13 ms·

Learn Quantum Computation

177 points by headalgorithm 6y ago

giantg2 6y ago
Man! I just got this book for Christmas, but I guess I didn't need to... https://www.amazon.com/Quantum-Computation-Information-10th-Anniversary/dp/1107002176/ref=mp_s_a_1_1?dchild=1&keywords=quantum+computation+and+quantum+information&qid=1609370581&sprefix=quantum+com&sr=8-1&pldnSite=1 https://www.amazon.com/Quantum-Computation-Information-10th-...
- xoralkindi 6y ago
  Keep it. You will need it in a parallel universe.
  - nomoreusernames 6y ago
    you should be some sort of survivalist oracle AI. seems useful.
  - giantg2 6y ago
    I don't really need it in this universe - I've realized that I'm a loser and wouldn't benefit from it.
- abdullahkhalids 6y ago
  Nielson and Chuang, while getting quite dated now [1], is still the best introduction to the conceptual framework of quantum computation and information. Its algorithms section though is not very detailed, and I found it difficult to teach my undergrad students from it. The qiskit book gives a nice introduction to the algorithms, and contains all the latest algorithms, for someone wanting to learn the field. [1] it doesn't include a lot of new advances in the past twenty years.
  - ianai 6y ago
    Is there a follow up book to it? Like that you’d recommend, not that they wrote.
  - Escapado 6y ago
    I can vouch for that book too. About 3 years ago I used it as the main text book for a QC course and came back to it multiple times during my master thesis. For me it was just concise enough to stay focused but not get lost every other sentence (unlike 90% of math books I worked through). However the parent is right in that it is a little outdated when it comes to the physical realizations and maybe some algorithmic findings. Anyway it was an invaluable resource for me and I would love a new revision from both authors.
  - nightcracker 6y ago
    There's also https://quantumalgorithmzoo.org/ https://quantumalgorithmzoo.org/.
- nistath 6y ago
  Shor just used this book last semester in MIT’s quantum computing class.
  - waitingkuo 6y ago
    It's opened and free now https://openlearninglibrary.mit.edu/courses/course-v1:MITx+8.370.1x+1T2018/about https://openlearninglibrary.mit.edu/courses/course-v1:MITx+8...
helixc 6y ago
I have a question to the folks who are interested in quantum computation: do you feel getting benefits if you can have direct access to a physical quantum computer? In other words, what hands-on experience you hope to obtain, but cannot make it using a quantum simulator or cloud based quantum programming environment?
- nomoreusernames 6y ago
  haha i am waiting for a smart nerd to answer this. you elegantly said what i thought "but what can i do with it?"
- deleted 6y ago
  [deleted]
- latenightcoding 6y ago
  Just quantum supremacy experiments. Running things on quantum hardware instead of using a simulator will just be slower and more expensive for the foreseeable future.
- narush 6y ago
  I was interesting in quantum computation / programming about a year ago, but failed to really get into it (I'm too dum, I think :)). Mostly, my interest was in understanding the mental model. I learned Golang like 1.5 years ago, and it totally changed how I think about concurrency. I think about interacting processes way different now, as a result - and I was kinda hoping the same thing would happen with ~quantum~. Blarg.
  - dandanua 6y ago
    Quantum mechanics is certainly mind-changing, but it can't explain yet what our world really is. The most popular many-worlds interpretation is very far from complete.
    - tsimionescu 6y ago
      Many-worlds is definitely not the most popular interpretation among practitioners, Copenhagen is by far.
xvilka 6y ago
Haskell purity and now linear types (since GHC 9.0) are better suited for the consequences of quantum effects for computation. For example, the "no-clone" principle. Thus, languages like Quipper[1] are better positioned for such modelling. [1] https://www.mathstat.dal.ca/~selinger/quipper/ https://www.mathstat.dal.ca/~selinger/quipper/
- tsimionescu 6y ago
  I would think that linear algebra and matrix operations as a first class concept would be more useful than modelling the linearity of types.
ketanmaheshwari 6y ago
Just last week I finished a course on Quantum Computing on coursera[1]. I found the idea of true randomness and multiverse really fascinating. However, I could not understand the following and would greatly appreciate if someone could help me out: -- The need for complex numbers in describing a quantum bit. Why do we have to use complex numbers when the system is very much real? What is the real world interpretation? -- The fact that an n-qubit quantum computing system is significantly powerful than classical system because of 2^n states. But, a classical system with n-bits will also have 2^n states, isn't it? [1] https://www.coursera.org/learn/quantum-computing-lfmu https://www.coursera.org/learn/quantum-computing-lfmu
- mhh__ 6y ago
  > Why do we have to use complex numbers when the system is very much real If you don't use complex numbers you end up with a bunch of maths that looks suspiciously like complex numbers. The algebraic properties of complex numbers make it a very natural way to express quantum mechanics. I believe 3Blue1Brown has some good videos on the topic - you really need to learn about complex numbers separately to really see the magic of them (It's largely visual, so it's hard to transmit via text) Edit: The book "Visual Complex Analysis" is very good if you resonate with its approach - I personally simply cannot click with almost any geometry, so it wasn't really for me although I appreciate that it's really very nice.
- nightcracker 6y ago
  > The need for complex numbers in describing a quantum bit. Why do we have to use complex numbers when the system is very much real? What is the real world interpretation? The world isn't "real" (people rightfully find imaginary numbers a bad name, but real is equally bad). Complex numbers show up all over in physics. As to why, who knows? We just model what nature does, and it turns out that complex numbers form a very simple (relatively speaking) accurate model. > The fact that an n-qubit quantum computing system is significantly powerful than classical system because of 2^n states. But, a classical system with n-bits will also have 2^n states, isn't it? A n-bit pure quantum state can be fully described using 2^n complex numbers, and thus have 2^(n+1) degrees of freedom, which is a vastly bigger space than n bits. While quantum amplitudes are distinctly not probabilities (and more powerful), you can think of the difference in state space roughly by comparing the difference of storing one n-bit number v.s. storing one specific probability distribution over all n-bit numbers.
iou 6y ago
Are these the same as the https://quantum.country https://quantum.country people? The styling on the site looks similar?
- kilovoltaire 6y ago
  The list of authors doesn't include Michael Nielsen or Andy Matuschak so I guess not. (Aside: I learned so much from Quantum Country!)
mianos 6y ago
Maybe it is me, the material looks really good, but: Minutes into it the notebooks on the page stop working, mainly due to trivial errors, like missing imports. It is not much use having a 'run' button if you can't run it. The setup is incomplete so you are not going to be running it locally. The introduction to linear algebra assumes you already know abstract algebra.
stared 6y ago
I suggest an alternative first step to quantum computing: hands-on, by playing. Either Quantum Odyssey (https://www.quarksinteractive.com/ https://www.quarksinteractive.com/) - a game purely about quantum circuits. And, up to my best knowledge, the only easy introduction to quantum computing that passes the Scott Aaronson's Minus Sign Test. Another one (full disclaimer: I am a co-founder) is the Quantum Lab (https://quantumflytrap.com/ https://quantumflytrap.com/) - a real-time, install-free, LEGO-like simulation of an optical table with a few entangled photons. Written in Rust + WASM, and goes well beyond "just qubits".
- jonny383 6y ago
  Was the Rust + WASM meant to add any significant value to this marketing, or is it just tech masturbation?
person_of_color 6y ago
What's the ROI on learning this?

