According to a report from Financial Times last week, Google scientists and their partners at NASA's Ames Research Center claimed that their team had achieved quantum supremacy in a briefly-present online publication.
Described in the now-offline paper, their 53-qubit quantum computer named Sycamore is capable of solving an ultra-complicated calculation in a matter of 3 minutes and 20 seconds, which could take up to 10,000 years for the currently most advanced supercomputers to solve.
Quantum computing is an advanced technology that takes advantage of superposition, a quantum mechanical phenomenon. The basic unit of its information structure is a qubit.
Qubits are analogous to bits in a classical computer. Just like bits, qubits can store informaion as either 1s or 0s. But on top of that, qubits have another trick up their sleeves: they can also be both the 1 and 0 states at the same time, thanks to their quantum physical nature.
For example, two qubits would have enough combinations to embody four possible states, whereas three qubits would amount to eight. Evidently, the amount of information a quantum computing device increases in an exponential relation with the number of qubits it possessed.
In the recent years, the quantum computing field has witnessed a significant increase in funds and attention from governments as well as private firms. To have their device completing an astronomical amount of calculations in a split second is deemed as the claim of quantum supremacy.
The claim by Google, however, was met with some high-profile criticism soon after the report came out. Many contended that the Google quantum processor isn't as "supreme" as it seems in the paper, because it can only beat the supercomputer at an extremely specific task.
Dario Gil, a senior researcher with IBM—Google's direct competitor in quantum computing—criticized the claim as Google's publicity stunt. In his opinion, a quantum computing device, which is only able to execute one single function without real-world implication, prove nothing about the universality and usefulness of this device.
What's more, it is a well-known fact that all current quantum computers are quite noisy and require error correction on a frequent basis. Some researchers believe that the existing physical components of these computers are inherently noisy, and it would take a long while until fault-tolerant quantum computing finally appear. In Google's claim of "quantum supremacy", the noisiness of their machine isn't well addressed either.
Indeed, Sycamore's achievement is an undeniable victory of Google and a milestone. But to many, the true "supremacy" is still miles (if not hundreds of or thousands of miles) away.
Do you want to find out how quantum computers work? Watch this video from Nature Video.
Quantum supremacy: A three minute guide
Source: the Verge