Quantum Computing: Principles, Applications, and India's National Quantum Mission
July 19, 202612 min read
The question reads: "Consider the following statements regarding Quantum Computing:"
A qubit is not just a faster bit - it is a fundamentally different information unit that exploits superposition and entanglement. Classical computers process bits (0 or 1). Quantum computers process qubits (0, 1, or both simultaneously). For UPSC, the science is tested at conceptual level (Prelims) and the policy at application level (Mains). India's National Quantum Mission - ₹6,003 crore across 8 years - aims to build a 50-100 qubit quantum computer by 2028, but the global leaders (IBM, Google) already have 1000+ qubits. Where does India stand?
[TOPIC CLASSIFICATION]
Topic type: Emerging Technology (Quantum Science, Computing, and National Policy)
PYQ frequency: Low-Medium (growing. 1-2 questions per year since 2023, expected to increase with NQM implementation)
Primary GS paper: GS-3 (Science and Technology - emerging technologies, applications, and policy)
[EXAMINER REASONING]
Trap: Confusing mission objectives, launch vehicles, or technological capabilities. Examiners test precise technical terminology.
Most confused: The distinction between civilian and strategic (dual-use) technology, and between indigenous development vs licensed production vs import.
Key anchor: The institutional architecture (ISRO, DRDO, DAE, CSIR, ICMR, DBT, MeitY) and policy framework (Space Policy, Nuclear Doctrine, Biotechnology Guidelines, National AI Strategy, Drone Rules).
Current affairs hook: Major missions (Chandrayaan-3, Aditya-L1, Gaganyaan), new policy initiatives (IN-SPACe, iDEX, Semiconductor Mission, Quantum Mission, AI Mission), defence tests (Agni, S-400, ARIHANT), health tech (mRNA, vaccines).
Mains hinge: Frame answers around the core tension - self-reliance vs international cooperation, strategic autonomy vs technology access, security vs transparency, innovation vs regulation.
Core Concept
What is Quantum Computing?
Quantum computing exploits quantum mechanical phenomena - superposition, entanglement, and interference - to process information in ways impossible for classical computers. Where a classical bit is 0 or 1, a qubit (quantum bit) can be in a superposition of both states simultaneously. Entanglement links qubits so that operations on one affect the other, enabling exponential parallelism.
How it works: A quantum algorithm prepares qubits in a superposition of all possible solutions. Quantum interference amplifies correct solutions and cancels incorrect ones. A measurement collapses the superposition - yielding the correct solution with high probability. This is probabilistic, not deterministic - quantum computations are repeated multiple times to confirm the answer.
Current quantum computing technologies (qubit modalities):
Modality
Technology
Leading players
Qubit count (2026)
Challenges
Superconducting
Current loops in superconducting circuits, cooled to near absolute zero (~15 mK)
IBM, Google, Rigetti (US)
1000+
Requires extreme cooling; short coherence time
Trapped ions
Individual ions trapped by electromagnetic fields, manipulated by lasers
IonQ, Quantinuum (US), Alpine Quantum (Austria)
50-100
Slower gate speed; high fidelity
Photonic
Photons as qubits, operate at room temperature
Xanadu (Canada), PsiQuantum (US)
Scalable in principle
Photon loss - hard to maintain entanglement
Neutral atoms
Atoms trapped in optical tweezers
QuEra, Atom Computing (US)
1000+ (neutral atoms)
Lower gate fidelity
Topological
Braided quasiparticles - theoretically error-free
Microsoft (US)
Proof-of-concept only
Not yet demonstrated experimentally
India's National Quantum Mission (NQM):
Launched April 2023 by the Ministry of Science and Technology. ₹6,003.65 crore outlay (2023-2031). Four thematic hubs (T-Hubs) established at IISc Bangalore, IIT Bombay, IIT Delhi, and IIT Jodhpur.
Pillar
Budget (₹ cr)
Target
Lead institution
Quantum Computing
~1,500
50-100 physical qubits by 2028; fault-tolerant quantum computer by 2031
IISc Bangalore (hub), IIT Bombay, IIT Madras
Quantum Communication
~1,200
Quantum Key Distribution network over 2000+ km; satellite-based QKD (similar to China's Micius)
IIT Delhi (hub), IIT Kharagpur
Quantum Sensing
~800
Atomic clocks, quantum magnetometers, gravity sensors for defence and navigation
IIT Jodhpur (hub), RRI Bangalore
Quantum Materials & Devices
~1,500
Indigenously developed qubit platforms (superconducting, photonic, trapped ion)
Global quantum race (cumulative government investment, 2026): China: $15B+ (including $10B Hefei National Laboratory for quantum), USA: $5B+ (National Quantum Initiative Act 2018, CHIPS & Science Act 2022), EU: €7B (Quantum Flagship), UK: £1B, Japan: $1B, India: $750M equivalent (₹6,003 crore). India's investment is ~5% of China's.