177 points by headalgorithm 6y ago

Man! I just got this book for Christmas, but I guess I didn't need to... https://www.amazon.com/Quantum-Computation-Information-10th-Anniversary/dp/1107002176/ref=mp_s_a_1_1?dchild=1&keywords=quantum+computation+and+quantum+information&qid=1609370581&sprefix=quantum+com&sr=8-1&pldnSite=1 https://www.amazon.com/Quantum-Computation-Information-10th-...

xoralkindi 6y ago
Keep it. You will need it in a parallel universe.
- nomoreusernames 6y ago
  you should be some sort of survivalist oracle AI. seems useful.
- giantg2 6y ago
  I don't really need it in this universe - I've realized that I'm a loser and wouldn't benefit from it.
abdullahkhalids 6y ago
Nielson and Chuang, while getting quite dated now [1], is still the best introduction to the conceptual framework of quantum computation and information. Its algorithms section though is not very detailed, and I found it difficult to teach my undergrad students from it. The qiskit book gives a nice introduction to the algorithms, and contains all the latest algorithms, for someone wanting to learn the field. [1] it doesn't include a lot of new advances in the past twenty years.
- ianai 6y ago
  Is there a follow up book to it? Like that you’d recommend, not that they wrote.
- Escapado 6y ago
  I can vouch for that book too. About 3 years ago I used it as the main text book for a QC course and came back to it multiple times during my master thesis. For me it was just concise enough to stay focused but not get lost every other sentence (unlike 90% of math books I worked through). However the parent is right in that it is a little outdated when it comes to the physical realizations and maybe some algorithmic findings. Anyway it was an invaluable resource for me and I would love a new revision from both authors.
- nightcracker 6y ago
  There's also https://quantumalgorithmzoo.org/ https://quantumalgorithmzoo.org/.
nistath 6y ago
Shor just used this book last semester in MIT’s quantum computing class.
- waitingkuo 6y ago
  It's opened and free now https://openlearninglibrary.mit.edu/courses/course-v1:MITx+8.370.1x+1T2018/about https://openlearninglibrary.mit.edu/courses/course-v1:MITx+8...

helixc 6y ago

I have a question to the folks who are interested in quantum computation: do you feel getting benefits if you can have direct access to a physical quantum computer? In other words, what hands-on experience you hope to obtain, but cannot make it using a quantum simulator or cloud based quantum programming environment?

