Business Standard

The quantum supremacy

The new result will accelerate investment in research

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Alarge team of researcher­s drawn from from Google, Nasa’s Ames Research Centre, the University of California, The Oak Ridge National Laboratory in the US and the Forschungs­zentrum Research Centre in Germany claims to have achieved “quantum supremacy.” According to the paper published in Nature, the team conceptual­ised and completed a computatio­nal task, which the most powerful convention­al supercompu­ter (the Ibm-designed Summit at Oak Ridge) would take about 10,000 years to solve. This took 200 seconds on Google’s Sycamore quantum chip. The results, generated by Sycamore, were being tested simultaneo­usly by Summit, which was tackling the same problems until the complexity became too much for Summit.

This claim is being disputed by IBM, which says that the programmer­s did not program Summit efficientl­y. IBM has released a paper estimating that Summit could solve this within about 60 hours. However, as even IBM’S rebuttal concedes, there is a vast difference between 200 seconds and 60 hours.

The problem itself was esoteric, consisting of the generation of random numbers, and testing to see if these are random. The team used the architectu­re of the 54Qubit Sycamore to generate those random sequences, translated into random binary numbers. The solution has no apparent practical applicatio­n beyond being complex enough to benchmark versus the fastest convention­al super-computer.

This is the first demonstrat­ion that quantum machines can indeed perform tasks beyond the capacity of convention­al machines. It is understand­able that it has led to hyperbolic comparison­s with the first powered flight. After all, the Wright brothers’ Flyer stayed aloft only for 12 seconds on December 17, 1903, at Kittyhawk, North Carolina. The premise backing research in quantum computers is simple. A convention­al bit is binary. It can be set to one, or zero, depending on whether there is a current flowing through or not. A quantum bit uses the phenomenon of superposit­ion to be in both states, zero and one, at the same time. When you create a quantum machine with many qubits, it has the ability, in theory, to process exponentia­lly greater informatio­n. Moreover, using entangleme­nt, a property so strange that Einstein called it

“spooky”, a qubit influences the state of another qubit at a distance. That has other applicatio­ns, including communicat­ion and cryptograp­hy.

The engineerin­g and mathematic­al challenges in handling Q -chips are formidable. Q -chips have to be cooled to near absolute zero and kept in that state to function. They generate huge errors, which have to be catered for, and eliminated, to generate meaningful results, when the superposit­ions are collapsed. This means entirely new algorithms and error-correction codes must be written to handle quantum computing. The research team admits that this is a narrow result and Google is nowhere near solving these major problems yet.

But these are known unknowns. This result indicates that there are no unknown barriers to prevent quantum computing from scaling beyond convention­al machines. That gives cause for optimism that quantum computers will be capable of tackling real-world problems, which convention­al machines cannot.

Some obvious applicatio­ns would include biological problems of genetic mapping, drug developmen­t, and protein folding. Google also cites the possibilit­y that Qmachines could be used to design better batteries, or more efficient processes for manufactur­ing fertiliser (which contribute­s about 2 per cent of global carbon emission). The utility would also include cryptograp­hy. Quantum machines could conceivabl­y break all current high-end encryption very quickly. They could also generate unbreakabl­e codes that make it impossible to intercept, or tamper with messages, or to read a message without the key. This result is bound to lead to an accelerati­on of investment into research. Google has shared its data set and promised to offer time to independen­t programmer­s who can think up creative applicatio­ns. It might take years but this could be the dawn of a new era.

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