Hanbury Brown-Twiss effect

The Hanbury Brown-Twiss effect involves measuring correlations between particles, such as photons, arriving at detectors. When particles are emitted from a source, quantum mechanics causes them to exhibit a tendency to arrive together or "bunch," especially if they are identical. This correlation reveals information about the source’s size and shape. Essentially, the effect demonstrates how the statistical properties of particles’ arrivals can be used to infer details about their origin, highlighting the quantum nature of light and particles in a way that classical physics cannot explain.