Quantum science and the National Quantum Mission

Quantum science studies matter and energy at the scale of atoms and subatomic particles, where the usual rules of everyday physics give way to stranger ones. A quantum bit, or qubit, can exist in a combination of states, and entangled particles can show correlations that classical physics cannot explain. These properties suggest new kinds of computers, sensors and communication systems, but building them requires keeping fragile quantum states intact against heat, vibration and electrical noise, which is why progress has been slow and hard-won.

The National Quantum Mission was approved by the Union Cabinet on 19 April 2023, with a total outlay of 6,003.65 crore rupees for 2023-24 to 2030-31, implemented by the Department of Science and Technology. Its stated aim is to seed, nurture and scale up scientific and industrial research in quantum technology. The mission targets intermediate-scale quantum computers with 50 to 1,000 physical qubits within eight years, across platforms such as superconducting and photonic systems, and it is organised around four themes: quantum computing, quantum communication, quantum sensing and metrology, and quantum materials and devices.

Quantum communication is the most concrete near-term application. Quantum key distribution uses quantum properties to detect eavesdropping on a communication channel, offering a way to share encryption keys with security grounded in physics rather than in the difficulty of a mathematical problem. That matters because a future quantum computer could break some widely used encryption, so governments and banks are interested in communication that remains secure even then. Satellite-based and ground-based quantum communication links are both under development in several countries.

Sensing is the quieter application. Quantum sensors can measure gravity, magnetic fields and time with exceptional precision, with uses in navigation without satellites, mineral exploration, medical imaging and fundamental science. Unlike quantum computing, which must beat classical computers at a useful task to justify its cost, quantum sensing only has to be better at one measurement to be valuable.

The policy lesson is about time horizons. Quantum technology will not transform the economy in a single budget cycle, and its benefits may arrive first in secure communication and sensing rather than in general-purpose computing. Funding should therefore be judged on trained people, working devices and standards built over years, not on headlines about qubit counts alone.