5 ms·

Quantum computers don't exist; qubits as they exist today are simply sources of entropy. So every time someone does a big fanfare announcement of this many qubi

Quantum computers don't exist; qubits as they exist today are simply sources of entropy. So every time someone does a big fanfare announcement of this many qubit "computer" I chuckle a bit; ok, you got a bigger "random number generator", cool cool cool :) If you downvote, please also include a link to something that proves a quantum computer exists (outside of theoretical papers); I'm genuinely interested in being proven wrong.

reikonomusha 5y ago
Quantum computers do more than produce random numbers. They follow predictable statistics predicted by quantum mechanics. These computers also run programs. Maybe your definition of “quantum computer” doesn’t agree with the field at large. What’s your definition? What do you think about Google’s supremacy experiment? Do you have objections to their results? [0] This is one of many papers by Google, IBM, Rigetti, and many other quantum computer manufacturers. [0] https://www.nature.com/articles/s41586-019-1666-5 https://www.nature.com/articles/s41586-019-1666-5
- deleted 5y ago
  [deleted]
- gigel82 5y ago
  Just to be pedantic, that experiment literally generates certifiable random numbers; it is also unclear if they have a real physical device; it appears their "Sycamore" design is theoretical and actually simulated on the Jülich (classic) supercomputer.
  - reikonomusha 5y ago
    When I said they do more than “produce random numbers”, I meant that they do more than such than that which is out of their control (i.e., due to noise). By the physics of a quantum computer, at their very foundation, they’re random number generators. What you program on a quantum computer is, more or less, the shape of the distribution from which they sample. A linear congruential generator from Knuth programmed on a classical computer produces controlled pseudorandom numbers. So what? Whether a LCG or a program to produce controlled samples from a goofy Porter-Thomas distribution, they’re both coming from machines that were programmed to do a job. If the machine was neither a computer nor programmable, then the job could not be done. You haven’t refuted the point of the published existence of a computer. The paper includes both the results of a program running on a quantum computer, and a comparison of the results as simulated by a classical computer, the latter taking several orders of magnitude to complete at several orders of magnitude increased cost.
    - smoldesu 5y ago
      This is a pretty weak argument. The default state of matter is entropy: if "quantum supremacy" entails being less predictable than a traditional computer, of course it will win. But it's also competing with a vast amount of pseudorandom values that can be polled at will to create a more plausible, usable random number. If this is actually the current state of QC then consider me a little scared.
      - reikonomusha 5y ago
        It’s not competing on being less predictable. It’s competing on performing a calculation better or more accurately via a program written for the quantum computer (as opposed to a specialized machine for that singular task). The quantum computer was able to do that. The randomness is a total red herring and doesn’t contribute to the discussion as to whether a programmable computer performed a computation or not. It did, and it was verified as such. Google’s experiment isn’t “the state of quantum computing”. It’s a single scientific experiment among thousands. The particular experiment was for demonstrating a then hitherto unconfirmed claim about whether a quantum computer can do a computer science problem more efficiently. The theory already said it was true, but the experiment wasn’t yet demonstrated. It’s also an experiment lay people, and the HN tech crowd even, doesn’t care about. Because it’s deep and complicated science, not a sales pitch.
throw149102 5y ago
They've factored 15 into 5 by 3. It's a real computer, even if it's too small to do anything useful. https://arxiv.org/abs/quant-ph/0112176 https://arxiv.org/abs/quant-ph/0112176
- gigel82 5y ago
  Thank you for including a link to that experiment, it's pretty cool. My naive definition of a quantum computer would be a general purpose machine that can execute quantum programs on controlled inputs and produce valid outputs (expanded from the definition of a classical computer: "a programmable electronic device designed to accept data, perform prescribed mathematical and logical operations at high speed, and display the results of these operations.").
mikewave 5y ago
I'm sitting thirty feet away from one, friend. It exists. The pulse tube cooler is making a comforting squelchy sound. There is more entropy in your post.
- gigel82 5y ago
  So, what does it actually do besides squelching and producing random numbers?
  - mikewave 5y ago
    You'd be better served by looking at our introductory content. It can solve optimization problems, and while the hardware graph is still not billions of qubits, our hybrid systems enable you to solve much bigger problems while still heavily involving the QPU in the work. Formulating problems into the Ising model is still a difficult task, further into the realm of mathematics than the average HN poster usually goes, but it is indeed proving useful for real-world applications, e.g. with logistics and optimizing the order things are done in.
    - Ostrogodsky 5y ago
      I am sorry but nothing about your posts give me any re-assurance. From your username (What is next?, John-Facebook and Louis-Microsoft?, that is idea for you budding SF writers, usual surnames will be replaced by corporation names) to the the condescension you have treat outsiders in the comments. The article makes lots of very good points. QC is in a hype stage, it does not mean that there is no valid research or actual physical machines doing "computing" with a "small" number of bits, it means that the distance between what it is promised now explicitly or implicitly and what it can be achieved realistically from now to the next 20 years is so huge that it can easily be considered a lie. Current QCs are only good for one thing and one thing only: "Simulating" quantum systems. But in that same sense, a wind-tunnel is a fantastic "fluid-dynamics" computer providing a "realistic simulation" of how wind flows through a wing. Nobody is solving any actual optimization problems with a QC in any meaningful sense and even less there is even 1 single problem in OR that can be actually solved now only by using a QC. BTW the company you work for has a long history of making grandiose claims which are later totally refuted forcing you to backtrack, as anyone who has read Scott Aaronson's blog knows.

