The wave-particle duality observed in quantum mechanics is a fundamental aspect of the nature of particles at the quantum level. It is a consequence of the mathematical framework of quantum mechanics, which successfully describes the behavior of particles on a microscopic scale.
The reason why particles exhibit both wave-like and particle-like characteristics is deeply rooted in the probabilistic nature of quantum mechanics. At the quantum level, particles are described by wave functions, which are mathematical objects that encode the probability distribution of different outcomes when measuring a particle's properties.
When a particle is not being observed or measured, its wave function can exhibit wave-like behavior, meaning it spreads out and interferes with itself. This is analogous to the behavior of waves in classical physics. This wave-like behavior is mathematically described by the Schrödinger equation, the fundamental equation of quantum mechanics.
However, when a measurement is made to determine a particle's properties, the wave function collapses to a specific value, and the particle behaves more like a localized entity with definite properties. This is often referred to as the "collapse of the wave function" or the "measurement process."
It's important to note that the wave-particle duality is not a contradiction but rather a reflection of the probabilistic nature of quantum mechanics. It highlights the limitations of classical intuitions when dealing with the quantum world. The behavior of particles on the quantum level is inherently different from what we observe in our macroscopic everyday experience, where classical mechanics prevails.
While wave-particle duality can be challenging to conceptualize, it has been extensively tested and verified through numerous experiments, such as the double-slit experiment and the particle-wave duality of electrons and photons. Quantum mechanics, with its wave-particle duality, provides a remarkably accurate and successful framework for understanding and predicting phenomena on the quantum scale.