Google claims to have just achieved Quantum Supremacy, where a quantum computer is able to perform a calculation that is practically impossible for a classical one. In a line, it means that researchers at Google had solved a really difficult problem in seconds with the help or quantum computers which is supercomputer could not.

The research paper is yet to be formally vetted by peers in the field and became public after having appeared briefly on the NASA website- apparently, some of its researchers were involved in the project. It is likely to reappear soon in a complete form.



Why quantum computers are so much faster than classic ones?

In a classical computer, bits that carry information represent either a 1 or a 0; but quantum bits or qubits- which take the form of subatomic particles such as photon and electrons – can be in kind of combination of 1 and 0 at the same time, a state known as “superposition.”

Unlike bits, qubits can also influence one another through a phenomenon known as “entanglement,” which baffled even Einstein, who called it “spooky action at a distance.”

Crucially, quantum machines can crunch through large amounts of data in parallel, which helps them outpace classical machines that process data sequentially. That’s the theory. In practice, researchers have been laboring for years to prove conclusively that quantum computer can do something even the most capable conventional one can’t.

Google’s efforts have been led by John Martins, who has done pioneering work in the use of superconducting circuits to generate qubits.

Is this a real achievement?

It might sound impressive, expert says that this does not imply that the quantum computer can solve every challenging problem thrown at it.



The number-generating task was the equivalent of having a Ferrari and a truck compete in a race and, on the car’s predictable victory, declare that the Ferrari could do everything that a truck did.

While IBM and few other private establishments also have quantum computer prototypes, a common ailment is that they have their own unique propensity to errors and are not as amenable to executing real world problems as super computers.

Then again, nothing yet rules out the creation of new mathematical methods or techniques that would allow classical computers to execute the same task faster.



Some experts even question the term ‘quantum supremacy’ coined by theoretical physicist John Preskill of the California Institute of Technology, United States.

However, the Google feat shows that quantum computers are capable of a real world task. It gives confidence to private entrepreneurs are capable of real world task.



It gives confidence to private entrepreneurs and even academics to invest time and money to improving them and customize them to real world problems.





In terms of the number of qubits, the D-Wave system says it is ready to commercially launch a 5000-qubits system by 2020. It already has a 1000-qubit system at NASA. D-Wave claims that car maker Volkswagen used it quantum computers to figure out how best to control a fleet of taxis in Beijing relying on data from 10,000 cars.

But the research paper describing this experiment does not quite explain how to propose a solution is better than algorithms that are currently used t optimise traffic flow.





Is it practically useful?

For now, though, the Google team appears to have achieved Quantum Supremacy for the first time: by solving this one particular (and probably not practically useful) mathematical problem.



They performed this computational task with a quantum computer in a much faster time than even the biggest, most powerful (classical) supercomputer in the country could. But achieving useful Quantum Supremacy would enable us to:

- Make high-performance quantum chemistry and quantum physics calculations,

- Replace all classical computers with superior quantum computers,

- And to run short’s algorithm for arbitrarily large numbers.













Conclusion

Quantum Supremacy may have arrived; useful Quantum Supremacy is still far off being achieved. For example, if you wanted to factor a 20-digit semi prime number, Google’s Quantum computer cannot solve this problem at all. Your off- the shelf laptop, however, can do this in milliseconds.

Progress in the world of quantum computing is astounding, and despite the claims of its detractors, system with greater numbers of qubits are undoubtedly on the horizon. When successful quantum error-correction arrives (Which will certainly require many more qubits and the necessity of addressing and solving a number of other issues), we’ll be able to extend the coherence timescale and perform even more in-depth calculations.

With the creation of the very first programmable quantum computer that can efficiently perform a calculation on qubits that cannot be efficiently carried out on a classical computer, Quantum Supremacy has officially arrived.



Later this year, the Google team will surely publish this result and be lauded for their extraordinary accomplishment. But our biggest dreams of quantum computing are still a long way off. It's more important than ever, if we want to get there, to keep on pushing the frontiers as fast and as far as possible.



