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I like to tell people that actual, programmable quantum computers do exist (which is a very important point—they’re not vaporware), but exactly like you say, in

I like to tell people that actual, programmable quantum computers do exist (which is a very important point—they’re not vaporware), but exactly like you say, in order to make them useful and scalable, more “actual science” needs to happen.

xondono 5y ago
They really don’t though. We have some things that if you squint a little, and are willing to stretch the words, look like a quantum computer.
- reikonomusha 5y ago
  They really do, and there are mountains of published experiments unambiguously verifying such.
  - Ostrogodsky 5y ago
    They "exists" in the same sense a hydraulic computer exists because I plumbed 5 valves at my house.
- anon_tor_12345 5y ago
  they do and you can get time on one (5 qubits) right now https://quantum-computing.ibm.com/composer/files/new https://quantum-computing.ibm.com/composer/files/new if you don't think these are computers then you just don't know what a computer really is https://en.wikipedia.org/wiki/Circuit_(computer_science) https://en.wikipedia.org/wiki/Circuit_(computer_science) they're not useful at all but they're still real actual unadulterated computers.
  - Hedgemaster 5y ago
    pls note a difference between a 'logical qubit' and a 'physical qubit'.. currently they don't have even 1 logical qubit, and for quantum computer to be of any use it should have >10k logical qubits...
    - anon_tor_12345 5y ago
      >currently they don't have even 1 logical qubit wut? different QEC produce differently sized logical qubits and there are absolutely machines with enough physical qubits to amount to a logical qubit: https://www.ncbi.nlm.nih.gov/books/NBK538709/#:~:text=In%20Shor's%20QEC%20code%2C%20the,errors%20on%20the%20data%20qubit https://www.ncbi.nlm.nih.gov/books/NBK538709/#:~:text=In%20S.... and realized QEC is definitely not far off https://www.nature.com/articles/ncomms7979 https://www.nature.com/articles/ncomms7979 >for quantum computer to be of any use it should have >10k logical qubits i'm aware and yet it's false to claim that these things don't compute. for the time being they're noisy computers but they're still computers.
  - xondono 5y ago
    By this logic a 74LS138 is a “digital computer”. It’s limited because it has only 3 bits, but if you play with the input bits, the output bits change!
    - anon_tor_12345 5y ago
      you're trying to say because a decoder maps n -> 2^n that it's comparable to a QC. lol. my friend you clearly don't understand interference and entanglement. btw the circuits in quantum circuits clearly aren't just combinational since they evolve in time.
      - xondono 5y ago
        No I’m not, all I’m saying is that by OPs logic, I can claim to have a computer with only a part of it. “It’s not very useful but it can make computations” is a very low bar to pass, and very basic discrete (classical) logic can clear that without problems.
        anon_tor_12345 5y ago
        you do realize that ENIAC, i.e. the computer that arguably helped the US win ww2, only had about 15 bits right?
- mikewave 5y ago
  You can access a quantum computer - to be precise, a quantum _annealer_ right now, for free, via D-Wave Leap. It may not be gate model, but it does compute using quantum effects, and it is useful for optimization problems, materials research, and other applications. No squinting required.
  - xondono 5y ago
    Except there’s a lot of people (myself included) who don’t consider a quantum annealer to be a quantum computer. There has been also very little if any actual research in other fields powered with quantum computing. We can keep moving the goal posts and claim that we have made it, but the fact is that QC keeps overpromising and under delivering.
    - mikewave 5y ago
      > Except there’s a lot of people (myself included) who don’t consider a quantum annealer to be a quantum computer. Well, great; that's an opinion. The thing is, if a device uses the quantum-mechanical properties of the universe to do calculation, then it is a quantum computer; asserting that it isn't one is a matter of semantics and categorization, since what you're really doing is redefining the term "quantum computer" to inherently include "gate model" as part of it, which is not a foregone conclusion yet. I believe, from what I've read, that at this point current and projected gate-model quantum computers will not be competitive on optimization problems where quantum annealing will be, so there is definitely utility in continuing to pursue this research and development exercise. > There has been also very little if any actual research in other fields powered with quantum computing. Here's our latest: https://science.sciencemag.org/content/early/2021/07/14/science.abe2824?rss=1 https://science.sciencemag.org/content/early/2021/07/14/scie... As a physics playground, annealers are very compelling, and materials research will definitely benefit from these devices.
      - xondono 5y ago
        > The thing is, if a device uses the quantum-mechanical properties of the universe to do calculation, then it is a quantum computer; Except this definition includes classical computers as well. At the scales of current transistors, quantum effects are required to explain their inner workings, and they are used to perform computations.
- chobytes 5y ago
  Me and my classmates were running code on real quantum computer literally earlier today. 10 qubits is enough to simulate a pair of particles interacting already.

