Yes, there is a unified theory that explains both the wave and particle properties of light. This theory is known as quantum electrodynamics (QED). QED is a quantum field theory that describes the interactions of light (electromagnetic radiation) with charged particles, such as electrons and positrons.
According to QED, light can be understood as a stream of particles called photons, which exhibit particle-like behavior. These photons carry discrete packets or quanta of energy. However, at the same time, QED also describes light as an electromagnetic wave, characterized by properties such as wavelength, frequency, and amplitude. This wave-like behavior is associated with the probabilistic nature of quantum mechanics.
In QED, the interaction between photons and charged particles is mediated by virtual particles, such as virtual electrons and positrons, which briefly come into existence and then annihilate. These virtual particles allow for the exchange of energy and momentum between photons and charged particles, resulting in the observed phenomena of absorption, emission, scattering, and interference.
Quantum electrodynamics is a fundamental theory that successfully combines quantum mechanics and electromagnetic theory, providing a comprehensive framework for understanding the wave-particle duality of light and its interactions with matter.