DRDO & IIT Delhi Achieve Quantum Entanglement-Based Free-Space Communication | Current Affairs | Vision IAS
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    DRDO & IIT Delhi Achieve Quantum Entanglement-Based Free-Space Communication

    Posted 17 Jun 2025

    2 min read

    The free-space quantum secure communication was demonstrated over a distance of ~1 km via a free-space optical link.

    • ISRO demonstrated 1st free-space QKD over 300m in 2021.

    About the experiment

    • It was part of the ‘Design and development of photonic technologies for free space Quantum Key Distribution (QKD)’ of DRDO.
    • The experiment exhibited a very low quantum bit error rate (QBER) of less than 7%.
      • QBER is the error between the information sent and received and an indicator of the probability of eavesdropping.
    • It paves the way for real-time applications in quantum cybersecurity, long-distance QKD, and the future quantum internet.

    What is QKD?

    • Communication Technology: It is a Quantum Communication technology based on quantum mechanics, that is, quantum entanglement and cryptography.
      • Quantum mechanics explains how extremely small objects simultaneously have the characteristics of both particles and waves (a disturbance or variation that transfers energy). 
        • Physicists call this the “Wave-Particle Duality.”
    • Key Principles: 
      • Quantum entanglement: Particles of the same origin, which were once connected, always stay connected, even when separated by vast distances.
      • Quantum cryptography: encryption to secure and transmit data in a way that cannot be hacked.

    Benefits of Entanglement-Based QKD

    • Functionality: Secure key distribution even if devices are compromised or imperfect.
    • Detection of eavesdropping: Any attempt to measure or intercept the entangled photons disturbs the quantum state. 
    • Free-space QKD: No need for expensive fibre-optic cables—ideal for tough terrain and dense cities. 
    • Tags :
    • Quantum Mechanics
    • Quantum Entanglement
    • QKD
    • Wave-Particle Duality
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