nomoreusernames 6y ago
haha i am waiting for a smart nerd to answer this. you elegantly said what i thought "but what can i do with it?"
deleted 6y ago
[deleted]
latenightcoding 6y ago
Just quantum supremacy experiments. Running things on quantum hardware instead of using a simulator will just be slower and more expensive for the foreseeable future.
narush 6y ago
I was interesting in quantum computation / programming about a year ago, but failed to really get into it (I'm too dum, I think :)). Mostly, my interest was in understanding the mental model. I learned Golang like 1.5 years ago, and it totally changed how I think about concurrency. I think about interacting processes way different now, as a result - and I was kinda hoping the same thing would happen with ~quantum~. Blarg.
- dandanua 6y ago
  Quantum mechanics is certainly mind-changing, but it can't explain yet what our world really is. The most popular many-worlds interpretation is very far from complete.
  - tsimionescu 6y ago
    Many-worlds is definitely not the most popular interpretation among practitioners, Copenhagen is by far.

xvilka 6y ago

Haskell purity and now linear types (since GHC 9.0) are better suited for the consequences of quantum effects for computation. For example, the "no-clone" principle. Thus, languages like Quipper[1] are better positioned for such modelling. [1] https://www.mathstat.dal.ca/~selinger/quipper/ https://www.mathstat.dal.ca/~selinger/quipper/

tsimionescu 6y ago
I would think that linear algebra and matrix operations as a first class concept would be more useful than modelling the linearity of types.

ketanmaheshwari 6y ago

Just last week I finished a course on Quantum Computing on coursera[1]. I found the idea of true randomness and multiverse really fascinating. However, I could not understand the following and would greatly appreciate if someone could help me out: -- The need for complex numbers in describing a quantum bit. Why do we have to use complex numbers when the system is very much real? What is the real world interpretation? -- The fact that an n-qubit quantum computing system is significantly powerful than classical system because of 2^n states. But, a classical system with n-bits will also have 2^n states, isn't it? [1] https://www.coursera.org/learn/quantum-computing-lfmu https://www.coursera.org/learn/quantum-computing-lfmu

mhh__ 6y ago
> Why do we have to use complex numbers when the system is very much real If you don't use complex numbers you end up with a bunch of maths that looks suspiciously like complex numbers. The algebraic properties of complex numbers make it a very natural way to express quantum mechanics. I believe 3Blue1Brown has some good videos on the topic - you really need to learn about complex numbers separately to really see the magic of them (It's largely visual, so it's hard to transmit via text) Edit: The book "Visual Complex Analysis" is very good if you resonate with its approach - I personally simply cannot click with almost any geometry, so it wasn't really for me although I appreciate that it's really very nice.
nightcracker 6y ago
> The need for complex numbers in describing a quantum bit. Why do we have to use complex numbers when the system is very much real? What is the real world interpretation? The world isn't "real" (people rightfully find imaginary numbers a bad name, but real is equally bad). Complex numbers show up all over in physics. As to why, who knows? We just model what nature does, and it turns out that complex numbers form a very simple (relatively speaking) accurate model. > The fact that an n-qubit quantum computing system is significantly powerful than classical system because of 2^n states. But, a classical system with n-bits will also have 2^n states, isn't it? A n-bit pure quantum state can be fully described using 2^n complex numbers, and thus have 2^(n+1) degrees of freedom, which is a vastly bigger space than n bits. While quantum amplitudes are distinctly not probabilities (and more powerful), you can think of the difference in state space roughly by comparing the difference of storing one n-bit number v.s. storing one specific probability distribution over all n-bit numbers.

iou 6y ago

Are these the same as the https://quantum.country https://quantum.country people? The styling on the site looks similar?

kilovoltaire 6y ago
The list of authors doesn't include Michael Nielsen or Andy Matuschak so I guess not. (Aside: I learned so much from Quantum Country!)

mianos 6y ago

Maybe it is me, the material looks really good, but: Minutes into it the notebooks on the page stop working, mainly due to trivial errors, like missing imports. It is not much use having a 'run' button if you can't run it. The setup is incomplete so you are not going to be running it locally. The introduction to linear algebra assumes you already know abstract algebra.

stared 6y ago

I suggest an alternative first step to quantum computing: hands-on, by playing. Either Quantum Odyssey (https://www.quarksinteractive.com/ https://www.quarksinteractive.com/) - a game purely about quantum circuits. And, up to my best knowledge, the only easy introduction to quantum computing that passes the Scott Aaronson's Minus Sign Test. Another one (full disclaimer: I am a co-founder) is the Quantum Lab (https://quantumflytrap.com/ https://quantumflytrap.com/) - a real-time, install-free, LEGO-like simulation of an optical table with a few entangled photons. Written in Rust + WASM, and goes well beyond "just qubits".

jonny383 6y ago
Was the Rust + WASM meant to add any significant value to this marketing, or is it just tech masturbation?

person_of_color 6y ago

What's the ROI on learning this?