xondono 5y ago

They really don’t though. We have some things that if you squint a little, and are willing to stretch the words, look like a quantum computer.

reikonomusha 5y ago
They really do, and there are mountains of published experiments unambiguously verifying such.
- Ostrogodsky 5y ago
  They "exists" in the same sense a hydraulic computer exists because I plumbed 5 valves at my house.
anon_tor_12345 5y ago
they do and you can get time on one (5 qubits) right now https://quantum-computing.ibm.com/composer/files/new https://quantum-computing.ibm.com/composer/files/new if you don't think these are computers then you just don't know what a computer really is https://en.wikipedia.org/wiki/Circuit_(computer_science) https://en.wikipedia.org/wiki/Circuit_(computer_science) they're not useful at all but they're still real actual unadulterated computers.
- Hedgemaster 5y ago
  pls note a difference between a 'logical qubit' and a 'physical qubit'.. currently they don't have even 1 logical qubit, and for quantum computer to be of any use it should have >10k logical qubits...
  - anon_tor_12345 5y ago
    >currently they don't have even 1 logical qubit wut? different QEC produce differently sized logical qubits and there are absolutely machines with enough physical qubits to amount to a logical qubit: https://www.ncbi.nlm.nih.gov/books/NBK538709/#:~:text=In%20Shor's%20QEC%20code%2C%20the,errors%20on%20the%20data%20qubit https://www.ncbi.nlm.nih.gov/books/NBK538709/#:~:text=In%20S.... and realized QEC is definitely not far off https://www.nature.com/articles/ncomms7979 https://www.nature.com/articles/ncomms7979 >for quantum computer to be of any use it should have >10k logical qubits i'm aware and yet it's false to claim that these things don't compute. for the time being they're noisy computers but they're still computers.
- xondono 5y ago
  By this logic a 74LS138 is a “digital computer”. It’s limited because it has only 3 bits, but if you play with the input bits, the output bits change!
  - anon_tor_12345 5y ago
    you're trying to say because a decoder maps n -> 2^n that it's comparable to a QC. lol. my friend you clearly don't understand interference and entanglement. btw the circuits in quantum circuits clearly aren't just combinational since they evolve in time.
    - xondono 5y ago
      No I’m not, all I’m saying is that by OPs logic, I can claim to have a computer with only a part of it. “It’s not very useful but it can make computations” is a very low bar to pass, and very basic discrete (classical) logic can clear that without problems.
      - anon_tor_12345 5y ago
        you do realize that ENIAC, i.e. the computer that arguably helped the US win ww2, only had about 15 bits right?
mikewave 5y ago
You can access a quantum computer - to be precise, a quantum _annealer_ right now, for free, via D-Wave Leap. It may not be gate model, but it does compute using quantum effects, and it is useful for optimization problems, materials research, and other applications. No squinting required.
- xondono 5y ago
  Except there’s a lot of people (myself included) who don’t consider a quantum annealer to be a quantum computer. There has been also very little if any actual research in other fields powered with quantum computing. We can keep moving the goal posts and claim that we have made it, but the fact is that QC keeps overpromising and under delivering.
  - mikewave 5y ago
    > Except there’s a lot of people (myself included) who don’t consider a quantum annealer to be a quantum computer. Well, great; that's an opinion. The thing is, if a device uses the quantum-mechanical properties of the universe to do calculation, then it is a quantum computer; asserting that it isn't one is a matter of semantics and categorization, since what you're really doing is redefining the term "quantum computer" to inherently include "gate model" as part of it, which is not a foregone conclusion yet. I believe, from what I've read, that at this point current and projected gate-model quantum computers will not be competitive on optimization problems where quantum annealing will be, so there is definitely utility in continuing to pursue this research and development exercise. > There has been also very little if any actual research in other fields powered with quantum computing. Here's our latest: https://science.sciencemag.org/content/early/2021/07/14/science.abe2824?rss=1 https://science.sciencemag.org/content/early/2021/07/14/scie... As a physics playground, annealers are very compelling, and materials research will definitely benefit from these devices.
    - xondono 5y ago
      > The thing is, if a device uses the quantum-mechanical properties of the universe to do calculation, then it is a quantum computer; Except this definition includes classical computers as well. At the scales of current transistors, quantum effects are required to explain their inner workings, and they are used to perform computations.
chobytes 5y ago
Me and my classmates were running code on real quantum computer literally earlier today. 10 qubits is enough to simulate a pair of particles interacting already.