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I'm Scott Aaronson, quantum computing/computational complexity researcher. AMA

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Re: I'm Scott Aaronson, quantum computing/computational complexity researcher. AMA

#261

Post by ScottAaronson »

vymague wrote: post #160
ScottAaronson wrote: post #59

Earlier quoted context omitted.

I already answered that in another comment, but briefly: Waterloo/Perimeter, Caltech, MIT, Berkeley, U. Maryland, Singapore, Oxford, Cambridge, Bristol, CWI Amsterdam, Hebrew University, Tsinghua, UTS Sydney, McGill/Montreal, LRI Paris, and don't count out UT Austin -- we're planning to expand a lot! And many, many other places have at least one or two people in the field.

How about Germany? It seems people doing optics here like to connect their research to quantum computing.

Yes, there's some great stuff going on at the Max Planck Institute for Quantum Optics outside Munich.

Also the groups in Innsbruck and Vienna in Austria.

Re: I'm Scott Aaronson, quantum computing/computational complexity researcher. AMA

#262

Post by YeGoblynQueenne »

ScottAaronson wrote: post #231
hirundo wrote: post #158

Hi Scott, I'm astounded by the accomplishment of AlphaZero in quickly becoming a chess master without chess specific programming. Could a program of the same kind be adapted to infer or deduce the rules of chess from a large set of valid games? Or is that a different kind of problem? If so, could it be adapted to learn the rules when we're not clear on them either, like those for the games of love or politics?

You should probably wait for an AMA with someone who's actually an expert in AI, and ask them this question. Since you asked me, though, I did a quick Google search and found the following paper: https://arxiv.org/pdf/1711.09667.pdf where indeed they use machine learning to induce the rules of chess from a large number of played games (and then learn to play better than any human). It doesn't surprise me at all that…

>> where indeed they use machine learning to induce the rules of chess from a large number of played games (and then learn to play better than any human).

They didn't induce the rules of chess! What they did was learn an evaluation function for chess moves, from scratch, i.e. without giving it the rules or any hand-crafted features.

So they learned a classifier for good/bad board states, which was later used in an alpha-beta minimax search. However, the classifier didn't learn the rules of the game, only a mapping from board positions to labels, good/bad. This is not made explicit in the text, but minimax typically has a rule-base to generate moves as successor states for the search; so the rules of the game were hand-crafted, but did not contribute to the learning of the evaluation function.

It's extremely hard to induce a set of rules with neural nets, or indeed any statistical machine learning algorithm. I mean, imagine representing the rules of chess as a function; let alone trying to learn that function from data.

(Full disclosure: I study algorithms that learn rules from data; they're not neural nets).

Re: I'm Scott Aaronson, quantum computing/computational complexity researcher. AMA

#263

Post by ScottAaronson »

henryaj wrote: post #241

Do you have any thoughts to offer on the "culture wars", especially the way you were treated by the online mob when you wrote about your personal struggle with your sexual identity[0,1]? 0. http://slatestarcodex.com/2015/01/01/untitled/ 1. https://www.scottaaronson.com/blog/?p=2091#comment-326664

Dude, if you'd just asked me a more specific question, you could surely have baited me into commenting on this or that culture war issue. Since you asked a general question, though, I'll simply answer with the generality that I wish we could all make more of an effort to show empathy for each other's problems, and (as I said on the podcast) carefully articulate where we agree and disagree with each other rather than just flinging 140-character excrement.

OK, I'll also give you a few links. Here's my Quora answer about what it felt like to be widely attacked on social media, for trying to host a conversation about gender and teenage nerdery that got past platitudes to the roots of people's feelings:

https://www.quora.com/What-was-it-like-for-you-to-be-widely-...

Second, here's my friend Sarah Constantin's blog post about the changing nature of social media, the one I mentioned in the podcast:

https://srconstantin.wordpress.com/2016/11/27/hiding-in-plai...

Third, here's a recent post called "On Culture War Bubbles," from the blog "Thing of Things":

https://thingofthings.wordpress.com/2018/06/27/on-culture-wa...

This is much easier said than done, but as Ozy writes in that post, may we all be granted the mental strength to ignore culture war bullshit, until and unless we decide with the rational parts of our brains that it's important or worth responding to.

