
An Introduction to Quantum Computing, Without the Physics - lainon
https://arxiv.org/abs/1708.03684
======
daxfohl
The article on QC I got the most out of:
[http://www.scottaaronson.com/blog/?p=208](http://www.scottaaronson.com/blog/?p=208)

Very visual example of how Shor's algorithm works to solve factoring. Nothing
more than basic arithmetic required.

The big takeaway for me was, it's not just "try every combination at once" as
per pop lit on the subject. QC doesn't really do that. To get QC to work any
better that traditional for any task, you need to get lucky and stumble across
an algorithm that QC can excel at for that task. Just from reading Scott
Aaronson's article, it seems likely that most tasks simply don't have a QC
optimization, so perhaps QC won't change much at all. (Well, except
cryptography, which may change everything...)

~~~
chadcmulligan
Yes, this was a bit of a surprise for me to - "In fact, in general solving NP-
hard problems in polynomial time with quantum computers is not believed to be
possible"

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s-macke
Consider these two simulators, if you want to try the examples in the paper:

1\. [https://www.research.ibm.com/ibm-q/](https://www.research.ibm.com/ibm-q/)

This is IBM Quantum experience. Click on "experiment" to start. It has a nice
tutorial.

2\. [http://algassert.com/quirk](http://algassert.com/quirk)

I like this one much better, because you can see the internal state of the
machine at any moment. And it has much more options and is much faster.

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Strilanc
After quickly skimming it it seems well done. Leans towards mathematical
rigor, which may not be ideal for some people. On the other hand, it'd be
pretty hard to avoid math: quantum computing is linear algebra incarnate.

The only thing that caught my eye as off was totally minor. They say the many-
controlled-Z gate used by Grover's algorithm can be done in O(n^2) constant-
sized gates with an argument-by-reference, but with that type of argument you
might as well give the tight bound of Θ(n).

~~~
msla
It's possible to have a gentle ramp-up on the math content while learning
quantum mechanics. "The Theoretical Minimum" by Susskind and Hrabovsky is
structured like that: They teach you the math as part of, and motivated by,
teaching the physics, and the books don't lag or resort to hand-waving.

[https://en.wikipedia.org/wiki/The_Theoretical_Minimum](https://en.wikipedia.org/wiki/The_Theoretical_Minimum)

~~~
tmccrmck
Note: Susskind has a follow up - _Quantum Mechanics: The Theoretical Minimum_.

[https://www.goodreads.com/book/show/18210750-quantum-
mechani...](https://www.goodreads.com/book/show/18210750-quantum-mechanics)

~~~
msla
I should have been clearer that I was referring to both books in the series
with my remarks.

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CacheThrasher
Thanks for this, I have been looking for a good introduction to Quantum
Computing. I haven't actually read it yet, but this looks promising.

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indigo0086
I've been meaning to get into it but someone recommended me this series on
youtube
[https://www.youtube.com/watch?v=X2q1PuI2RFI&list=PL1826E60FD...](https://www.youtube.com/watch?v=X2q1PuI2RFI&list=PL1826E60FD05B44E4)

~~~
tmccrmck
_Quantum Computation and Quantum Information_ by Nielsen and Chuang is the
standard introduction to quantum computing. Besides that, you can find some
old CS191 Vazirani lectures on the internet.

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epx
Hope I am retired before it's mainstream :)

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Koshkin
> _Without the Physics_

Well, is there much "physics" in (theoretical) quantum physics anyway? It's
pretty much all math - just like in this paper!

~~~
pvg
Maths doesn't have to agree with physical experiments and observation.

