and truly improve society as a result, both in rich and poor countries.
And he found out that programming and applied mathematics could also be fun, so he might as well have some fun while doing this! ;-)
So he started Booktree in 2014, a GitLab fork, worked on it for an year, noticed the approach was dumb, and a few years later started building this new version. The repo github.com/booktree/booktree is a small snapshot of Ciro's 2014 brain on the area, there were quite a few similar projects at the time, and most have died.
Ciro is basically a librarian at heart, and wants to be the next:
- Jimmy Wales
- Brewster Kahle
- Tim Berners Lee
- Tim O'Reilly, who once brilliantly described O'Reilly Media as "a lifestyle business that got out of control" [ref]
- Aaron Swartz. Minus suicide hopefully.
The point of these is that they are good for transfection apparently.
OpenSuperQ intro by Quantum Flagship (2021)
Source. Similar to quantum supremacy, but add the goal that the computation must be useful, i.e. make money or solve some open mathematical problem, Ciro Santilli's wife was quite excited about the possibility of finding some counter examples in number theory with quantum computers.
phys.libretexts.org/Courses/University_of_California_Davis/UCD%3A_Physics_9HE_-_Modern_Physics/06%3A_Emission_and_Absorption_of_Photons/6.2%3A_Selection_Rules_and_Transition_Times has some very good mentions:
So it appears that if a hydrogen atom emits a photon, it not only has to transition between two states whose energy difference matches the energy of the photon, but it is restricted in other ways as well, if its mode of radiation is to be dipole. For example, a hydrogen atom in its 3p state must drop to either the n=1 or n=2 energy level, to make the energy available to the photon. The n=2 energy level is 4-fold degenerate, and including the single n=1 state, the atom has five different states to which it can transition. But three of the states in the n=2 energy level have l=1 (the 2p states), so transitioning to these states does not involve a change in the angular momentum quantum number, and the dipole mode is not available.So what's the big deal? Why doesn't the hydrogen atom just use a quadrupole or higher-order mode for this transition? It can, but the characteristic time for the dipole mode is so much shorter than that for the higher-order modes, that by the time the atom gets around to transitioning through a higher-order mode, it has usually already done so via dipole. All of this is statistical, of course, meaning that in a large collection of hydrogen atoms, many different modes of transitions will occur, but the vast majority of these will be dipole.It turns out that examining details of these restrictions introduces a couple more. These come about from the conservation of angular momentum. It turns out that photons have an intrinsic angular momentum (spin) magnitude of , which means whenever a photon (emitted or absorbed) causes a transition in a hydrogen atom, the value of l must change (up or down) by exactly 1. This in turn restricts the changes that can occur to the magnetic quantum number: can change by no more than 1 (it can stay the same). We have dubbed these transition restrictions selection rules, which we summarize as:
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!
Intro to OurBigBook
. Source. We have two killer features:
- 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-calculusArticles 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/derivativeVideo 2. OurBigBook Web topics demo. Source. - 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.
- to OurBigBook.com to get awesome multi-user features like topics and likes
- as HTML files to a static website, which you can host yourself for free on many external providers like GitHub Pages, and remain in full control
Figure 3. Visual Studio Code extension installation.
Figure 4. Visual Studio Code extension tree navigation.
Figure 5. Web editor. 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.Video 4. OurBigBook Visual Studio Code extension editing and navigation demo. Source. 
- Infinitely deep tables of contents:
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