Wave-particle duality is indeed a fundamental concept in quantum mechanics, which is the branch of physics that describes the behavior of matter and energy at the smallest scales. It suggests that particles, such as electrons and photons (particles of light), can exhibit both wave-like and particle-like properties under different experimental conditions.
The wave-particle duality arises from the mathematical framework of quantum mechanics, which uses wave functions to describe the behavior of particles. These wave functions can exhibit wave-like characteristics, such as interference and diffraction, as well as particle-like characteristics, such as localized measurements of position and momentum.
In the case of light, it was initially believed to behave solely as a wave due to its ability to exhibit phenomena like interference and diffraction. However, experiments such as the photoelectric effect and the observation of discrete energy levels in atomic spectra demonstrated that light also exhibits particle-like behavior. These findings led to the development of the concept of photons as particles of light.
It's important to note that the notion that particles are "illusions" is not an accurate interpretation of wave-particle duality. Rather, it suggests that particles and waves are two complementary descriptions of the same underlying quantum entity. Depending on the experimental setup and the type of measurement being performed, the behavior of a particle may manifest as wave-like or particle-like.
Wave-particle duality has been extensively verified through numerous experiments and is considered a fundamental aspect of quantum mechanics. It is a concept that has provided deep insights into the nature of matter and energy at the quantum level.