Re: I'm Scott Aaronson, quantum computing/computational complexity researcher. AMA

#264

Post by YeGoblynQueenne »

dreamcompiler wrote: post #238
hirundo wrote: post #158

Hi Scott, I'm astounded by the accomplishment of AlphaZero in quickly becoming a chess master without chess specific programming. Could a program of the same kind be adapted to infer or deduce the rules of chess from a large set of valid games? Or is that a different kind of problem? If so, could it be adapted to learn the rules when we're not clear on them either, like those for the games of love or politics?

Most of the rules of chess are trivial and thus should be deducible from observing less than one complete game. Rare things like castling might take a couple of games. Love and politics have rulesets that are many orders of magnitude more complex; so complex that we don't even know how to write them all down.

>> Most of the rules of chess are trivial and thus should be deducible from observing less than one complete game. Rare things like castling might take a couple of games.

You'd think so. Try googling "chess rules induction".

Re: I'm Scott Aaronson, quantum computing/computational complexity researcher. AMA

#265

Post by ScottAaronson »

erdevs wrote: post #245

I'd just first like to say that I love reading your work. I'm always delighted when I see an update on Shtetl-Optimized and I admire how you are both simultaneously rigorous and funny in your papers and posts. Your PnP survey stands out in my mind as a truly fun and insightful read in particular. Two questions: 1. Any meaningful updates you'd make to the PnP survey today? 2. As a total aside, I'm curious for your tho…

1. The P vs. NP survey is only 2 years old, so all the edits I'd make to it now would be rather minor ones: for example, including some more recent circuit lower bounds of Ryan Williams and others, some more no-go results for Geometric Complexity Theory, and Raz and Tal's BQP vs. PH breakthrough (which required a new circuit lower bound, though not of a kind that can evade the natural proofs barrier).

2. See here for my answer to someone who asked me for my thoughts on blockchain just a couple weeks ago: https://www.scottaaronson.com/blog/?p=3861#comment-1768247

Re: I'm Scott Aaronson, quantum computing/computational complexity researcher. AMA

#266

Post by ScottAaronson »

ahelwer wrote: post #185

Hey, Scott! Love your book, Quantum Computing Since Democritus. There is one section which confused me, in the Quantum chapter ( https://www.scottaaronson.com/democritus/lec9.html ). I have two questions: 1) You say applying the unitary operation is the quantum analogue of "taking a coin and flipping it" - what do you mean by this? Could we think of, for example, a pair of slits as applying this transformation on a p…

1) Yes, a unitary transformation like the Hadamard gate maps the state |0> to |0>+|1>, while mapping |1> to |0>-|1>. In either case, if you then just measured immediately in the {|0>,|1>} basis without doing anything else, you'd see |0> or |1> with equal probabilities, so it would have the effect of a coin flip. But of course, in other cases---e.g., if you measured in a different basis, or if you applied the Hadamard to a state that wasn't just a |0> or |1> basis state---you could see that Hadamard is not just a coin-flipping transformation, because it's able to produce interference.

2) When we talk about the different "paths" that contribute to a given amplitude, it's just a fancy way of saying that we can organize the matrix multiplications in such a way that the amplitude we want is a giant sum. So for example, suppose we apply Hadamard twice in sequence to the initial state |0>. The first Hadamard maps |0> to (|0>+|1>)/sqrt(2). The second Hadamard maps |0> to (|0>+|1>)/sqrt(2) and |1> to (|0>-|1>)/sqrt(2). So by linearity, it maps (|0>+|1>)/sqrt(2) to

((|0>+|1>)/sqrt(2) + (|0>-|1>)/sqrt(2))/sqrt(2) = (1/2+1/2)|0> + (1/2-1/2)|1>.

So in this case, we could say that there are "two paths leading to |0>," both of which contribute 1/2 to its final amplitude (so that the amplitude is 1). There are also "two paths leading to |1>," but one contributes 1/2 to its amplitude and the other contributes -1/2, so the two contributions interfere destructively and the final amplitude of |1> is 0.

This is sometimes called the "Feynman" or "sum-over-paths" picture of quantum mechanics. As you can see, though, it's just a different way of looking at exactly the same math, namely multiplication of matrices and vectors.

