5 ms·

Last I knew (a few months ago) we were somewhere less than 20 qubits and getting a straight answer on “does it work” depended on who was being interviewed. How

by doitLP 8y ago

Last I knew (a few months ago) we were somewhere less than 20 qubits and getting a straight answer on “does it work” depended on who was being interviewed. How do they have a 2048 qubit chip? And why is it a binary multiple? Did I miss some announcement?

gaze 8y ago
At best, d-wave is making an adiabatic quantum computer, not a gate based quantum computer, at worst (most likely), they're a scam.
- core-questions 8y ago
  It doesn't look like a scam. When you sign up, you get an API key, and you can get an SDK and submit problems to it. I'm not enough of a mathematician to be able to formulate anything, but there's a growing list of people that have been able to get useful results from it.
  - samstave 8y ago
    Where can one see the results of a useful result.. and by that i mean Submitted problem X to Dwave cost $Y and returned in Z minutes. Vs Problem X cost $A and returned in W minutes from AWS...
  - Dylan16807 8y ago
    No one questions its ability to do some amount of math. The doubt is in how it scales.
  - jorgec 8y ago
    I don't know which part of "we are running a quantum computer but we don't wanna show you" (they are saying the same during 10 years), is not a scam?. They could run the api in a server and sells us as it runs in a quantum machine.
- krastanov 8y ago
  Nope, at best they have a "quantum annealing machine" which is not more powerful than a classical computer. Adiabatic quantum computers are just as powerful as the gate model of quantum computing.
hannob 8y ago
What D-Wave is building is not what most other people mean when they say Quantum Computer. What they build is as far as my lay understanding is something that is much more limited than a "normal" quantum computer. That's why you can't compare qubits from D-Wave with other QC technology. What D-Wave has is technically called an adiabatic quantum computer and they've yet to show that you can do anything useful with it.
- krastanov 8y ago
  Nitpicking: It is not an adiabatic quantum computer either. Adiabatic quantum computers have as much computing power as the other more usual models of quantum computing (the quantum circuit model for instance). Dwave have a quantum annealing machine, which as far as I know does not do anything better than a classical computer.
mtgx 8y ago
A universal quantum computer with 20 qubits is kind of like a general purpose 20-core CPU. A 2000-qubir D-WAVE quantum annealing computer is kind of like a 2000 "cores" GPU. It's not a perfect analogy by any means but it should make the difference clearer.
- p1esk 8y ago
  It doesn’t.
deepnotderp 8y ago
Those guys are all building gate based quantum computers which are universal and can run (in theory) any quantum algorithm such as Shor's algorithm. By contrast, D-Wave is pursuing "quantum annealing" which basically solves very specific types of optimization problems and the hope is that it will be economically useful enough in the near future. See this for a decent comparison: http://moss.csc.ncsu.edu/~mueller/qc/qc18/readings/gottlieb2.pdf http://moss.csc.ncsu.edu/~mueller/qc/qc18/readings/gottlieb2...
chriswarbo 8y ago
D-wave have spent a lot of effort to show that their machine is quantum, and it seems convincing enough. However, it's not a computer (i.e. a general-purpose machine, able to run arbitrary programs https://en.wikipedia.org/wiki/Universal_Turing_machine https://en.wikipedia.org/wiki/Universal_Turing_machine). Instead, their machine is a special-purpose calculator, which finds an approximate minimum value for a certain sort of problem ( https://en.wikipedia.org/wiki/Mathematical_optimization https://en.wikipedia.org/wiki/Mathematical_optimization ). I always take D-wave's claims with a pinch of salt, since their original announcements were incredibly misleading. They claimed their calculator could solve problems orders of magnitude faster than a program running on a classical computer, but they turned out the be comparing apples with oranges: their machine finds an approximate solution, while the program they compared against was guaranteed to find an exact solution (i.e. it would carry on going until all other possibilities had been eliminated). Other researchers did a more apples to apples comparison, by writing an approximate program (essentially simulating what the D-wave machine does). They found that a normal consumer laptop was actually much faster than the $10,000,000 D-wave machine. D-wave's newer machines are more powerful, but I don't know if their machines benefit from the scaling properties of quantum computers (their qubits are noisy, which AFAIK prevents them all entangling completely)

by doitLP 8y ago

gaze 8y ago

At best, d-wave is making an adiabatic quantum computer, not a gate based quantum computer, at worst (most likely), they're a scam.

