Google and IBM fight for quantum supremacy but theyre both wrong about it

Instead of storing information in bits as 0s or 1s like classical computers do, quantum computers use the principles of quantum physics to store information in qubits that can also be in states of 0 and 1 at the same time.

Quantum supremacy is an intermediate milestone, something to aim for long before it is possible to build large, general-purpose quantum computers.

In its quantum supremacy experiment, the Google team performed one of these difficult but useless calculations, sampling the output of randomly chosen quantum circuits. They also carried out computations on the worlds most powerful classical supercomputer, Summit, and estimated it would take 10,000 years to fully simulate this quantum computation.

Random circuit sampling has no known practical use, but there are very good mathematical and empirical reasons to believe it is very hard to replicate on classical computers. More precisely, for every additional qubit the quantum computer uses to perform the calculation, a classical computer would need to double its computation time to do the same.

They used this to show how it might be possible to squeeze a simulation of the Google experiment onto the Summit supercomputer, by exploiting the vast memory resources of that machine.

Not in one dramatic and revolutionary breakthrough, but in a whole series of small breakthroughs, with the academic community carefully scrutinizing, criticizing, and refining each step along the way.