Photon bunching
Encyclopedia
In physics
, photon bunching refers to the statistical tendency for photons to distribute themselves in bunches (super-Poissonian statistics) rather that at random (Poissonian
). Thermal fields are examples of photon bunching. Their statistic can be observed as photons that arrive more simultaneously (positive correlation) at detectors. This can disturb our understanding of classical particles
, which tells us that non-interacting particles should know nothing about each other, and so should arrive independently of one another. This apparent contradiction is explained by recognizing this not as a particle effect, but rather as a wave
effect. Photon bunching is predicted by quantum mechanics
, and manifests experimentally in the Hanbury-Brown and Twiss effect
, which itself can be understood classically as a pure wave effect.
Physics
Physics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...
, photon bunching refers to the statistical tendency for photons to distribute themselves in bunches (super-Poissonian statistics) rather that at random (Poissonian
Poisson distribution
In probability theory and statistics, the Poisson distribution is a discrete probability distribution that expresses the probability of a given number of events occurring in a fixed interval of time and/or space if these events occur with a known average rate and independently of the time since...
). Thermal fields are examples of photon bunching. Their statistic can be observed as photons that arrive more simultaneously (positive correlation) at detectors. This can disturb our understanding of classical particles
Elementary particle
In particle physics, an elementary particle or fundamental particle is a particle not known to have substructure; that is, it is not known to be made up of smaller particles. If an elementary particle truly has no substructure, then it is one of the basic building blocks of the universe from which...
, which tells us that non-interacting particles should know nothing about each other, and so should arrive independently of one another. This apparent contradiction is explained by recognizing this not as a particle effect, but rather as a wave
Wave
In physics, a wave is a disturbance that travels through space and time, accompanied by the transfer of energy.Waves travel and the wave motion transfers energy from one point to another, often with no permanent displacement of the particles of the medium—that is, with little or no associated mass...
effect. Photon bunching is predicted by quantum mechanics
Quantum mechanics
Quantum mechanics, also known as quantum physics or quantum theory, is a branch of physics providing a mathematical description of much of the dual particle-like and wave-like behavior and interactions of energy and matter. It departs from classical mechanics primarily at the atomic and subatomic...
, and manifests experimentally in the Hanbury-Brown and Twiss effect
Hanbury-Brown and Twiss effect
The Hanbury Brown and Twiss effect is any of a variety of correlation and anti-correlation effects in the intensities received by two detectors from a beam of particles. HBT effects can generally be attributed to the dual wave-particle nature of the beam, and the results of a given experiment...
, which itself can be understood classically as a pure wave effect.