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.
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.
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...
wut? different QEC produce differently sized logical qubits and there are absolutely machines with enough physical qubits to amount to a logical qubit:
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.
> 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.
> 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.
this is misleading. we use quantum to explain transistors, but classical computers don't exploit any quantum phenomenon such as coherence, tunnelling, or entanglement.
Is there some fair comparison of D-Wave annealer vs classical methods on optimization problems? I remember seeing papers where it was compared to some naive methods or the runtime of D-Wave approximation algorithm was compared to the runtime of classical exact algorithm -- obviously apples vs oranges.
