IIT-Delhi’s Quantum Communication Feat

22 Jun 2025 GS 3 Science & Technology
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  • On June 16, 2025, IIT-Delhi and DRDO successfully demonstrated quantum communication over 1 km in free space using entanglement-based Quantum Key Distribution (QKD).

  • This is a significant step toward secure satellite-based quantum communication.

What is Quantum Communication?

  • Uses principles of quantum physics, especially quantum entanglement, to make communication channels leak-proof and tamper-evident.

  • Quantum entanglement: Measurement of one entangled photon instantly affects its pair, no matter the distance.

  • Any third-party interception disturbs the entangled state, revealing the breach.

What is Quantum Key Distribution (QKD)?

  • QKD is a method to securely share encryption keys using quantum properties.

  • It does not encrypt messages, but ensures that both sender and receiver share an identical, secure key.

  • Two types of QKD:

    1. Prepare-and-measure QKD: Photons are sent in predetermined states.

    2. Entanglement-based QKD: Entangled photon pairs are shared between two parties.

IIT-Delhi's Key Achievements

  • Demonstrated entanglement-based QKD in open air over 1 km on campus.

  • Achieved:

    • Secure key rate of ~240 bits/second

    • Quantum bit error rate (QBER) of <7% (acceptable standard)

  • Previous milestones:

    • Vindhyachal–Prayagraj link (2022)

    • 100+ km optical fibre QKD (2024)

Future Aspirations

  • Aim to extend QKD between ground stations and satellites, enabling:

    • All-India secure key distribution

    • Defense-grade quantum communication networks

  • Long-term vision: A multi-node quantum communication network across India.

National Quantum Mission

  • Launched in 2023, with ₹6,000 crore budget till 2031.

  • Focus on:

    • Quantum computing

    • Quantum sensing/metrology

    • Quantum materials

    • Quantum communication

Applications of Quantum Communication

SectorUse
Defense & IntelligenceSecure communication; cyber warfare readiness
BankingEnd-to-end secure transaction systems
TelecomTamper-proof data networks
Space & SatellitesGround-to-satellite key distribution
CybersecurityProtection from quantum computer-based attacks

Challenges

  • Free-space QKD affected by:

    • Air turbulence

    • Detector noise

    • Artificial lighting

  • Scaling from lab to national and satellite level requires:

    • Precision optics

    • Robust quantum repeaters

    • Efficient photon detectors

Significance

  • Marks India's entry into the global quantum communication race.

  • Strategic importance for national security, data privacy, and technological sovereignty.

  • Aligns with India’s push for Atmanirbhar Bharat in high-tech sectors.



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