The prediction that all matter can behave as both waves and particles is a fundamental concept in quantum mechanics and can be attributed to several physicists who made significant contributions to the development of the theory.
The wave-particle duality was first proposed by Louis de Broglie in his doctoral thesis in 1924. De Broglie hypothesized that particles, such as electrons, which were previously thought to be purely particles, could also exhibit wave-like behavior. He associated a wave-like property called the "matter wave" or "de Broglie wave" with particles, proposing that their wavelength is inversely proportional to their momentum. This idea was later confirmed experimentally through various diffraction and interference experiments.
Building upon de Broglie's work, Werner Heisenberg and Erwin Schrödinger formulated the mathematical framework of quantum mechanics, known as wave mechanics or Schrödinger's wave equation, in the late 1920s. This framework describes the behavior of particles in terms of wave functions, which are mathematical functions that represent the probability amplitudes of different possible states of a particle.
Another key figure in the development of quantum mechanics was Max Born, who in 1926 proposed the interpretation of the wave function as a probability amplitude. Born's interpretation related the squared magnitude of the wave function to the probability distribution of finding a particle at different positions when measured.
These contributions, along with the work of other physicists such as Niels Bohr, Paul Dirac, and others, collectively established the wave-particle duality as a cornerstone of quantum mechanics and revolutionized our understanding of the behavior of matter and radiation at the microscopic level.