What is the particle nature of matter

Big Bang 7, textbook

Waves and Particles 33 RG 7.2 G 7.2 Competence Area Quantum Physics 59 33.4 Soccer Quanta Matter Waves So there was evidence for both the wave and the particle nature of light. That was an unbelievable shock because, according to the view at the time, it couldn't be. But this dual nature is not only evident in photons, but also in other small particles. It was now proven that light has both wave and particle properties. In 1924, the French physicist L OUIS D E B ROGLIE (pronounced “de Broi”) put forward a daring hypothesis. Why should this double nature only apply to photons and not to other quanta as well? Why, for example, should electrons not also have wave properties in addition to their particle properties, in other words also be a matter wave? De Broglie established a connection between particle momentum and wavelength (Tab. 33.2; see also F31, p. 65). With an electron microscope, images can be taken with astonishing magnification and quality (Fig. 33.19). But how can you actually take pictures with the help of electrons? How does the distance between the bright stripes change in a diffraction experiment with the wavelength used? Look in Fig. 33.12, p. 56! Why do you build ever larger particle accelerators to study quanta? L F15 W1 Fig. 33.19: Above: snow crystals; below: house dust mite; Both photos are colored. F16 W1 F17 E1 Formula: Matter wavelength (de Broglie wavelength) λ = h __ p = h ___ mv λ… wavelength of the matter waves [m] p… momentum [kgms –1] m… mass [kg] v… speed of the particle [ ms –1] h… Planck's quantum of action [Js] wavelength in m red photon 10 –6 UV-B photon 10 –7 X-ray photon (hard radiation) 10 –11 electron, 10 8 m / s (30 keV) 10 –11 “Soccer molecules” (C60), 220m / s 10 –12 tennis ball, 30m / s 10 –34 people with 75 kg at 10m / s 10 –36 Tab. 33.2: Examples of magnitude values ​​for wavelengths in light and matter: also macroscopic Objects, such as a tennis ball, can therefore be assigned a wavelength. But this is so absurdly tiny that its wave properties are not noticeable in everyday life. That sounded pretty crazy. In fact, the wave properties of electrons and the correctness of the equation for matter waves could already be proven in 1927. To date, the dual nature of quanta has also been proven for neutrons, atoms and even for giant molecules. De Broglie's apparently absurd assumption turned out to be absolutely correct and was an important step in the direction of today's quantum mechanics. Info: Football quanta -> p. 60 Info: Electron microscope -> p. 60 In principle, the de Broglie equation allows a wavelength to be assigned to each object (Tab. 33.2). Since the wavelength decreases with increasing mass, the interference fringes move together (F16). This is why it becomes more and more difficult to prove this, the larger the objects become. So where is the limit for observing quantum interference? A NTON Z EILINGER, Austrian quantum physicist of global stature, says: “The answer to this question will probably be left to the ingenuity of the experimenter rather than fundamental theoretical considerations”. But it will probably never be possible for macroscopic objects because their wavelength is so absurdly tiny. F For testing purposes only - property of the publisher öbv

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