Context

• Last week, India decided to join the global efforts of research on Quantum Computers by setting up a 6000 crore National Mission on Quantum Technologies and Applications.
• Developing homegrown quantum computers is one of the major objectives of the mission.

Background to the Genesis of the Idea of Quantum Computers

• Richard Feynman, a Nobel Prize-winning physicist, at a lecture (in 1982) at the MIT Computer Science and Artificial Intelligence Laboratory proposed the development of different, more powerful computers by utilising the quantum mechanical properties of matter.
• This lecture is often considered the original idea behind quantum computers.

The concept of Quantum Computers

• Quantum computers are not just the next generation of faster and more efficient computers, they exploit the very special properties of matter in the sub-atomic world for calculations beyond the capabilities of ordinary computers.
• This technology uses the concepts of Superposition, Entanglement to solve calculations and complex problems in a matter of seconds.
• Superposition
  • Small particles, the size of atoms or its constituents like protons or electrons exhibit strange properties that are against our everyday experiences.
  • These particles can exist at multiple locations at the same time and this phenomenon is called superposition.
• Entanglement: The ability of a particle to instantaneously influence the behaviour of another with whom it had an earlier ‘interaction’, even when they are separated by arbitrarily great distances.

How quantum computers are different from conventional computers?

• Conventional computers store and process information in bits (0 and 1).
  • A two-bit system in a conventional computer can have four states; (0,0), (0,1), (1,0), and (1,1), but only one at a time.
  • To go through each of these four states, the computer has to take four steps.
• Whereas Quantum computers use quantum bits or qubits. The concept of superposition allows a supercomputer to process the ones and zeroes simultaneously.
  • Therefore, a quantum computer can process a lot more information than conventional computers.
  • With just a few qubits quantum computers can outpace traditional computers.
• Quantum computers are fundamentally different in the way they handle and process information.
  • They are meant to be useful in some very specific situations where the traditional ways of computing are inadequate.
• As more qubits are added, the processing capability of the quantum computer increases exponentially.
• Tasks that conventional computers would take millions of years to finish can become a matter of seconds with a quantum computer
• Such tasks are found in a variety of domains: Internet and data security, Health research, Artificial intelligence and Machine Learning, etc.

Challenges in Building a Quantum Computer

• Requirements of very cold temperatures and extreme isolation without which there's a significant risk of errors.
• Error correction, and the ability to guide the computer to produce the correct result as the most favoured option, is one of the ongoing areas of active research.
  • The parallel processing happening in superposition states all lead to different results, only one of which is correct or desirable.
  • The final outcome is randomly selected from the range of possibilities which would make quantum computer totally useless.

The Mission in India

• Work on quantum technologies has been going on in India for the past 10 years, more vigorously in the last four-five years.
• One objective of the mission is to build a 1,000-qubit computer in the next eight years.
• A collaborative effort of Tata Institute of Fundamental Research (TIFR), Defence Research and Development Organisation (DRDO), and Tata Consultancy Services (TCS) is developing a 7-qubit quantum computer.
• Much more powerful quantum computers, having a few hundred qubits, have been developed in some other countries, though none of these have yet performed calculations beyond the capabilities of regular computers.

Conclusion

• The excitement in the scientific community about the Quantum Mission is because it allows India to join a global technology development race when it is still in the nascent stages. 
• To achieve the objective, India should partner and incentivise private sectors; many of them, are already working on developing Quantum computers.
• By implementing right policies, investing heavily on R&D, India has the potential to achieve the objective of building a 1000 qubit computer.