core-questions 8y ago
It doesn't look like a scam. When you sign up, you get an API key, and you can get an SDK and submit problems to it. I'm not enough of a mathematician to be able to formulate anything, but there's a growing list of people that have been able to get useful results from it.
- samstave 8y ago
  Where can one see the results of a useful result.. and by that i mean Submitted problem X to Dwave cost $Y and returned in Z minutes. Vs Problem X cost $A and returned in W minutes from AWS...
- Dylan16807 8y ago
  No one questions its ability to do some amount of math. The doubt is in how it scales.
- jorgec 8y ago
  I don't know which part of "we are running a quantum computer but we don't wanna show you" (they are saying the same during 10 years), is not a scam?. They could run the api in a server and sells us as it runs in a quantum machine.
krastanov 8y ago
Nope, at best they have a "quantum annealing machine" which is not more powerful than a classical computer. Adiabatic quantum computers are just as powerful as the gate model of quantum computing.

hannob 8y ago

What D-Wave is building is not what most other people mean when they say Quantum Computer. What they build is as far as my lay understanding is something that is much more limited than a "normal" quantum computer. That's why you can't compare qubits from D-Wave with other QC technology. What D-Wave has is technically called an adiabatic quantum computer and they've yet to show that you can do anything useful with it.

krastanov 8y ago
Nitpicking: It is not an adiabatic quantum computer either. Adiabatic quantum computers have as much computing power as the other more usual models of quantum computing (the quantum circuit model for instance). Dwave have a quantum annealing machine, which as far as I know does not do anything better than a classical computer.

mtgx 8y ago

A universal quantum computer with 20 qubits is kind of like a general purpose 20-core CPU. A 2000-qubir D-WAVE quantum annealing computer is kind of like a 2000 "cores" GPU. It's not a perfect analogy by any means but it should make the difference clearer.

p1esk 8y ago
It doesn’t.

deepnotderp 8y ago

Those guys are all building gate based quantum computers which are universal and can run (in theory) any quantum algorithm such as Shor's algorithm. By contrast, D-Wave is pursuing "quantum annealing" which basically solves very specific types of optimization problems and the hope is that it will be economically useful enough in the near future. See this for a decent comparison: http://moss.csc.ncsu.edu/~mueller/qc/qc18/readings/gottlieb2.pdf http://moss.csc.ncsu.edu/~mueller/qc/qc18/readings/gottlieb2...

chriswarbo 8y ago

D-wave have spent a lot of effort to show that their machine is quantum, and it seems convincing enough. However, it's not a computer (i.e. a general-purpose machine, able to run arbitrary programs https://en.wikipedia.org/wiki/Universal_Turing_machine https://en.wikipedia.org/wiki/Universal_Turing_machine). Instead, their machine is a special-purpose calculator, which finds an approximate minimum value for a certain sort of problem ( https://en.wikipedia.org/wiki/Mathematical_optimization https://en.wikipedia.org/wiki/Mathematical_optimization ). I always take D-wave's claims with a pinch of salt, since their original announcements were incredibly misleading. They claimed their calculator could solve problems orders of magnitude faster than a program running on a classical computer, but they turned out the be comparing apples with oranges: their machine finds an approximate solution, while the program they compared against was guaranteed to find an exact solution (i.e. it would carry on going until all other possibilities had been eliminated). Other researchers did a more apples to apples comparison, by writing an approximate program (essentially simulating what the D-wave machine does). They found that a normal consumer laptop was actually much faster than the $10,000,000 D-wave machine. D-wave's newer machines are more powerful, but I don't know if their machines benefit from the scaling properties of quantum computers (their qubits are noisy, which AFAIK prevents them all entangling completely)