Microsoft last week claimed a breakthrough in quantum computing, an eagerly-awaited technology much like artificial intelligence (AI), that holds the promise of performing tasks beyond the capabilities of current technologies. The company said it had been successful in creating a new chip that would fast-track the development of a meaningful quantum computer from decades to a few years. Essentially, Microsoft has claimed to have found a novel way to create qubits (short for quantum bits), the basic unit of data that is stored and processed in a quantum computer. The company has also claimed that this novel way produces qubits that are more stable than those produced by existing methods. The claim, if it stands, could become a major milestone not just in quantum computing, but also in physics. That is because the process of creating these qubits involves working with a physical state that is long known to be theoretically possible but has never been attained. This is the reason why there has been a little scepticism around this announcement as of now. Quantum computing Quantum computers are not just the next generation of superfast computers. These are very different in the way they work, the way they handle and process information, and even in the way they look. They are designed to utilise the very special properties that tiny particles, smaller than an atom, exhibit. One such property is superposition, or the ability of a quantum particle to exist in multiple states at the same time. This property is used in a quantum computer to supercharge calculations in a way that traditional computers are incapable of doing. In traditional computers, data are stored and processed through billions of small transistors that can each handle only one bit of information (0 or 1) at a time. Quantum computers use electrons or other similar particles to process data. Superposition allows these particles, or qubits, to be in both 0 and 1 state at the same time. In fact, they can exist in every combination of 0 and 1 simultaneously. Interaction with other qubits allows for a kind of parallel processing that is not possible in a normal computer where data processing happens one step at a time, even though at lightning speeds. However, quantum computing faces big challenges. The quantum behaviour of a particle collapses into normal behaviour the moment the system is observed or measured. This is because any act of measurement, or observation, is not possible without disturbing these extremely tiny systems. Any other external disturbance, such as deviations in temperature or pressure, also collapses the system. Maintaining the stability of qubits is a huge issue. The other challenge pertains to the integrity of the outcome. The multiple states of a qubit lead to multiple outcomes, only one of which is desirable. Getting the quantum computer to throw this correct outcome, instead of millions of other possibilities, is also a challenge. Disturbances caused in any qubit can result in errors in calculations, and algorithms need to correct for these, which, in turn, require many more qubits. The more stable the qubits are, the fewer the errors. What Microsoft has done There are several ways in which quantum computers are being designed. One of the major differences is how qubits are created and controlled. Microsoft has said the qubits created through its novel process are more resilient, and make significant advances over alternative platforms in terms of scalability, error generation and error correction. It has also said this opens up the pathway for creating a million-qubit system within a few years. Quantum computers using other methods have barely managed to reach 1,000-qubit systems. For quantum computers to become meaningful, and start working on real-world problems, they need to control and operate a million or ten million qubit systems. Speaking to The Indian Express, Arindam Ghosh, professor at the Indian Institute of Science, Bengaluru, said, “One million physical qubits would roughly scale down to about a few thousand (error-corrected) logical qubits in the existing systems because of the need for error correction. If what Microsoft is claiming is correct, and the quality of qubits is indeed superior, then the errors are expected to be smaller, and this ratio of physical to logical cubits would be much higher. This would significantly move the needle in the development of quantum computers.” He said the scepticism around the announcement was also understandable. “What Microsoft is claiming to have achieved is very big and significant. It is also very difficult. Scientists have been trying to create this new physical state for a long time but have not succeeded. Any big breakthrough does invite greater scrutiny, and that is what seems to be happening. There is nothing surprising about this,” he said.
