2

My question is definitely regarding quantum-speedup but the quantum-speedup tag is confined to algorithms... and my question is definitely not on algorithms. So, this is just my best shot at tagging.

This article in Physics World discusses quantum speedup and makes some pretty provocative statements (examples below).

It also tells me that people in a forum like this one might feel as follows: “Some feel that this debate about the “how” of quantum computation is a red herring. “Researchers attending most conferences in quantum computing never mention these issues, or only in discussions over beer”.

Here are some of those "provocative statements".

“None of the explanations for how quantum computers achieve speed-up is universally accepted.”

“If it’s not from the vastness of Hilbert space, not from entanglement and not interference, then what? “As far as I am aware, right now it’s pretty silent in the theatre where this question is played out – that’s because the main candidates are all dead...”

Here are two specific questions. As a worker in this field, does the following statement from the 2014 Physics World article match your own perception here in 2018? If not, what are the favored candidates today? And again, this is not a question about speedups obtained via algorithmic refinement. Why exclude algorithmic refinement? See "Footnote".

"Deutsch’s notion of quantum parallelism has stuck – the standard explanation in popular descriptions of quantum-computing speed-up is still that massively parallel computation takes place..."

Footnote: Why exclude algorithmic refinements? Again from that article: “Designing good quantum algorithms is a very difficult task,” Van den Nest agrees. “I believe this task could be made lighter if we were to arrive at a systematic understanding of the possible ways to move from classical to quantum computing” – in other words, if we had a better grasp of which aspect of quantum physics the advantages ultimately stem from."

I just noticed that link is going be unfamiliar (to me too). So I vetted it just a little. The home page says: "Dr. Franco Nori is a RIKEN Chief Scientist, heading the “Theoretical Quantum Physics Laboratory” at the “Cluster for Pioneering Research” at Riken, Saitama, Japan. He is also at the University of Michigan, Ann Arbor, USA"

GRSmith
  • 21
  • 3
  • It is not just nonzero entanglement because of Gottesman-Knill theorem. Similarly that seems like the way to approach this kind of question. What can you do classically? If you can do some aspect classically, then it cannot be the cause of speedup, at least not by itself. – AHusain Oct 18 '18 at 20:05
  • 2
    What is your question? The only question mark I found in your article is inside a quote. – user1271772 No more free time Oct 18 '18 at 21:54
  • 1
    This post needs a bit of work, I think. It seems potentially opinion- based, and on top of not asking a definite question (as user1271772 notes), is very close to asking multiple questions. – Niel de Beaudrap Oct 19 '18 at 06:14
  • Welcome to Quantum Computing SE! Just to let you know, we're not a site for discussions as you'd have in a traditional 'forum' and instead we're designed for asking and answering specific, objective questions, If you want to take the [tour] to get what we're about in more detail, feel free to do so and if you [edit] this post so it contains a question we can objectively answer (as opposed to something to discuss), it'll automatically get put in a reopen queue. In the meantime, I'm putting this on hold in order to help prevent opinionated arguments that might not say what you're looking for – Mithrandir24601 Oct 19 '18 at 07:20
  • The same things can often be said about design of classical algorithms. There is no systematic understanding of fast classical algorithms. In fact proving general results about algorithmic speed ups is not easy. Also, I don't think that the argument made in the article about entanglement is in good faith. The paper by Van den Nest quoted in the article clearly states that the problem arises because we don't have good ways to measure multipartite entanglement. The recent paper "Quantum advantage with shallow circuits" gives an explicit instance where multipartite entanglement helps. – biryani Oct 19 '18 at 10:52
  • After numerous edits today I think I am finally done rewording this. – GRSmith Oct 19 '18 at 21:51
  • Do I understand correctly that your question is about our opinions about how quantum computation is perceived by the public / presented in popular articles? – Niel de Beaudrap Oct 19 '18 at 23:47
  • The article's use of the word 'popular' is not in reference to general public opinion. Instead, it is used in reference to opinions (circa 2014) among physicists working in research, industry and education who specifically contemplate the source of speedups obtainable in quantum computing. I realize yours is not a forum for physicists. But you too work in the realm of quantum computing. So, I am assuming (perhaps wrongly) that some of you occasionally contemplate the underlying quantum physics responsible for the speedups seen in quantum computing. – GRSmith Oct 20 '18 at 05:52
  • Such as: parallelism, entanglement, interference, contextuality... – GRSmith Oct 20 '18 at 06:06
  • Also... I just now realized that the name of that magazine might be unfamiliar... and may unfortunately sound like a pop-sci publication. Instead, here is what Wikipedia says: "Physics World is the membership magazine of the Institute of Physics, one of the largest physical societies in the world. It is an international monthly magazine covering all areas of physics, pure and applied, and is aimed at physicists in research, industry, physics outreach, and education worldwide" – GRSmith Oct 20 '18 at 06:20
  • @GRSmith: Speaking for myself, not only do I think about the speedup, but it is something which motivates specific questions I have worked on. But your question is basically about our opinions about the common opinion in the field, on a topic which (as the article suggests) is not a subject of robust academic discussion. You're asking us to guess about what other people think about a problem which is not entirely well-defined, and this sort of polling isn't really what StackExchange is for IMO. (And: what if furthermore someone considered that popular opinion slightly misinformed?) – Niel de Beaudrap Oct 20 '18 at 09:57
  • That's very close to an answer satisfying my question. But, let me make certain I understand you. Your first sentence seems to be a direct response to something I said. Would it be correct then to use the same words I used, or are you changing my meaning? Did you mean: "Speaking for myself, not only do I think about the [underlying quantum physics responsible for the] speedup, but it is something which motivates specific questions I have worked on." If so can you elaborate a little? – GRSmith Oct 20 '18 at 16:01
  • coming from the reopen queue: I think that this question needs more edits before being reopened. There are probably interesting things in it that are worth asking, but stackexchange is not well suited for asking people's subjective opinion about things. For example, statements like "As a worker in this field, does the following statement from the 2014 Physics World article match your own perception here in 2018?" make the question feel markedly off topic on SE. There are also too many topics/questions being asked. – glS Oct 25 '18 at 12:17
  • I would suggest to make the wording less prone to personal opinions, and also possibly to break up the question into multiple posts, asking a single specific question in each – glS Oct 25 '18 at 12:17

0 Answers0