A free introduction to quantum computing and quantum mechanics
quantum.country
quantum.country
I realise for this audience most people wouldn't get much from it, but I find these rules useful for explaining quantum theory without annoying and fluffy analogies to high school students. You can find the rules in my book _Q is for Quantum_ - Part I which covers quantum computing is a free download on the book website (and the rest will be if I ever get around to producing a corrected pdf, bleh, but if you read part I and don't want to pay for the rest let me know and I'll get it to you...)
A much more interesting example of something similar happens in the Deutch-Hayden version of Heisenberg picture style quantum theory. There from looking at the "state of the world" you can determine which total unitary evolution occurred to get you there. In the Schroedinger picture, if I give you the inital and final states there are many possible unitaries that get you between them. Its possible to go further and come up with versions where not only the total unitary connecting initial and final state is discernable, but also the sequence of Hamiltonian's that implemented it are too.
These things are mainly of interest to people in foundations of course (since they like to play the game of blurring the line between our math and what is "really out there"). I tried to be very careful in the book to maintain the distinction.
Are you aware of anyone who made an interactive version (eg in the browser) of the boxes and balls model? Would be really fun to mess around with it interactively.
A few weeks ago a high school physics teacher who used the book for some extension classes sent me some python code he says will do all of the calculations. I have asked the family friend who maintains the book webpage to put it on there, and I am sure she will when she gets a chance. However if you email me - terry @ qisforquantum.org - it would be great to have someone look at it - I don't know python at all and can't even run it to check it. (I also have some atrocious octave/matlab code of my own which anyone is also welcome to.)
I really believe that we are just now starting to scratch the surface of the learning opportunities that computers present to us and Quantum Country was an interesting step forward in that direction. It is worth looking at some of his previous work with Khan Academy as well, cool stuff.
What were the powerful ideas?
I say that not as a physicist/mathematician looking down at the oiks trying to underastand this stuff, but as one of the oiks.
It's also by design that some of the questions are, as you say, laughably simple. It's to catch people who aren't properly engaging with the text as early as possible.
Nielsen and Matuschak are sensible to these sorts of critiques. Quantum country is part experiment after all and they've been learning, adjusting, and experimenting with what works best. If you want a bit of context of where they've come from and where they want to go, I recommend this: https://numinous.productions/ttft/
>I must confess, I don’t understand what people mean by this.
I think they're just trying to tie it to Schrödinger's cat somehow since that's the only other topic that seems to be covered in pop science.
It does make sense that if we're going to have learning interfaces they have spaced repetition built in rather than requiring users to do that themselves.
Looking forward to reading through.
However
> Presented in a new mnemonic medium which makes it almost effortless to remember what you read
This is just nonsense and quite distracting, even irritating. Quantum computing and quantum mechanics is hard and involves sophisticated concepts. The spaced repetition questions are utterly superficial and represent unhelpful dumbing down.
Apologies for the rant and slightly silly comparison between quantum physics and a programming language but the same goes for the Rust book. Rust is a hard language with sophisticated ideas. Despite the best intentions of the nice people at Mozilla, no amount of dumbing down changes that. And patronizing readers does not make the resource more approachable to women and under-represented minorities, unless you believe that those groups need to be patronized.
> The set of curly brackets, {}, is a placeholder: think of {} as little crab pincers that hold a value in place.
That came out of the blue. Am I missing something? Did mozilla make such an attempt to patronize minorities?
Some fun history here: Ruby uses #{} for string interpolation. I used to teach Ruby to folks as a job, and I believe that my boss, Jeff Casimir, said that they looked like lobster pincers in one of our classes. (If Jeff reads this and that's incorrect, my apologies!)
Years later, when I was writing this part of the book, I remembered this analogy, and we had the whole crab thing going on with Rust, and I thought it was a fun thing. So I put it in the book.
Some people find whimsy inherently patronizing or something. I dunno. It's an offhanded fun comment, not some sort of desire to "dumb things down" for anyone. We don't write anything with the intention of dumbing things down.
It's also true that I worry that the whimsical sentences that seem designed for children are somehow connected with what is often called the "Diversity and Inclusion" movement. In my company, the diversity and inclusion initiatives were characterized by childish activities, such as writing "motivational phrases" on post-its in colored pens and posting them on the walls of the office. The women I've spoken to about this really resented the fact that engaging with pro-women-in-tech initiatives meant having to behave childishly, and they resented even more strongly the implication that childishness was appealing to women and under-represented minorities.
