Information AboutQuasiparticle |
| CATEGORIES ABOUT QUASIPARTICLE | |
| fundamental physics concepts | |
| condensed matter physics | |
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In the language of many-body Quantum Mechanics , a quasiparticle is a type of low-lying Excited State of the system (a state possessing energy very close to the Ground State energy) that is known as an Elementary Excitation . This means that most of the other low-lying excited states can be viewed as states in which multiple quasiparticles are present. It turns out that the interactions between quasiparticles become negligible at sufficiently low Temperature s, in which case we can obtain a great deal of information about the system as a whole, including the Flow Properties and Heat Capacity , by investigating the properties of individual quasiparticles. Actually, most many-body systems possess two types of elementary excitations. The first type, the quasiparticles, correspond to ''single'' particles whose motions are modified by interactions with the other particles in the system. The second type of excitation corresponds to a collective motion of the system as a whole. These excitations are called Collective Mode s, and they include phenomena such as Zero Sound , Plasmon s, and Spin Density Wave s. The idea of quasiparticles originated in Landau's theory of Fermi Liquid s, which was originally invented for studying liquid Helium-3 This is similar to Dressed Particle s in quantum field theory. REFERENCES
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