Quantum Fluctuations Turned into Secure Random Numbers at IIST
Generating truly random numbers is crucial for secure online communication, but doing so in a reliable way is still a challenge. A research team from the Indian Institute of Space Science and Technology (IIST), Thiruvananthapuram — Anirudh Shekar, Chirang R. Patel, Jerin A. Thachil, and Prof. Ashok Kumar — has developed a new method that uses light to create highly secure random numbers.
The team used a process called four-wave mixing in rubidium-85 vapor to produce bright twin beams of light. The random variations in the brightness of these beams arise from quantum effects — the inherent unpredictability of nature at the microscopic level. While each beam fluctuates randomly on its own, the two beams show a strong link between their intensity changes. The researchers observed up to 95% correlation between the twin beams at 2 MHz, allowing them to create two synchronized random number streams — useful for quantum cryptography, where two users need shared randomness for secure communication.The system produced over 5 bits of true randomness per sample, reaching speeds of 6 megabits per second. The generated numbers passed strict international tests (NIST and TestU01) for randomness and security. Since the setup does not require an optical cavity, it is simpler, compact, and more stable. By showing how bright twin beams can be used to create fast and reliable random numbers, this work opens up a new path toward more secure data encryption and quantum communication technologies.
Image (1): Bright twin beams displayed on IR card with 95% correlation between their random intensity fluctuations.
Image (2): Prof. Ashok Kumar with his students Jerin A. Thachil and Chirang R. Patel at Quantum Optical Technology Lab at IIST.
Image (3): First Author Anirudh Shekar, dual degree (optical engineering) passed out of IIST in the year 2025
For more details:
https://pubs.aip.org/aip/apl/article/127/10/104002/3362441/Generation-o…