Quantum computing reminds me of time travel for all the same reasons. This is not a quick win.
How would you even validate you built a quantum computer?
IBM Q system in development with working 50 qubit processor
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Re: IBM Q system in development with working 50 qubit processor
#52The article appears to be saying that they are offering an actual quantum computer as a service, but as I recall, their previous offering was a simulation of a quantum computing environment. Yet, this same article refers to that thing as if it were a real QC. This makes me skeptical that the thing being offered here is a real quantum computer...Anyone here have any insight into whether this is legitimate?
The last news from IBM on HN about their quantum offering was that they had optimised the memory required for simulating quantum computers. 50-qubits seemed to the the upper limit before, but they managed to simulate a 56-qubit circuit. It was a good read: https://arxiv.org/abs/1710.05867 They've had real hardware for a while, though, and they have 5-qubit and 16-qubit machines that anyone can try via IBM Q experienc…
There is no such thing as a quantum computer in 2017. It is fantasy.
Re: IBM Q system in development with working 50 qubit processor
#53I've been following quantum computing since D-Wave made its press release some years back. Now I'm a complete skeptic. The huge red flag I can't get over is if it is as so, why can no one validate it after all this time? Why is there the proverbial "it works but not in the way you think it works" (i.e., quantum annealing) or "it works but we can use non-QM systems to simulate it faster, better, cheaper by a factor of…
Because you have to build the quantum computer in a world that is overwhelmingly classical.
There are no qualifiers along the lines of "underlying phenomena". It's simply difficult to get a stable enough interface between the classical and the quantum, so you can control it, while at the same time isolating it enough that it doesn't decohere to classicality.
Who knows, maybe reliable scalable quantum computation truly isn't feasible for some reason, but if you study the physics, the fact that this is so hard is not really a surprise.
Re: IBM Q system in development with working 50 qubit processor
#54Earlier quoted context omitted.
Wait, I didn't think we had actual quantum computers yet. https://en.wikipedia.org/wiki/Quantum_computing
From your link: "A small 16-qubit quantum computer exists and is available for hobbyists to experiment with via the IBM quantum experience project."
From the link in that sentence: "The IBM Quantum Experience (QX) enables anyone to ... ... explore tutorials and simulations around what might be possible with quantum computing."
Re: IBM Q system in development with working 50 qubit processor
#55Earlier quoted context omitted.
Their previous offerings have been 2 physical quantum computers that can be accessed over the cloud. One with 5 qubits, and another with 16 qubits[0]. These computers have had thousands of users who have run millions of quantum algorithms [1]. [0]: https://www-03.ibm.com/press/us/en/pressrelease/52403.wss [1]: https://www.engadget.com/2017/11/10/ibm-50-qubit-quantum-com...
Wait, I didn't think we had actual quantum computers yet. https://en.wikipedia.org/wiki/Quantum_computing
We've had quantum computers since the 90's. We just haven't had "useful" quantum computers yet [0].
An implementation of quantum computers that is currently flourishing is one that is built out of superconducting circuits. This makes it easier to scale the quantum computer because you can leverage existing nanoelectronic fabrication techniques [1].
[0]: https://en.wikipedia.org/wiki/Timeline_of_quantum_computing
[1]: https://en.wikipedia.org/wiki/Superconducting_quantum_comput...
Re: IBM Q system in development with working 50 qubit processor
#56What are they doing about error correction? Not that it makes this any less impressive (everything starts somewhere ), are they simply ignoring the problem?
I just saw a talk by I forgot which bell labs engineer was on the transistor team. He told it took two or more years to get the errors to a useful level. It's easy to think transistor are magic solid devices, they were not.
But as they are analog devices, there are no errors with transistors
There are manufacturing defects, there are inefficient designs, inefficient production methods, poor circuit designs (like using them in common base - not wrong depending on the situation - instead of common emitter)
Re: IBM Q system in development with working 50 qubit processor
#57Earlier quoted context omitted.
Wait, I didn't think we had actual quantum computers yet. https://en.wikipedia.org/wiki/Quantum_computing
We've had quantum computers since the 90's. We just haven't had "useful" quantum computers yet [0]. An implementation of quantum computers that is currently flourishing is one that is built out of superconducting circuits. This makes it easier to scale the quantum computer because you can leverage existing nanoelectronic fabrication techniques [1]. [0]: https://en.wikipedia.org/wiki/Timeline_of_quantum_computing [1]:…
> "We've had quantum computers since the 90's".
It wasn't until 2005 we had the first (probable) qubyte created at the University of Innsbruck in Austria.
Re: IBM Q system in development with working 50 qubit processor
#58Re: IBM Q system in development with working 50 qubit processor
#59Presenting the pictures of a quantum computer with adbobe flash is an impressive combination of technologies. I hope they are use a different technology stack to develop the OS of that machine ;-)
Re: IBM Q system in development with working 50 qubit processor
#60Quantum computing reminds me of time travel for all the same reasons. This is not a quick win. How would you even validate you built a quantum computer?
Quantum computers can be simulated classically, in a timeframe exponentially related to the number of qubits. So as long as the quantum computer is not too big you can compare the results to an exact classical simulation and see if it works. The current record for classical simulation is 56 qubits (https://arxiv.org/abs/1710.05867). This is an active area of research, since we want to be able to check the early-generation quantum computers carefully.