6 ms·

In what sense is quantum computing a science?

26 points by EntICOnc 4y ago

prettyStandard 4y ago
I just don't understand how Quantum Computing could work. It seems like the premise is QC defies the premise of QM.
- meltyness 4y ago
  It's about - finding and implementing in hardware an "embedding" which solves certain classes of problems efficiently, especially for which there is no known "efficient" process otherwise. - finding an elegant way of describing those classes of problems and - routes for identifying them. I think [0] Schwartz-Zippel as applied to Polynomial Identity Testing is an instructive example where using noise as a computational resource improves efficiency. [0] https://en.wikipedia.org/wiki/Schwartz%E2%80%93Zippel_lemma https://en.wikipedia.org/wiki/Schwartz%E2%80%93Zippel_lemma
- halpmeh 4y ago
  QC works by the exploiting statistical properties of an algorithm to infer something about the subject through quantum computation. Writing quantum algorithms is hard because you can rarely write your algorithm in a way that directly deals with the property you want information on. Rather, you need to write an algorithm that yields your desired information as a biproduct of some other computation.
- jerf 4y ago
  The premise of QC is that QM is essentially correct, to the n'th degree. We know that QM is "wrong" in the sense that it isn't the Grand Unified Theory of Everything because it does not merge properly with Relativity, but we respect the Correspondence Principle to hold for it in the relevant domain. Ignoring the substantial engineering challenges, if QC doesn't work, we would learn something very interesting about our world in how it breaks, because any break would represent a deviation between the predictions of QM and reality, something we desperately need to get to the next level of theory. Contrary to what some people might think, physicists would be giddy over a clean, lab-reproducible, engineering-type break in QM. They are starved for data right now. To be able to push a button and reproduce it is an almost impossibly beautiful dream. Almost for that reason, I expect our problems in QC to remain firmly in the engineering domain, and that no matter how many qubits we manage to deploy they will obstinately perfectly conform to QM theory.
  - vba616 4y ago
    I'm completely unqualified to hold an opinion, but it seems so intuitive to me that quantum computing is theoretically sound but impossible in practice because error correction will scale exponentially in difficulty. Experts are clearly more optimistic, especially Scott Aaronson who is often mentioned on HN, but I can't get past a couple of simplistic, non-mathematical objections. One is that it seems already like quantum computing is on a different trajectory than classical computing. If it was an analogous engineering problem, why haven't we already gotten much farther? The other is that it just seems like a matter of symmetry. Quantum computing, even if it's not all powerful, seems like a "cheat code" for reality, and an inability to practically exploit it seems to me like balancing it out. I believe in a vague heuristic that reality has no "thread" that can be pulled to unravel everything. I guess the counter to these vague feelings are that you could've said the same stuff about nuclear fission/fusion and any technology based on quantum theory. So I'm not that confident in my opinion, but I'm still seeking an understandable reason why one should be optimistic. Nothing I've read by experts translates their feelings to my understanding. The sort of situation that seems intuitive to me, I don't see why it would result in any earthshattering violation of theory either, as we'd just approach an asymptote forever. P.S. I have a similar attitude towards practical fusion power for somewhat similar reasons, so that's evidence it's an attitude problem more than anything.
