Wave-Particle Duality

wave-particle duality

Principle that subatomic particles possess some wavelike characteristics, and that electromagnetic waves, such as light, possess some particlelike characteristics. In 1905, by demonstrating the photoelectric effect, Albert Einstein showed that light, which until then had been thought of as a form of electromagnetic wave (see electromagnetic radiation), must also be thought of as localized in packets of discrete energy (see photon). In 1924 Louis-Victor Broglie proposed that electrons have wave properties such as wavelength and frequency; their wavelike nature was experimentally established in 1927 by the demonstration of their diffraction. The theory of quantum electrodynamics combines the wave theory and the particle theory of electromagnetic radiation.

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wave-particle duality

The inherent contradiction in the way energy behaves. At the turn of the 20th century, it was believed that light was electromagnetic waves and electrons were particles. By the 1930s, it was determined that light behaves as if it were made up of particles (photons) as well as waves, and electrons also behave like waves. This has driven scientists to drink and is one of the most puzzling phenomena in the universe. See quantum mechanics.

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wave-particle duality [′wāv ′pärd·ə·kəl dü′al·əd·ē]

(quantum mechanics)

The principle that both matter and electromagnetic radiation exhibit phenomena in which they behave as waves and other phenomena in which they behave as particles, the two aspects being associated by the de Broglie relations. Also known as duality principle; wave-corpuscle duality.

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Wave-Particle Duality 

a proposition central to quantum mechanics that the behavior of microobjects exhibits both corpuscular and wave characteristics.

In accordance with the concepts of classical (nonquantum) physics, the motion of particles and the propagation of waves differ in principle. However, experiments on the ejection of electrons from metal surfaces by light (photoelectric effect), the study of the scattering of rays by electrons (Compton effect), and a number of other experiments have convincingly demonstrated that light and X-rays, which, according to classical theory, have a wave nature, behave similarly to a flux of particles. A “particle” of light (photon) has an energy E and a momentum ρ, which are related to the frequency ν and the wavelength λ of light by the equations E = hv and ρ = h/λ, where h is Planck’s constant. On the other hand, it has been found that a beam of electrons impinging on a crystal gives a diffraction pattern that cannot be interpreted in any other way but on the basis of wave concepts. It was established later that this phenomenon is characteristic of microparticles in general.

Thus, a characteristic feature of the microworld is the duality of corpuscular and wave properties, which cannot be understood within the framework of classical physics. For example, the generation of a diffraction pattern during the scattering of particles is incompatible with the conception of the motion of these particles along trajectories. The wave-particle duality is given a natural interpretation in quantum mechanics.

D. V. GAL’TSOV