India's position: India has strong theoretical quantum physics research (Raman Research Institute, HRI, IISc, TIFR) but limited experimental capability (qubit fabrication requires nanofabrication cleanrooms and dilution refrigerators - the NQM is building these capabilities for the first time). India has commercial capability in quantum communication (QNu Labs, Bengaluru - one of ~15 companies globally with QKD products) but zero capability in quantum computing hardware. The NQM targets 50-100 qubits by 2028 - comparable to IBM's qubit count in 2019-2020, putting India ~8-10 years behind the global frontier.
Key Facts
NQM launch: April 2023 (2023-2031), ₹6,003 crore total outlay
Threat timeline: Post-quantum cryptography transition required by 2030-2035 - NIST has finalized 3 post-quantum encryption standards (2024) including CRYSTALS-Kyber and CRYSTALS-Dilithium
China advantage: Micius satellite (2016) - first quantum communication satellite; Beijing-Shanghai QKD backbone (2000+ km); Hefei National Lab ($10B)
UPSC Question Themes (Illustrative)
Treat these as original practice prompts unless a linked official UPSC paper is provided; they are not represented as verbatim PYQs.
| Type | Stage | What was tested |
|------|-------|-----------------|
| Practice | Prelims | Qubit - meaning and properties (superposition, entanglement) |
| Practice | Mains GS-3 | "Quantum computing poses both opportunities and threats to national security." Discuss in the context of India's preparedness. |
| Practice | Prelims | Shor's algorithm - what it threatens (RSA encryption) |
| Practice | Mains GS-3 | "India's National Quantum Mission has the right objectives but inadequate funding." Critically evaluate. |
| Practice | Prelims | National Quantum Mission - launch year, outlay, and objectives |
| Practice | Mains GS-3 | "Emerging technologies like quantum computing are reshaping global power dynamics." Examine India's strategic response. |
| Practice | Prelims | Difference between classical bits and qubits |
| Practice | Prelims | Quantum entanglement - meaning and applications |
Statement Elimination Guide
"Quantum computers can solve any computational problem faster than classical computers." False. Quantum computers excel only at specific problem classes: integer factorisation (Shor's), unstructured search (Grover's), quantum simulation, and certain optimisation problems. For most everyday computing (word processing, web browsing, video rendering), quantum computers offer no advantage - and are much slower due to overheads of cooling and error correction.
"India's National Quantum Mission aims to build a 1000-qubit quantum computer by 2028." False. The NQM targets 50-100 physical qubits by 2028 and a fault-tolerant quantum system by 2031. The target is modest compared to global leaders (IBM already has 1000+ qubits) because India is building foundational infrastructure for the first time - cleanrooms, cryogenic facilities, and trained workforce.
"Quantum communication through Quantum Key Distribution (QKD) is theoretically unbreakable." Correct. QKD uses the quantum no-cloning theorem - any attempt to eavesdrop on a quantum communication collapses the quantum state, alerting both parties. This makes QKD theoretically secure against any computational attack (including quantum computers). However, practical QKD systems have vulnerabilities in hardware implementation that are being addressed.
"The National Quantum Mission covers only quantum computing." False. The NQM has four pillars: quantum computing, quantum communication, quantum sensing and metrology, and quantum materials & devices. Each pillar has a dedicated T-Hub and budgetary allocation. Quantum computing receives the largest share (~25%) but not an exclusive mandate.
"Post-quantum cryptography refers to running encryption algorithms on quantum computers." False. Post-quantum cryptography (PQC) refers to classical cryptographic algorithms that are resistant to attacks by quantum computers. These are new mathematical constructions (lattice-based, code-based, hash-based) that run on classical computers but cannot be broken by Shor's algorithm. NIST has standardized three PQC algorithms (2024). India's crypto-agility programme is under development by CERT-In.
Current Affairs Hook
Three developments define the quantum landscape in 2026. First, Google's Willow chip (December 2024) achieved below-threshold error correction - the main roadblock to practical quantum computing. Willow's 105 qubits operate with error rates low enough that adding more qubits reduces overall error. This is the "break-even" milestone that quantum computing researchers have pursued since Peter Shor proposed error correction in 1995. Commercial fault-tolerant quantum computing is now projected within 5-7 years, not 15-20.
Second, NIST finalized three post-quantum cryptographic standards in August 2024 - CRYSTALS-Kyber (key encapsulation), CRYSTALS-Dilithium (digital signatures), and SPHINCS+ (stateless signatures). In 2026, the US National Security Agency (NSA) mandated transition of all US government systems to PQC by 2035. CERT-In issued an advisory in early 2026 recommending Indian government agencies and critical sectors begin PQC transition planning.
