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出典:『Wikipedia』 (2011/06/11 18:57 UTC 版)

英語による解説

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In physics, quasiparticles (and related collective excitations) are emergent phenomena that occur when a microscopically-complicated system such as a solid behaves as if it contained different (fictitious) weakly-interacting particles in free space. For example, as an electron travels through a semiconductor, its motion is disturbed in a complex way by its interactions with all of the other electrons and nuclei; however it approximately behaves like an electron with a different mass traveling unperturbed through free space. This "electron" with a different mass is called an "electron quasiparticle". In an even more surprising example, the aggregate motion of electrons in the valence band of a semiconductor is the same as if the semiconductor contained instead positively-charged quasiparticles called holes. Other quasiparticles or collective excitations include phonons (particles derived from the vibrations of atoms in a solid), plasmons (particles derived from plasma oscillations), and many others.