Has Google reached quantum supremacy? IBM claim otherwise

Attempting to explain the science of how the universe works at sub-atomic scales has always been a hotly contended issue in physics. The realm of quantum mechanics has often divided scientific opinion, Richard Feynman once said that “I think I can safely say that nobody understands quantum mechanics” – and he was a Nobel laureate and theoretical physicist. This can make it seem like the quantum realm is lost to us in a haze of mystery, but there are scientists who are studying how this weirdness can be harnessed for humanity’s benefit.

Classical computers function on the basis of bits, essentially a unit of information representing either an on or off state, otherwise known as 1 (on) or 0 (off). Computers represent this information via transistors, small devices that can be used to block or allow the flow of electrons and can, therefore, be switched on or off, representing the 1 or 0 state. The more of these transistors you can fit on a computer chip, the faster a computer can carry out calculations.

Richard Feynman once said that, “I think I can safely say that nobody understands quantum mechanics” – and he was a Nobel laureate and theoretical physicist

However, we are fast approaching the physical limit for how small we can make transistors. This size limit is where quantum computing comes in, quantum computers can instead use qubits as the basis for their information processing. Like bits, qubits can also be in an on or off state, but fortunately (or unfortunately for your brain) this is where that quantum weirdness creeps in. Unlike bits, where only 1 or 0 is an option, qubits can exist in a state in between these two absolutes – a phenomenon known as superposition. This property allows the qubits to exist in multiple states at once, a fact that can be exploited by any potential quantum computer to run multiple calculations in parallel, potentially allowing for calculations orders of magnitude faster than a classical computer.

This faster-processing speed would have far-reaching consequences in many areas. For example, in pharmacology, drug discovery is driven by using computers to check huge molecular libraries and finding possible matches for key biological molecules in the body. Quantum computing could allow for huge advancement in the speed at which this process could occur and possibly accelerate the rate of novel drug discovery.

Quantum computing could allow for huge advancement in the speed at which this process could occur and possibly accelerate the rate of novel drug discovery

“Quantum supremacy”, a term coined by John Preskill in 2012, is the point at which a quantum computer could quickly complete a computation that would take a classical computer an impossibly long time to finish. Google claims that they have reached this point with their quantum processor named Sycamore. The processor was given the comparatively mundane task of determining the randomness of a sequence of numbers, a task which took 3 minutes and 20 seconds to complete. In comparison, they claim that the world’s most powerful classical supercomputer, Summit, would take 10,000 years to finish the same task, definitely not a reasonable amount of time to wait.

So that’s it, right? Have we reached the quantum era and the reign of classical computers is at an end? Google’s rivals IBM don’t think so, they have said, “by its strictest definition the goal has not been met. But more fundamentally, because quantum computers will never reign “supreme” over classical computers”. They argue that Summit could solve the problem in 2.5 days if programmed correctly, a time frame far more reasonable than the 10,000 years proposed by Google and that to talk about quantum computers replacing classical computers is not reasonable anyway, as they will “work in concert” with one another, each having their own strengths.

Summit could solve the problem in 2.5 days if programmed correctly

Perhaps the quantum era is dawning, but if the tech giants are to be believed there is a lot of work to be done before we’ll be using the power of superposition for anything other than confusing people. The potential of this untapped knowledge is seemingly on the forefront of many computer scientists’ and physicists’ minds and future developments are likely to be something to watch out for in the years to come.