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Quantum statistics of light
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Photons obey Bose–Einstein statistics.
Photons are bosons, so thermal light has Bose–Einstein statistics: bunching of detection events. Laser light has Poisson statistics, and single photons show antibunching.
Hanbury Brown–Twiss experiment.
Distinguishes classical and nonclassical light.
In more detail
Quantum statistics of light describe fluctuations in photon numbers. Coherent light, such as from lasers, has Poissonian statistics, while thermal light is more bunched.
Real-world uses
- Quantum optics uses photon statistics to test quantum theory.
- Quantum communication uses single-photon sources with non-classical statistics.
- Quantum optics researchers use the Bose–Einstein statistics of photons to describe laser and thermal light.
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Frequently asked questions
What is photon bunching?
Photons tend to arrive together, as in thermal light, which shows stronger fluctuations.
Why does it matter?
It distinguishes quantum light from classical light in experiments.
Why do photons bunch together?
Bosons tend to occupy the same state, which makes thermal light more bunched than laser light.
Related topics in Quantum Mechanics
Population inversion · Einstein coefficients · Blackbody and Planck's law · Quantum field theory intro · Feynman path integral · Quantum electrodynamics