Photon Interferences: History and Fundamental Aspects

Jincheng Zhang

In conventional theories of light transport, the state of a photon at a given instant depends solely on its present position and momentum, with the past trajectory playing no explicit role in determining subsequent evolution. This assumption underlies classical geometrical optics, wave optics, and most quantum electrodynamics treatments of photon propagation in linear media. Here we challenge this paradigm by proposing that the probability amplitude of finding a photon at time t, denoted P(t), can be an explicit functional of the entire preceding path, expressed as P(t) = F(s_1, s_2, ..., s_K), where each s_k represents a discrete segment of the photon's trajectory or an interaction event. We develop a theoretical framework that incorporates a history-dependent kernel into the photon transport equation, thereby unifying wave, ray, and statistical descriptions. The model predicts novel interference patterns, modified group velocities, and nonlocal correlations that could be observed in complex photonic structures and quantum interference experiments. We explore the implications of this history effect for quantum optics, including potential enhancements in quantum communication protocols and new mechanisms for controlling photon entanglement. The PPHE offers a fresh perspective on the fundamental nature of light propagation, suggesting that photons may retain a memory of their past that influences their future, with significant ramifications for both fundamental physics and practical photonic engineering.

Varun S Bhatta

John Gordon King, Malcolm Correll

M. Beck, Enrique J. Galvez

We describe several experiments which use individual photons and entangled photon pairs to explore fundamental aspects of quantum mechanics in an undergraduate teaching laboratory. These experiments include single photon interference and tests of local realism.

Pieter Kok

Andreas Norrman, Kasimir Blomstedt, Tero Setälä +2 more

We study partial coherence and polarization in double-pinhole photon interference and establish two general complementarity relations for genuine vectorial quantum-light fields. The framework uncovers new fundamental aspects of photon wave–particle duality.