Google claims it has reached a key milestone, using a quantum computer couldn’t manage, achieving what they call ‘quantum supremacy’. This would be the first time that a quantum computer has definitely beaten the best conventional computer - that’s also the very definition of ‘quantum supremacy’ according to Wikipedia. This is something that physicists have been trying to do for years.
Although not everyone is convinced that a normal computer would find this particular task impossible, it certainly seems that the quantum processor solves it faster. The task is a calculation that is not very useful. It was designed just to demonstrate ‘quantum supremacy’ and was made to be especially difficult for normal computers to handle. Google’s quantum computer is called Sycamore and it sports 53 qubits, or quantum bits (the quantum version of the classical binary bit physically realized with a two-state device). These behave completely different than regular bits and are very hard to manipulate. But in theory, they should allow the computer to carry out certain kinds of calculations way faster than the classical state-of-the-art machine.
The calculation in Google’s test was to figure out the probability distribution of all the possible outcomes from a quantum random number generator. You can read about the experiment in detail, from Google’s AI blog. Because the generator creates random numbers using quantum operations, simulating this distribution on a classical computer is extremely tough. But Google’s machine only needed to set itself up like the generator and then run those operations a bunch of times.
Sycamore produced an answer in just 3'20’’. But proving quantum supremacy means facing off against classical competition that has been enjoying the spotlight since the birth of the computing field. And to answer the challenge, researchers siding with conventional computers, borrowed the supercomputer Summit, that was developed by IBM for use at Oak Ridge National Laboratory. Benchmarking 200 petaflops, Summit was the fastest of its kind on a global scale, according to November 2018 benchmarks. By breaking the problem into smaller chunks and then extrapolating, they estimated that Summit would take 10,000 years to finish the same calculation. If that’s true, it means that a quantum computer can do something that is realistically impossible on a classical machine. That ladies and gentlemen, is ‘quantum supremacy’!
But not everyone agrees. IBM has released a paper as well as a blog post claiming that “an ideal simulation of the same task can be performed on a classical system in 2.5 days and with far greater fidelity”. They did that using a slightly different technique.
Scientists will now scrutinize both sides’ calculations. And even if IBM is right, it’s still significant that Sycamore is so much faster than the fastest supercomputer in the world. Specifically, 6.912 times faster. It’s the first time this kind of quantum speed-up has ever been demonstrated. It wouldn’t be the standard definition of ‘quantum supremacy’, but physicists think it’s a big deal. And it really is. This sort of achievement is a very good and accurate indicator that we’re moving down the right path to a quantum world, where unimaginable properties are unlocked and our world as we know it gets altered in ways we can’t fully comprehend yet.
That’s pretty much the deal on Google’s quantum supremacy claims and the reaction of IBM. Have a thought you’d like to share? Hit us with a comment below!