RRI technique yields Certified Randomness with one Qubit

Why in the News?

The Raman Research Institute (RRI), Bengaluru team has mastered the Leggett–Garg Inequality (LGI)–based quantum randomness certification technique.

What is Quantum Randomness?

• Overview: Quantum randomness means true unpredictability, results that even nature or science cannot predetermine. They arise from the laws of quantum physics, not from computer programs or hidden causes.
• Ordinary Computers: In normal computers, random numbers come from formulas called pseudorandom generators. They look random but can be predicted if someone knows the starting point (the “seed”).
• Quantum Systems: In quantum physics, when you measure something tiny, like the spin of an electron or the path of a light particle (photon), the result is decided only at the moment of measurement. No one, not even nature, “knows” the answer before that.
• Why it Matters: True randomness is important for data security, safe online transactions, scientific research, and encryption, where predictability can lead to hacking or errors.

What has RRI achieved?

• Discovery: Scientists at the Raman Research Institute (RRI), Bengaluru, led by Prof. Urbasi Sinha, have found a way to create and verify true quantum randomness using a regular cloud-based IBM quantum computer.
• Why it’s Important: Earlier, proving quantum randomness needed expensive lab equipment. Now it can be done remotely and cheaply, accessible to anyone with internet and quantum cloud access.
• How it Works: The RRI team used just one qubit (the quantum version of a computer bit) to show that the randomness came from quantum effects, not from hardware noise or computer errors.
• Key Finding: This demonstrates that even imperfect quantum computers can still generate trustworthy and verifiable random numbers, a capability that classical computers cannot achieve.

What is the Leggett–Garg Inequality (LGI)–Based Test?

• Basic Idea: The Leggett–Garg Inequality (LGI) is a scientific test that checks whether something behaves like everyday objects (predictable) or like quantum systems (unpredictable).
• How it was Used: The RRI scientists measured one qubit at three different times to see if its behavior followed normal physics or quantum rules.
• Two Conditions Checked:
  • LGI Violation – confirmed the qubit was behaving in a truly quantum way.
  • No Signalling in Time – ensured that each measurement was independent and not influenced by the previous one.
• Result: Meeting both tests proved that the numbers generated were certified as truly random, coming purely from quantum physics, not from any background noise or interference.

Real-life Applications:

• Cybersecurity: Such randomness can make unbreakable encryption keys, protecting sensitive data from hackers.
• Cloud Computing: People using quantum computers online can now access trusted random numbers for research or secure systems anywhere in the world.
• Testing Quantum Machines: Helps scientists check the quality of quantum computers, since randomness shows how genuinely quantum the machine is.
• Better Science: Used in simulations, artificial intelligence, and data analysis where unpredictability makes results more reliable.
• Big Scientific Message: Confirms that the quantum world is truly uncertain, proving one of the most fascinating truths of modern science, that randomness is built into nature itself.