The wave-particle duality in quantum mechanics is a fundamental aspect of the theory that describes the behavior of particles at the microscopic level. It is supported by a vast body of experimental evidence and has been confirmed through numerous experiments and observations.
One of the key experiments that provided early evidence for the wave-particle duality was the famous double-slit experiment. In this experiment, particles such as electrons or photons are sent through a barrier with two slits and are detected on a screen behind the barrier. The surprising result is that even when individual particles are sent through the apparatus one at a time, they still produce an interference pattern on the screen, as if they were interfering with themselves. This interference pattern is characteristic of waves, not particles.
This experiment, along with other similar experiments, demonstrates that particles exhibit wave-like behavior. The wave-like nature of particles is further supported by the mathematical formalism of quantum mechanics, which describes particles using wavefunctions. The wavefunction describes the probability amplitude distribution of a particle, and its behavior is governed by the Schrödinger equation.
In the quantum field theory framework, particles are described as excitations of underlying quantum fields. Quantum fields permeate all of spacetime, and particles arise as quantized excitations or disturbances in these fields. The behavior of these fields and their excitations is wave-like, as described by mathematical equations such as the Klein-Gordon equation, the Dirac equation, or the quantized versions of these equations in the context of quantum field theory.
In classical wave-particle duality, the behavior of particles and waves is described by different theories. For example, in classical physics, light is described as a wave, and particles such as electrons are described as point-like particles with definite trajectories. In quantum mechanics, however, both particles and waves are described by a unified theory, where particles exhibit wave-like properties and waves can exhibit particle-like properties.
This distinction between classical wave-particle duality and quantum wave-particle duality is rooted in the fundamental differences between classical physics and quantum mechanics. Quantum mechanics introduces probabilistic interpretations, superposition of states, and the uncertainty principle, which give rise to the wave-like behavior of particles and the notion of wave-particle duality.
In summary, the wave-particle duality of particles in a quantum field is supported by experimental evidence and the mathematical formalism of quantum mechanics. It differs from classical wave-particle duality in that quantum mechanics unifies the description of particles and waves, where particles exhibit wave-like behavior and waves can exhibit particle-like properties.