According to the principles of quantum mechanics and the wave-particle duality, a single quantum entity, such as a photon or an electron, can exhibit characteristics of both a wave and a particle. This duality arises from the wave-like behavior of quantum entities and their discrete, particle-like interactions.
In certain experiments, quantum entities behave as if they were waves. For example, in the famous double-slit experiment, when individual particles are sent through two slits and allowed to interfere with themselves, they create an interference pattern on a screen behind the slits, similar to what would be expected of waves. This wave-like behavior suggests that quantum entities have a wave nature.
On the other hand, quantum entities also exhibit particle-like behavior. For instance, when measuring the position or momentum of a quantum entity, it behaves as if it were a localized particle, showing distinct values at specific positions or with definite momenta. Additionally, the photoelectric effect, where photons eject electrons from a metal surface, can be explained by treating photons as discrete particles.
Therefore, a single quantum entity can be seen as having both wave and particle features. It is important to note that this duality is not a classical analog but a fundamental property of quantum mechanics. The behavior of quantum entities is best described using mathematical formalisms, such as wavefunctions and superposition, which allow us to predict the probabilities of different outcomes in experiments.