You may have some wires understandably crossed. Companies frequently end up hiring in people for all sorts of initiatives that end up doing some really childish stuff. Diversity and inclusion do not particularly stick out on this front. This is where we end up with the mockery around "trust falls" and that sort of thing, which are childish "team-building" activities, and have you ever seen a corporate presentation on how to do better sales? Yeowzers. It's not specifically a diversity/inclusion thing, it's all the corporations.
On the other side, there is a solid reason to use whimsical, or more accurately, highly visual and emotional analogies for that sort of thing: They're the things our brains remember. You'll encounter that sort of thing in a lot of foreign language courses, memorizing alphabets or symbols with mnemonics meant to engage emotional and visual memories around the item as a bootstrap towards remembering what it is.
That said, it is true these whimsical analogies travel poorly, because your cognitive association network will be different than everybody else's. I've got some mnemonics in my language I'm studying around my kid's pet bird and my wife's interactions with her parents; obviously they wouldn't be very meaningful to you if I tried to give them to you to use as your own association. You ought to make them up yourself for maximum effect. But, my main point here is that they aren't intrinsically silly, they are a legitimate way to remember otherwise difficult-to-remember things. After a decade of programming the meaning of curly braces may be obvious, but it isn't at first.
1. As I say, other people I've spoken to (specifically, some women) share my dismay at the childishness of Diversity and Inclusion initiatives. So that suggests that they also had higher expectations. If you are right, then all of us had poorly calibrated expectations. That starts to seem less plausible; more plausible is that the Diversity and Inclusion sessions were unexpectedly childish even taking into account the background low expectation for any "sessions" / "initiatives".
2. I can think of no reason why Mozilla's documentation for a programming language would share the characteristics of a lame corporate "session" on something non-technical: I think that the people at Mozilla are intelligent and technical-minded, and to some extent work at Mozilla to get away from those depressing and embarrassing aspects of the corporate world. However, it is, as I understand it, an aim of Mozilla to make their technical documentation more approachable to sectors of society that have traditionally been poorly served by the tech community. Therefore one can think of reasons why Mozilla's documentation might share characteristics with the "Diversity and Inclusion movement".
I know I'm sniping at worthy causes, and being slightly insulting about people who have worked hard to document a fantastic programming language, and even I don't think it really comes across pleasantly. The reason I am doing it is because I, along with many others I think, am concerned about the way the political liberal/left (with which I identify) is damaging itself by uncritical adoption of modern dogma of mostly young "progressives"./ And there, in admitting that, I guess I've violated another site guideline.
A Mozilla employee can write something without the contents of the thing being dictated by Mozilla in some fashion.
What you say may be true of Mozilla, but it's not true in general, is it? I mean, suppose two authors work at the same "institution". I think it's bound up in our notion of institution that the observer of this situation might expect, or at least not be surprised if, their creative output is subject to shared influences. So, OK, the theory I was floating was dubious because of its lack of real justification! But I don't think its reliance on a notion of institutional culture (shared influences) was problematic.
Is it the notion of embedding SRS questions into the medium per se. that you find superficial and unhelpful, or just the specific questions that Andy and Michael chose? If the latter, would you suggest any alternative questions that might be less patronizing / more effective?
It's comments like these that in high school made me avoid calculus. Just wanted to let you know that you are discouraging. The youngsters reading this that are still developing their critical thinking skills are being scared away because of your projections. Frame it different, take responsibility for your inadequacies.
It didn't strike me as discouraging at all. Discouraging would be something like "QM is so hard that 80% of people reading this are too stupid to learn it" (which I don't think is true, FWIW, so don't be discouraged by that)
Just because youngsters don't have critical thinking skills does not mean they will read words that aren't even there. If anyone does that, it's on them, the reader, and no psycho-analytical word smithing will fix that.
OK. If you are a student reading this then, well, firstly I'm not at all sure you're feeling discouraged from learning about the nature of reality and potentially world-changing computing frontiers because someone on the internet said it was a hard subject! But if you were, please don't be. Here's why.
Firstly, a lot of incredibly valuable and interesting things do require a bit of concentration and effort. I'm sure you know this.
But there are reasons to be optimistic! Here are some things to do:
1. Stay calm! Don't give up.
2. It's not at all obvious how to read technical stuff to start off with. Basically, the secret is to read the same paragraph a LOT of times! Everyone does that. No-one can understand it by reading it through once like a novel. If you find yourself reading the same paragraph 100 times you're on the right path because it means that you KNOW you haven't quite grasped all the ideas yet, and so you are becoming your own teacher in a way; setting your own standards for yourself.
