Wave-particle duality is a fundamental principle of quantum mechanics that applies to particles at the quantum level. It implies that particles, such as electrons, protons, and even larger particles like atoms and molecules, can exhibit both wave-like and particle-like behavior.
While wave-particle duality is most prominently observed and studied at the microscopic level, such as with electrons and photons, its principles are not limited to a specific size range. The manifestation of wave-particle duality depends on the de Broglie wavelength associated with a particle, which is determined by its momentum and mass.
Generally, the de Broglie wavelength becomes significant and observable when the size or momentum of a particle approaches the quantum scale. This typically occurs with particles at the micro and nano scales, but it can also apply to larger particles under certain conditions.
For example, experiments have demonstrated the wave-like behavior of large molecules consisting of hundreds or thousands of atoms, showcasing interference patterns similar to those observed in the double-slit experiment. This indicates that wave-particle duality extends to larger systems under specific circumstances.
However, as the size and complexity of a system increase, the wave-like behavior becomes less pronounced and is often overshadowed by classical behavior due to the effects of decoherence and interactions with the surrounding environment. This is why the wave-particle duality is most prominently observed and studied with particles at the micro and nano scales, where quantum effects dominate.
In summary, wave-particle duality is a fundamental principle that applies to particles across different size scales, but its effects are most pronounced and experimentally observable at the micro and nano scales. As particle systems increase in size and complexity, classical behavior tends to dominate over wave-like behavior due to decoherence and interactions with the environment.