Elementary excitations VS. Quasiparticles

[timspac]

"Elementary excitations" VS. "Quasiparticles"

What's the difference between "Elementary exitations" and "Quasiparticle"?

Thanks!

 

[Bob_for_short]

What's the difference between "Elementary exitations" and "Quasiparticle"?

They are essentially the same things.

A quasi-particle is an entity to obey a particle-like equation. For example, the center of inertia R and the relative distance r between two particles obey particle-like equations but with non-particle masses: M_tot and µ (=m_reduced).

Elementary excitations are also simple "particle-like" entities used to describe the internal degrees of freedom (like r).

 

[charng]

The terms "elementary excitations" and "quasiparticles" are often used interchangeably, but there are some subtle differences between them. Elementary excitations refer to the fundamental particles or excitations that make up a system, such as electrons, photons, or phonons. These are the fundamental building blocks of a system and can be described by well-established physical laws.

On the other hand, quasiparticles refer to excitations in a system that behave like particles, but are actually collective excitations of the underlying elementary particles. These can arise due to interactions between the elementary particles and can have different properties than the individual particles themselves. Examples of quasiparticles include phonons, plasmons, and magnons.

In summary, the main difference between elementary excitations and quasiparticles is that the former are the fundamental building blocks of a system, while the latter are collective excitations that emerge from interactions between these elementary particles. Both concepts are important in understanding the behavior of complex systems and have significant applications in various fields of science and technology.