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Concept
Matter wave
Résumé
Matter waves are a central part of the theory of quantum mechanics, being half of wave–particle duality. All matter exhibits wave-like behavior. For example, a beam of electrons can be diffracted just like a beam of light or a water wave.
The concept that matter behaves like a wave was proposed by French physicist Louis de Broglie (dəˈbrɔɪ) in 1924, and so matter waves are also known as de Broglie waves.
The de Broglie wavelength is the wavelength, λ, associated with a particle with momentum p through the Planck constant, h:
Wave-like behavior of matter was first experimentally demonstrated by George Paget Thomson and Alexander Reid's transmission diffraction experiment, and independently in the Davisson–Germer experiment, both using electrons; and it has also been confirmed for other elementary particles, neutral atoms and molecules.
At the end of the 19th century, light was thought to consist of waves of electromagnetic fields which propagated according to Maxwell's equations, while matter was thought to consist of localized particles (see history of wave and particle duality). In 1900, this division was questioned when, investigating the theory of black-body radiation, Max Planck proposed that the thermal energy of oscillating atoms is divided into discrete portions, or quanta. Extending Planck's investigation in several ways, including its connection with the photoelectric effect, Albert Einstein proposed in 1905 that light is also propagated and absorbed in quanta, now called photons. These quanta would have an energy given by the Planck–Einstein relation:
and a momentum vector
where ν (lowercase Greek letter nu) and λ (lowercase Greek letter lambda) denote the frequency and wavelength of the light, c the speed of light, and h the Planck constant. In the modern convention, frequency is symbolized by f as is done in the rest of this article.
Source officielle
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