Quantum Technology and the National Quantum Mission

The correct answer is B, the Department of Science and Technology. The Union Cabinet approved the mission on 19 April 2023 and placed its implementation with that department, which runs it through four thematic hubs at leading academic institutions. Option A is wrong because the Department of Atomic Energy looks after nuclear power, nuclear research centres and related applications, and it is not the nodal agency here. Option C is wrong because the Department of Space, which runs the Indian Space Research Organisation, has demonstrated quantum key distribution of its own but does not implement the mission. Option D is wrong because the Ministry of Electronics and Information Technology runs programmes in semiconductors and artificial intelligence, a separate stream. Learn the pairing of each mission with its nodal department, since that is the usual question format.

The correct answer is B, 50 to 1,000 physical qubits. This is the headline target stated when the Cabinet approved the mission, and it is to be achieved on more than one hardware platform, including superconducting and photonic technology, rather than on a single design. The range is called intermediate scale because machines of this size are large enough to be useful for research but still too small to run error corrected algorithms at full strength. Option A is wrong because machines of a few dozen qubits already existed worldwide when the mission was framed, so that would be no target at all. Option C is wrong because a thousand is the upper and not the lower end of the stated range. Option D is wrong because no national programme has set a target of tens of thousands of physical qubits for eight years.

The correct answer is B, the Indian Institute of Science, Bengaluru. The mission divides the field among four thematic hubs, and quantum computing was assigned to the Indian Institute of Science. Option A is wrong because the Indian Institute of Technology Madras hosts the hub for quantum communication, which covers quantum key distribution over fibre and by satellite. Option C is wrong because the Indian Institute of Technology Bombay hosts the hub for quantum sensing and metrology, the branch that produces atomic clocks, magnetometers and gravimeters. Option D is wrong because the Indian Institute of Technology Delhi hosts the hub for quantum materials and devices, which builds the superconductors, topological materials and single photon sources the other three branches depend on. Learn the four as a set, since questions often swap two of them.

The correct answer is B, superposition. A classical bit must be either zero or one, but a qubit can occupy a combination of both states until it is measured, and this is what allows a register of n qubits to represent two raised to the power n states together. Option A is wrong because entanglement is the separate property by which two particles share a single quantum state, so that measuring one instantly fixes the outcome for the other however far apart they are. Option C is wrong because decoherence is the opposite of a useful property: it is the loss of quantum behaviour when a qubit interacts with its surroundings, and it is the main engineering obstacle. Option D is wrong because tunnelling, the passage of a particle through a barrier it classically could not cross, is a different quantum effect altogether.

The correct answer is B, factoring large integers. Peter Shor published the algorithm in 1994, and it would let a sufficiently large quantum computer break the large number factorisation on which public key encryption such as the RSA system depends. That threat is the reason governments and standards bodies have begun work on post quantum cryptography. Option A is wrong because searching an unsorted database is the task of Grover's algorithm, published by Lov Grover in 1996, which gives a quadratic rather than an exponential speedup. Option C is wrong because sorting is not a problem on which quantum computers hold any celebrated advantage. Option D is wrong because image compression is a classical signal processing task with no quantum algorithm of this importance. Keep the pair clear: Shor factors, Grover searches.

The correct answer is B, an unknown quantum state cannot be copied and measuring it disturbs it. The no cloning theorem forbids an exact copy of an unknown state, and any measurement changes the state, so an eavesdropper on the channel inevitably leaves statistical traces that the two legitimate parties detect when they compare a sample of their key. The BB84 protocol of Charles Bennett and Gilles Brassard, proposed in 1984, is built on exactly this. Option A is wrong because double encryption is a classical measure and is not what makes the method secure. Option C is wrong because the speed of the signal has nothing to do with secrecy. Option D is wrong because quantum key distribution runs over ordinary optical fibre and free space links that any receiver can physically access; the security lies in physics, not in hiding the channel.

The correct answer is B, rupees 6,003.65 crore. The Union Cabinet approved this amount on 19 April 2023 for the period 2023-24 to 2030-31, that is an eight year span, and the Department of Science and Technology implements the mission within it. Option A is wrong because a thousand crore is far below the sanctioned figure and would not cover four thematic hubs and their hardware programmes. Option C is wrong because ten thousand crore is a round number candidates often guess but is not the approved outlay. Option D is wrong because twenty five thousand crore is of the order of much larger industrial programmes rather than this mission. The three numbers to carry into the examination hall together are the date 19 April 2023, the outlay of 6,003.65 crore rupees and the period up to 2030-31.

The correct answer is B, 1984. Charles Bennett and Gilles Brassard proposed the protocol in that year, and the name BB84 combines their initials with the year. It describes how two parties can build a shared secret key by sending single photons in randomly chosen polarisation bases and then publicly comparing which bases they used, discarding the rest. Option A is wrong because 1974 is remembered in a different context, as the year the Basel Committee on Banking Supervision was formed, and has no bearing here. Option C is wrong because 1994 is the year Peter Shor published his factoring algorithm, which is a threat to classical cryptography rather than a protocol for securing it. Option D is wrong because 2004 is too late; by then quantum key distribution had already been demonstrated over fibre.

The correct answer is C, China. Micius was launched in 2016 and was used to demonstrate quantum key distribution between a satellite and ground stations, and entanglement distribution over distances far greater than optical fibre allows, since fibre loses photons rapidly over long runs. The satellite is named after an ancient Chinese philosopher. Option A is wrong because the United States has run major quantum programmes in computing and in post quantum cryptography but did not launch this satellite. Option B is wrong because Russia has no comparable dedicated quantum satellite to its name. Option D is wrong because Japan has done notable work on quantum communication over fibre but was not first to orbit. India's own target under the National Quantum Mission is satellite based secure quantum communication over 2,000 kilometres between ground stations.

The correct answer is D, quantum agriculture, which is not a recognised branch of the field and is not part of the mission. The four thematic areas, each with its own hub, are quantum computing at the Indian Institute of Science Bengaluru, quantum communication at the Indian Institute of Technology Madras, quantum sensing and metrology at the Indian Institute of Technology Bombay, and quantum materials and devices at the Indian Institute of Technology Delhi. Option A is wrong as an answer because quantum computing is the first of those areas. Option B is wrong because quantum communication, covering quantum key distribution over fibre and by satellite, is the second. Option C is wrong because quantum sensing and metrology, which produces atomic clocks, magnetometers and gravimeters, is the third. The fourth, materials and devices, supplies the hardware for the rest.