So then why use the sum-over-paths picture at all? Well, a few reasons: physicists like it because it often gives them more insight into what's going on, into what are the more and less important contributions to a given process, and it can also make calculations easier. Meanwhile, computer scientists like the picture because it lets us simulate a quantum computer by a classical computer, still using exponential time but now using only a linear amount of memory, rather than the exponential amount of memory we'd need if we tried to store all 2^n amplitudes at once.

Re: I'm Scott Aaronson, quantum computing/computational complexity researcher. AMA

#267

Post by bloone »

Hey there Scott!

I just wanted to say I wrote a student-paper on quantum computational complexity last year and I felt like your papers made up almost 90% of my references. Thank you for making my learning about the subject possible!

On to my question: I'm working on a capstone project right now that's using quantum computing to create a small video-game. I'm using the 5-qubit quantum experience from IBM and I was wondering if you had any cool ideas/suggestions for small game experiences that could use actual quantum computing resources to teach people about the properties of quantum mechanics?

Thanks again for all your work in understanding the quantum world, Scott.

Re: I'm Scott Aaronson, quantum computing/computational complexity researcher. AMA

#268

Post by ScottAaronson »

code_coyote wrote: post #136

Hello, As for "careers in science", what can someone later in life (I just turned 60, can't believe it) still do? I have a CS degree from ages ago, and have a scientific mindset (runs in my family, e.g., my sister was a research scientist [mathematician] before retirement). I don't want to retire anytime soon. But I'm unlikely to get into grad school. I can take MOOCs of course, and do. My interest in science tends t…

I admire your determination to start a scientific career at age sixty! I once faced the "converse" problem---how to start doing research at age 14 or 15, before I'd found any mentor to help me---and it was one of the great revelations of my life that, at least in theoretical fields, the barriers standing in the way are more internal than external. So long as you have the time, and enough income to live off, you can start reading textbooks and arXiv papers. You can email the authors your questions. You can go to conferences, with or sometimes without registering (just don't tell anyone I said so ;-) ). You can sit in on classes at a nearby university (ask the professor; most are fine with it). You can talk to the professors. You can start working on a problem that interests you. If you get somewhere, you can write it up and submit it to a conference or journal. You can offer your services as a research assistant. The gates are open.

Of course there's a chicken-and-egg problem here, where the stronger your research record, the more busy researchers will want to talk to you, and the more they'll talk to you, the stronger you'll be able to make your record. Just like with dating or anything else, I guess, it does take persistence to break this cycle. :-)

And of course, you'll need to be considerate of people's time, and you'll need to decline to take it personally if some people are too busy to answer you. Just plow ahead and ask others.

Lastly, let me strongly suggest finding some other people who started their research careers later in life, and asking their advice. They'll surely be able to think of things I didn't!

Re: I'm Scott Aaronson, quantum computing/computational complexity researcher. AMA

#269

Post by ScottAaronson »

erostrate wrote: post #220

Hi Scott There are non-quantum physical systems that exhibits positive and negative amplitudes and interference. Can I factor large numbers by throwing rocks in a lake and measuring the water height at the right place? Why not?

See this previous answer: https://news.ycombinator.com/item?id=17428675

Re: I'm Scott Aaronson, quantum computing/computational complexity researcher. AMA

#270

Post by bariswheel »

stcredzero wrote: post #190
ScottAaronson wrote: post #140

Earlier quoted context omitted.

A quantum computer is a device that exploits constructive and destructive interference among exponentially many amplitudes , which are numbers that are closely related to probabilities but can be positive, negative, or even complex. If you feel that sentence wasn't clear enough, and it would take at least a few more paragraphs to flesh it out ... well, duh, what did you expect? :-D For a SLIGHTLY longer account, see…

Here's my attempt at a two sentence over-over-over simplification that at least gets people away from the "magic bit-sting that contains your answer." (It also harkens back to an old Einstein quote, so may be attractive to science writers.) Quantum computing is a technique that lets you sample a problem's answer-space using "loaded dice," such that the problem's correct answers correspond with probability spikes in y…

Do you mean all the possible solutions to a problem when you say 'answer space' ?
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