    - K0balt 4y ago
      QC is already a practical computing system that is solving “practically unsolvable” problems. It’s just not highly publicized because much of the work is relevant to state security. The field is a bit farther along than one would infer from contemporary information and publicly published papers. If you think about it even a little, it is almost axiomatic to the intelligence/security world that a machine that could break much known encryption in human relevant timeframes would obviously be being developed under a shroud of secrecy at the bleeding edge. It is far too important to be able to manage the implications of any significant breakthroughs potentially years before public release. QC is not magic and there are effective counter strategies. But standards take time to implement and the well being of society demands a that the impacts of QC be mitigated through control of the tech and the information around it. Fortunately, the tech required so far keeps access to the computing resource somewhat restricted, and organizations that cooperate with governments control it so far. For most people, the important thing to keep in mind is that everything now shielded by many forms of encryption will be trivially readable in the foreseeable future. Truly sensitive data stored long term should be moved to Q hard algorithms and old versions destroyed as possible (easier said than done in many cases)
halpmeh 4y ago
Quantum computers are a science in the same way all of mathematics is a science. In math, you create a set of axioms and build logical structures on top of them. In quantum computing, the existence of a qubit and its operations are the axioms. Trying to coin a meaningless phrase like “design science” and only mentioning math indirectly via Arabic numerals seems wrong.
- sidlls 4y ago
  This seems inaccurate. Engineering isn't a branch of mathematics: it relies on empirical results ("observations") and theory from physics (which also is empirical). Mathematics is not science. Engineering is science. Engineering (huge simplification, here) is essentially one experiment after another.
  - xyzzyz 4y ago
    No, the parent is exactly correct. Research in quantum computing has been mostly mathematical, and it predated any practical development of useful physical implementations of quantum computing. Quantum computing as a field does not depend on empirical results any more than study of Turing machines depends on properties of physical tapes.
  - coef2 4y ago
    I thought neither mathematics nor engineering is strictly science. Engineering utilizes scientific knowledge to solve complex problems, but its purpose isn't to make scientific discoveries through hypothesis testing. It's interesting, though, that new artificial scientific disciplines (e.g., theory of how quantum computing works) occasionally spin out of engineering projects.
    - deleted 4y ago
      [deleted]
    - rishflab 4y ago
      Agreed, engineering is about building stuff, not making discoveries about how the universe/existence works. Engineering often results in scientific discoveries but this is incidental.
IIAOPSW 4y ago
In what sense is computer science a science?
julienreszka 4y ago
It makes predictions and they have some degree of accuracy
deterministic 4y ago
“Computer Science” has nothing to do with computers or science. It should be called Computation instead.
- lioeters 4y ago
  Computer Science Is Not About Computers, Any More Than Astronomy Is About Telescopes - https://quoteinvestigator.com/2021/04/02/computer-science/ https://quoteinvestigator.com/2021/04/02/computer-science/ Computer Science Is Not a Science - https://cacm.acm.org/magazines/2013/1/158757-computer-science-is-not-a-science/fulltext https://cacm.acm.org/magazines/2013/1/158757-computer-scienc...

