Ultra-fast random number generator uses quantum fluctuations

Variations driven by pairs of particles and antiparticles that form and then annihilate can be used to generate random numbers up to 200 times faster than available commercial devices can.

Using the inherent quantum flickering of empty space, researchers have figured out how to generate random numbers at an unprecedented rate. The record-breaking method could be used to enhance cryptographic security in large data centres.

Illustration of quantum vacuum fluctuations
Giroscience/Science Photo Library

Modern cryptography relies on the production of random numbers, which are used as keys to encrypt the vast stores of information produced by governments and businesses. Computer algorithms are often used to generate seemingly random numbers, but a sophisticated enough attacker could figure out what predetermined steps a computer is using and then predict its outputs.

A better approach would be to use some physical process that is truly random, says Cédric Bruynsteen at Ghent University in Belgium. The weird probabilistic nature of phenomena at the quantum scale is a gold standard that engineers often turn to, he says.

Empty space isn’t actually empty – it seethes with random fluctuations arising from pairs of particles and antiparticles that are spontaneously created and then crash together and destroy one another. While it looks like the universe is producing something from nothing, the process happens on extremely short timescales, leaving the overall energy of space unchanged.

Previous work has tapped into these quantum vacuum fluctuations to produce random numbers. But such systems are typically hamstrung by interfering noise coming from their own components, which slows the process.

To circumvent this, Bruynsteen and his colleagues built a special two-part computer chip and then carefully mapped all of its imperfections and sources of noise. This gave them the ability to discriminate sources of interference and measure the faint quantum vacuum fluctuation with far better sensitivity than prior attempts.

Such mapping, as well as the small size of their chip, which is just 5 millimetres long, allowed the researchers to speed up the process of reading out the random quantum fluctuation measurements, which could be done 10 times faster than any similar previous system, and up to 200 times faster than available commercial quantum random number generators.

The team is hoping to improve the technology by making it even smaller and faster, says Bruynsteen. Such a chip could one day find use in places such as hospitals and banks that need to encrypt large amounts of data securely, he adds.

“High-quality randomness is hard to get,” says Shih-Han Hung at the University of Texas at Austin, who wasn’t involved in the work. This means truly random numbers can be seen as a resource, so any effort to speed up their production is a benefit, he adds.

Journal reference:

PRX QuantumDOI: 10.1103/PRXQuantum.4.010330

Article amended on 24 March 2023

We clarified in the headline that this is the fastest random number generator of its type

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