When we say that elementary particles are "waves," we are referring to the wave-particle duality, a fundamental concept in quantum mechanics. According to this concept, particles such as electrons, protons, and photons can exhibit both wave-like and particle-like characteristics, depending on how they are observed or measured.
The wave-like nature of particles is described mathematically by wavefunctions, which are solutions to the fundamental equations of quantum mechanics, such as the Schrödinger equation. These wavefunctions represent the probability distribution of finding a particle in different states or locations.
Wave-like behavior is characterized by several properties:
Superposition: A particle can exist in a superposition of multiple states simultaneously. This means that it can be in a combination of different energy levels, positions, or other quantum properties, with each state having a certain probability.
Interference: Similar to classical waves, quantum waves can interfere constructively or destructively. This interference is observed when the wavefunctions of particles overlap, leading to the formation of interference patterns.
Diffraction: Particles can exhibit diffraction, which is the bending or spreading out of a wave as it encounters an obstacle or passes through a narrow slit. This behavior is observed in experiments such as electron or neutron diffraction, where particles exhibit wave-like patterns.
Wavepacket: While waves can be spread out over a large region, particles are often observed localized in space. The wavepacket represents a localized group of waves that describes the position and momentum of a particle more precisely.
It is important to note that while particles can exhibit wave-like properties, they also exhibit particle-like behavior in certain experiments and observations. For example, particles can be detected as discrete entities with well-defined positions or momenta. This dual nature is a fundamental aspect of quantum mechanics and has been extensively tested and confirmed through various experiments.