Single-Qubit Quantum Method Delivers Certified Randomness

Context:

• Researchers at the Raman Research Institute (RRI) have demonstrated certified generation of random numbers using a single qubit, a significant advance in quantum technologies and cybersecurity.

• The work shows that existing quantum computers can already perform tasks that are fundamentally impossible for classical machines, with direct real-world applications.

Key Highlights:

What the Breakthrough Achieves

• Certified randomness generated using just one qubit, unlike earlier approaches requiring complex multi-qubit systems.

• Experiments were conducted on IBM’s superconducting quantum computers.

• Randomness was verified (certified) using violations of the Leggett–Garg inequality (LGI), a test rooted in quantum mechanics.

Why Randomness Matters

• Classical computers rely on pseudorandom number generators:

  • Algorithm-based

  • Ultimately predictable

  • Vulnerable in cryptography and secure communications

• Classical true random generators depend on physical processes but:

  • Can degrade over time

  • Require trust in hardware manufacturers

• Quantum randomness arises from intrinsic uncertainty in quantum measurements, offering provable unpredictability.

Scientific Principle Used: Leggett–Garg Inequality (LGI)

• LGI tests whether a system behaves classically or quantum mechanically over time.

• In the experiment:

  • The same single qubit was measured at three different times.

  • Consistent violation of LGI confirmed that outcomes could not be explained by classical theories.

• This violation certifies that the generated bits are truly random.

Experimental Design

• Simple quantum circuits were built on IBM’s quantum hardware.

• Measurements were taken using error-mitigation tools to improve reliability.

• Tests on IBM’s Brussels backend showed robust and repeatable LGI violations.

Why This is Important

• Demonstrates that:

  • Certified quantum randomness can be achieved without elaborate setups.

  • Even noisy, current-generation quantum devices are already useful.

• Enables:

  • Secure data encryption

  • Quantum-safe communications

  • High-quality simulations in science and engineering

Broader Scientific Significance

• Advances foundational physics by validating quantum theory in a new operational setting.

• Provides a benchmarking tool to test the quality of individual qubits.

• Bridges the gap between theoretical quantum mechanics and practical applications.

UPSC Relevance (GS-wise):

• GS Paper 3 – Science & Technology

  • Prelims:

    • Qubit, quantum computer, quantum randomness.

    • Difference between pseudorandom and true random numbers.

  • Mains:

    • Applications of quantum computing in cybersecurity.

    • Role of emerging quantum technologies in national security and data protection.

    • Significance of indigenous research institutions in frontier science.