26 points by EntICOnc 4y ago

prettyStandard 4y ago

I just don't understand how Quantum Computing could work. It seems like the premise is QC defies the premise of QM.

meltyness 4y ago
It's about - finding and implementing in hardware an "embedding" which solves certain classes of problems efficiently, especially for which there is no known "efficient" process otherwise. - finding an elegant way of describing those classes of problems and - routes for identifying them. I think [0] Schwartz-Zippel as applied to Polynomial Identity Testing is an instructive example where using noise as a computational resource improves efficiency. [0] https://en.wikipedia.org/wiki/Schwartz%E2%80%93Zippel_lemma https://en.wikipedia.org/wiki/Schwartz%E2%80%93Zippel_lemma
halpmeh 4y ago
QC works by the exploiting statistical properties of an algorithm to infer something about the subject through quantum computation. Writing quantum algorithms is hard because you can rarely write your algorithm in a way that directly deals with the property you want information on. Rather, you need to write an algorithm that yields your desired information as a biproduct of some other computation.
jerf 4y ago
The premise of QC is that QM is essentially correct, to the n'th degree. We know that QM is "wrong" in the sense that it isn't the Grand Unified Theory of Everything because it does not merge properly with Relativity, but we respect the Correspondence Principle to hold for it in the relevant domain. Ignoring the substantial engineering challenges, if QC doesn't work, we would learn something very interesting about our world in how it breaks, because any break would represent a deviation between the predictions of QM and reality, something we desperately need to get to the next level of theory. Contrary to what some people might think, physicists would be giddy over a clean, lab-reproducible, engineering-type break in QM. They are starved for data right now. To be able to push a button and reproduce it is an almost impossibly beautiful dream. Almost for that reason, I expect our problems in QC to remain firmly in the engineering domain, and that no matter how many qubits we manage to deploy they will obstinately perfectly conform to QM theory.
- vba616 4y ago
  I'm completely unqualified to hold an opinion, but it seems so intuitive to me that quantum computing is theoretically sound but impossible in practice because error correction will scale exponentially in difficulty. Experts are clearly more optimistic, especially Scott Aaronson who is often mentioned on HN, but I can't get past a couple of simplistic, non-mathematical objections. One is that it seems already like quantum computing is on a different trajectory than classical computing. If it was an analogous engineering problem, why haven't we already gotten much farther? The other is that it just seems like a matter of symmetry. Quantum computing, even if it's not all powerful, seems like a "cheat code" for reality, and an inability to practically exploit it seems to me like balancing it out. I believe in a vague heuristic that reality has no "thread" that can be pulled to unravel everything. I guess the counter to these vague feelings are that you could've said the same stuff about nuclear fission/fusion and any technology based on quantum theory. So I'm not that confident in my opinion, but I'm still seeking an understandable reason why one should be optimistic. Nothing I've read by experts translates their feelings to my understanding. The sort of situation that seems intuitive to me, I don't see why it would result in any earthshattering violation of theory either, as we'd just approach an asymptote forever. P.S. I have a similar attitude towards practical fusion power for somewhat similar reasons, so that's evidence it's an attitude problem more than anything.
  - K0balt 4y ago
    QC is already a practical computing system that is solving “practically unsolvable” problems. It’s just not highly publicized because much of the work is relevant to state security. The field is a bit farther along than one would infer from contemporary information and publicly published papers. If you think about it even a little, it is almost axiomatic to the intelligence/security world that a machine that could break much known encryption in human relevant timeframes would obviously be being developed under a shroud of secrecy at the bleeding edge. It is far too important to be able to manage the implications of any significant breakthroughs potentially years before public release. QC is not magic and there are effective counter strategies. But standards take time to implement and the well being of society demands a that the impacts of QC be mitigated through control of the tech and the information around it. Fortunately, the tech required so far keeps access to the computing resource somewhat restricted, and organizations that cooperate with governments control it so far. For most people, the important thing to keep in mind is that everything now shielded by many forms of encryption will be trivially readable in the foreseeable future. Truly sensitive data stored long term should be moved to Q hard algorithms and old versions destroyed as possible (easier said than done in many cases)

halpmeh 4y ago

Quantum computers are a science in the same way all of mathematics is a science. In math, you create a set of axioms and build logical structures on top of them. In quantum computing, the existence of a qubit and its operations are the axioms. Trying to coin a meaningless phrase like “design science” and only mentioning math indirectly via Arabic numerals seems wrong.

sidlls 4y ago
This seems inaccurate. Engineering isn't a branch of mathematics: it relies on empirical results ("observations") and theory from physics (which also is empirical). Mathematics is not science. Engineering is science. Engineering (huge simplification, here) is essentially one experiment after another.
- xyzzyz 4y ago
  No, the parent is exactly correct. Research in quantum computing has been mostly mathematical, and it predated any practical development of useful physical implementations of quantum computing. Quantum computing as a field does not depend on empirical results any more than study of Turing machines depends on properties of physical tapes.
- coef2 4y ago
  I thought neither mathematics nor engineering is strictly science. Engineering utilizes scientific knowledge to solve complex problems, but its purpose isn't to make scientific discoveries through hypothesis testing. It's interesting, though, that new artificial scientific disciplines (e.g., theory of how quantum computing works) occasionally spin out of engineering projects.
  - deleted 4y ago
    [deleted]
  - rishflab 4y ago
    Agreed, engineering is about building stuff, not making discoveries about how the universe/existence works. Engineering often results in scientific discoveries but this is incidental.

IIAOPSW 4y ago

In what sense is computer science a science?

julienreszka 4y ago

It makes predictions and they have some degree of accuracy

deterministic 4y ago

“Computer Science” has nothing to do with computers or science. It should be called Computation instead.

lioeters 4y ago
Computer Science Is Not About Computers, Any More Than Astronomy Is About Telescopes - https://quoteinvestigator.com/2021/04/02/computer-science/ https://quoteinvestigator.com/2021/04/02/computer-science/ Computer Science Is Not a Science - https://cacm.acm.org/magazines/2013/1/158757-computer-science-is-not-a-science/fulltext https://cacm.acm.org/magazines/2013/1/158757-computer-scienc...