3. You've got to be, or become, the sort of person who can concentrate on reading something challenging, in a quiet room. Talking to others is going to help a lot also, but there's a private side to this. You can compare it to training to be on a sports team at a more competitive level. There are going to be times when you're doing fitness training or whatever, and you're on your own, and it hurts because you're exhausted. You know this was always part of the deal.
4. Don't listen to the people who tell you that it's "easy" and "anyone can do it". Yes, anyone can do it in in the sense that everyone has the biological potential to do it (they're human, they have a perfectly good brain). But you know perfectly well, just by looking around at your classmates that some people don't have, or at least don't currently have, the attitude that's going to let them do it. You don't have to be weird; you just need to let one side of your personality be a studious side, occupying some fraction of your time.
Could you tell me if I violated any of the other guidelines / what else I have done that is likely to lower the quality of discussion?
Not sure if this is one that I might have violated here, but I don't think I agree with the guideline saying not to use HN for "ideological battle". That seems to need a clear definition of what "ideology" is, and even then it seems to risk ruling out many important contributions to HN, so I cannot promise to uphold that guideline unless it can be clarified, and possibly not even then.
You can't give precise definitions to any of the terms in the guidelines and it would be a huge mistake to try. All that an attempted formalization would do is create loopholes to be exploited, and then make moderation harder because people would excuse themselves with "it's technically not against the rules". The rules aren't technical. HN is a spirit-of-the-law place, not a letter-of-the-law place: https://hn.algolia.com/?dateRange=all&page=0&prefix=false&qu.... Here's a version of this point from 6 years ago: https://news.ycombinator.com/item?id=7606756
In practice there is an easily observable difference between how people use the site for curious conversation and how they use it for political/ideological battle. The former goes with openness, respect, and exchange of information. The latter goes with being aggressive and wanting to defeat, not hear, the other side. The former produces comments that are unpredictable and fresh; the latter produces comments that are repetitive and nasty.
I can see why you would think that. However, consider the following points:
1. One of the authors is/was[1] one of the most well known experts on quantum computing, and he literally wrote the book on quantum computing.
2. He has written elsewhere on how spaced repetition really helped him understand new disciplines and read journal papers.
So while you may not like spaced repetition, think twice before saying "unhelpful dumbing down", given that it really helped him, and he's very clearly not a dumb person.
There's no harm in simply saying it doesn't work for you. I suggest you examine the need to justify that by making broad statements.
Perhaps there's more to the Rust/Mozilla story that I don't know of, but going from the example you gave and connecting it to making things approachable to minorities is a giant leap I'm having trouble fathoming.
And while the statement is annoying, I did not find it in the least patronizing. I don't doubt that it helps some people, and I think you need to realize that not all books are written for you, and that there likely won't be any book that is good for everyone. If you don't like it, find another book - don't expect the world to cater to you.
When it comes to technical books, particularly math/physics text books, everyone has his/her own opinion and that's OK. There's no shortage of people who hate math books that give too many examples ("Just give me the theorems, proofs, and maybe one example!"), and there's no shortage of people who want examples and hate books that are "theorems/proofs". The same goes for pretty plots, color coding important theorems, etc. Yet not once in my time in academia and beyond did I hear someone say "These distracting elements and examples are dumbing things down and are patronizing, and it's because they're trying to appeal to women and minorities!"
I really think you need to introspect about your world view that led you to these conclusions. You're being triggered, and you need to own your reactions.
> Quantum computing and quantum mechanics is hard and involves sophisticated concepts.
Although I didn't study quantum computing, I have done plenty of non-relativistic quantum mechanics at the grad level. It's hard for only two reasons:
1. Lots of introductory books start off with calculus-heavy problems (infinite square wells, harmonic oscillators, hydrogen atom, etc).
2. It differs from real world experience.
Plenty of people have advocated that item 1 above is the problem, and it is not a good way to teach QM. You get lost in the calculus and don't focus on the QM. There are plenty of advocates (e.g. David Mermin) who think QM should first be taught using spin, because it involves no calculus, and the linear algebra is necessary (and not sophisticated). Almost all, if not all, the fundamentals of QM can be taught that way, and it's not that hard. Certainly a lot easier than much of your introductory physics material (mechanics, EM, etc).
[1] I say "was" because he has left the quantum computing research world.