reikonomusha 5y ago

Quantum computers do more than produce random numbers. They follow predictable statistics predicted by quantum mechanics. These computers also run programs. Maybe your definition of “quantum computer” doesn’t agree with the field at large. What’s your definition? What do you think about Google’s supremacy experiment? Do you have objections to their results? [0] This is one of many papers by Google, IBM, Rigetti, and many other quantum computer manufacturers. [0] https://www.nature.com/articles/s41586-019-1666-5 https://www.nature.com/articles/s41586-019-1666-5

deleted 5y ago
[deleted]
gigel82 5y ago
Just to be pedantic, that experiment literally generates certifiable random numbers; it is also unclear if they have a real physical device; it appears their "Sycamore" design is theoretical and actually simulated on the Jülich (classic) supercomputer.
- reikonomusha 5y ago
  When I said they do more than “produce random numbers”, I meant that they do more than such than that which is out of their control (i.e., due to noise). By the physics of a quantum computer, at their very foundation, they’re random number generators. What you program on a quantum computer is, more or less, the shape of the distribution from which they sample. A linear congruential generator from Knuth programmed on a classical computer produces controlled pseudorandom numbers. So what? Whether a LCG or a program to produce controlled samples from a goofy Porter-Thomas distribution, they’re both coming from machines that were programmed to do a job. If the machine was neither a computer nor programmable, then the job could not be done. You haven’t refuted the point of the published existence of a computer. The paper includes both the results of a program running on a quantum computer, and a comparison of the results as simulated by a classical computer, the latter taking several orders of magnitude to complete at several orders of magnitude increased cost.
  - smoldesu 5y ago
    This is a pretty weak argument. The default state of matter is entropy: if "quantum supremacy" entails being less predictable than a traditional computer, of course it will win. But it's also competing with a vast amount of pseudorandom values that can be polled at will to create a more plausible, usable random number. If this is actually the current state of QC then consider me a little scared.
    - reikonomusha 5y ago
      It’s not competing on being less predictable. It’s competing on performing a calculation better or more accurately via a program written for the quantum computer (as opposed to a specialized machine for that singular task). The quantum computer was able to do that. The randomness is a total red herring and doesn’t contribute to the discussion as to whether a programmable computer performed a computation or not. It did, and it was verified as such. Google’s experiment isn’t “the state of quantum computing”. It’s a single scientific experiment among thousands. The particular experiment was for demonstrating a then hitherto unconfirmed claim about whether a quantum computer can do a computer science problem more efficiently. The theory already said it was true, but the experiment wasn’t yet demonstrated. It’s also an experiment lay people, and the HN tech crowd even, doesn’t care about. Because it’s deep and complicated science, not a sales pitch.

throw149102 5y ago

They've factored 15 into 5 by 3. It's a real computer, even if it's too small to do anything useful. https://arxiv.org/abs/quant-ph/0112176 https://arxiv.org/abs/quant-ph/0112176

gigel82 5y ago
Thank you for including a link to that experiment, it's pretty cool. My naive definition of a quantum computer would be a general purpose machine that can execute quantum programs on controlled inputs and produce valid outputs (expanded from the definition of a classical computer: "a programmable electronic device designed to accept data, perform prescribed mathematical and logical operations at high speed, and display the results of these operations.").

mikewave 5y ago

I'm sitting thirty feet away from one, friend. It exists. The pulse tube cooler is making a comforting squelchy sound. There is more entropy in your post.

gigel82 5y ago
So, what does it actually do besides squelching and producing random numbers?
- mikewave 5y ago
  You'd be better served by looking at our introductory content. It can solve optimization problems, and while the hardware graph is still not billions of qubits, our hybrid systems enable you to solve much bigger problems while still heavily involving the QPU in the work. Formulating problems into the Ising model is still a difficult task, further into the realm of mathematics than the average HN poster usually goes, but it is indeed proving useful for real-world applications, e.g. with logistics and optimizing the order things are done in.
  - Ostrogodsky 5y ago
    I am sorry but nothing about your posts give me any re-assurance. From your username (What is next?, John-Facebook and Louis-Microsoft?, that is idea for you budding SF writers, usual surnames will be replaced by corporation names) to the the condescension you have treat outsiders in the comments. The article makes lots of very good points. QC is in a hype stage, it does not mean that there is no valid research or actual physical machines doing "computing" with a "small" number of bits, it means that the distance between what it is promised now explicitly or implicitly and what it can be achieved realistically from now to the next 20 years is so huge that it can easily be considered a lie. Current QCs are only good for one thing and one thing only: "Simulating" quantum systems. But in that same sense, a wind-tunnel is a fantastic "fluid-dynamics" computer providing a "realistic simulation" of how wind flows through a wing. Nobody is solving any actual optimization problems with a QC in any meaningful sense and even less there is even 1 single problem in OR that can be actually solved now only by using a QC. BTW the company you work for has a long history of making grandiose claims which are later totally refuted forcing you to backtrack, as anyone who has read Scott Aaronson's blog knows.