Third, the NQM's mid-term review (2026) reported that India's quantum communication pillar is ahead of schedule - IIT Delhi demonstrated QKD over 200 km of standard commercial fibre (March 2026), and satellite-based QKD payload development (ISRO in collaboration with IIT Delhi) is on track for 2028 launch. However, the quantum computing pillar is behind - India's first superconducting qubit testbed (at IIT Bombay) produced its first functional qubit in 2025, but with fidelity below the minimum threshold for practical computation. The review recommended increased international collaboration (particularly with IBM and Quantinuum for technology transfer) and a supplementary allocation of ₹1,500 crore.
Interlinkages
Internal Security (GS-3): Quantum computing threatens current encryption standards. India's UPI infrastructure (over 14B transactions monthly), Aadhaar (1.4B identities), and banking networks all rely on RSA and ECC encryption - both vulnerable to Shor's algorithm. CERT-In's 2025 "harvest now, decrypt later" warning highlights the risk of State actors collecting encrypted Indian data today for decryption once quantum computers mature. India must develop crypto-agility - the ability to switch encryption standards quickly.
Defence (GS-3): Quantum sensing applications for defence: quantum magnetometers can detect submarines underwater (by measuring magnetic field anomalies); quantum radar (quantum illumination) can detect stealth aircraft; atomic clocks improve GPS-denied navigation for submarines and missiles. DRDO has established a quantum technology vertical (DRDO QT Division, 2024) with a ₹500 crore budget for defence quantum applications.
Space (GS-3): ISRO's quantum payload programme (2028 target) will enable secure satellite communication through QKD. India's NavIC satellite navigation system could be enhanced with quantum atomic clocks for greater accuracy. ISRO is collaborating with IIT Delhi and Raman Research Institute on space-grade quantum experiments.
Economy (GS-3): McKinsey projects quantum computing will create $450B-$850B in economic value by 2040. India's IT services sector ($250B revenue) faces both opportunity (quantum services) and threat (disruption of existing computing models). Infosys, TCS, and Wipro have established quantum research labs. The Indian quantum startup ecosystem is nascent but growing.
International Relations (GS-2): India has bilateral quantum partnerships with US (iCET framework - joint quantum research on photonics and error correction, 2024), Japan (Quantum-India-Japan platform, 2025), and Israel (quantum sensing and communication MoU, 2024). India has not joined the Quantum Alliance (US, UK, Japan, Canada, EU, 2024) - but participates in the Quad's Critical and Emerging Technology (CET) working group on quantum.
Common Mistakes
"Quantum computers will replace all classical computers." No. Quantum computers are special-purpose devices. Classical computers will continue to handle most computing tasks. The future is hybrid - classical computers orchestrate quantum computers for specific sub-tasks (like a GPU handles graphics).
"A qubit is the same as a classical bit, just faster." No. A qubit uses superposition to exist in multiple states simultaneously. Two qubits can represent 4 states, three qubits = 8 states, n qubits = 2ⁿ states. This is exponential parallelism - fundamentally different from classical computing.
"India has a functioning quantum computer." No. India's NQM targets 50-100 qubits by 2028. No Indian institution (academic or corporate) currently has an operational quantum computer with practical capability. India's quantum startups offer quantum simulation (running on classical hardware) and quantum communication - not quantum computing hardware.
"Quantum Key Distribution (QKD) is a form of quantum computing." No. QKD is quantum communication - it uses quantum properties to secure communication channels, not to process information. The NQM has separate pillars for computing and communication.
"The NQM's ₹6,003 crore is comparable to global investments." No. China has invested $15B+ in quantum R&D - 20x India's commitment on a PPP-adjusted basis. India's NQM is 0.2% of the current account surplus India generates annually. Critics argue it is inadequate for a technology that will be as transformative as the internet.
Revision Snapshot
Quantum computing: processes information using qubits (superposition, entanglement, interference). Key algorithms: Shor's (breaks RSA encryption), Grover's (searches databases quadratically faster), quantum simulation (drugs, materials). Qubit technologies: superconducting (IBM, Google - 1000+ qubits), trapped ions (IonQ - highest fidelity), photonic (room temperature), neutral atoms (QuEra - 1000+ qubits). India's NQM (2023-2031, ₹6,003 crore, 4 T-Hubs): targets 50-100 physical qubits by 2028, QKD network over 2000+ km, quantum sensors for defence. India has strong quantum theory but limited experimental capability - ~8-10 years behind global frontier. NIST standardized three post-quantum crypto algorithms (2024). Global quantum market growing from $7B (2025) to $65B (2030). Strategic stakes: encryption vulnerability, defence sensing, space communication, economic value. UPSC takeaway: distinguish quantum computing vs communication vs sensing; know NQM targets; understand Shor's algorithm threat to encryption; track India's modest position in the global quantum race.
Source Notes
Department annual reports (Space, Atomic Energy, Defence R&D, Biotechnology, S&T)
ISRO, DRDO, DAE, CSIR, ICMR, DBT, MeitY official publications