Google officially announced that it has achieved quantum supremacy, almost one month after the initial leak on a NASA portal. In a paper published in the scientific journal Nature, Google says that it’s 54-qubit Sycamore processor was able to perform a calculation in 200 seconds that would take the world’s most powerful supercomputer 10,000 years to complete. But IBM does not agree.
According to the paper, quantum processors based on superconducting qubits will be able to perform computations in Hilbert space on dimension 2^53, which is approximately 9*10^15. It’s beyond the reach of the fastest classical supercomputers available. This experiment shows the first computation that can only be performed by a quantum processor. We expect the computational power will continue to grow at the double exponential rate.
There has been a string of debates surrounding this achievement by Google about Quantum Supremacy, led by IBM. Google has claimed to have beaten IBM supercomputer in performing the random number task. Google claims that the quantum processor can perform the task in just 20 seconds that takes 10,000 years for the IBM supercomputer. In a blog post, IBM argued that “an ideal simulation of the same task can be performed on a classical system in 2.5 days and with far greater fidelity.”
Another problem researchers pointed out is that quantum supremacy is achieved in just a single domain like random number generation rather than in other fields such as cryptography. Currently, quantum processors are still not practically available to check the claims, so it would be interesting to see how these processors will perform in terms of complicated problems.
Both Google and IBM are taking different approaches to represent quantum value and quantum supremacy. A practical definition of quantum value says that quantum computers offer better benefits over the classical computer for solving practical problems. IBM is stating that quantum value is much more imperative, while Google is pushing the term quantum supremacy. However, what makes quantum value a more confusing is that it’s subjective. Currently, there is no method to prove quantum value scientifically.
Supremacy and quantum value haven’t demonstrated any practical value yet, and IBM has claimed that it might take 10 years or so for these technologies to do so. It looks like the debate on supremacy is only going to get juicier in years to come.