Random numbers underpin a surprising amount of modern society (background information here) but unfortunately both humans and computers alike are poor at generating random numbers (read here about problem definition). Thankfully quantum physics is inherently random and researchers from Lancaster University, in collaboration with Quantum Base, have developed a simple solution to this important problem.
Fundamental particles like electrons and photons do not obey the laws of classical physics, instead we need to use quantum mechanics to describe them. To understand the difference between classical and quantum physics let’s consider a simple example.
In classical physics, if I shine light on a partially reflective surface, like a piece of glass, the light splits into two components – some travels through the glass and some is reflected from it.
The same experiment in quantum physics is subtly different. Light is stream of fundamental particles, photons. When they meet a partially-reflective surface they can’t be divided, instead they are reflected or transmitted with a certain probability. This is a key aspect of quantum mechanics, it describes everything in terms of probabilities.
This is, it turns out, very useful for generating random numbers. Consider the arrangement in Figure 1: