# localized but collective LEEs - P

## LEEs - low-energy excitations - more general name than TLSs

- collective and universal

**therefore quantum statistics!**
[collective game is qualitatively different from original individual game - microscopic origin is UNimportant if excitations are collective](https://www.empirical.net/wp-content/uploads/2012/06/the_losers_game.pdf)⏎

- but localized

therefore different from delocalized critical modes around phase transitions

- QLTG - quantum low-temperature glasses

SNS is strongly noncrystalline solid

## the definition of the consonance between glassons-fermions and phonons-bosons



phonon ($c_s$) parameters, fermion parameters ($m_{gl}$, Fermi velocity $v_F$, etc.), and their coupling $\lambda_{gl-ph}$ are self-consistent.
This structural consistency leads to universality of dimensionless sound friction $Q^{-1}$

## [Anderson localization](https://knowen.org/nodes/999) of fermions-glassons required by experimental data, therefore Fermi glass

## Fermions-glassons

- podcast [What are quasi-particles - Daniel and Jorge Explain the Universe](https://podcasts.apple.com/gb/podcast/daniel-and-jorge-explain-the-universe/id1436616330?i=1000485574032)

-  https://www.championingscience.com/2019/03/15/everything-should-be-made-as-simple-as-possible-but-no-simpler/

# Parents

* FERMI GLASS - P
* multiple theories of low-T universalities - Burin, Yu, etc.
* Universal properties of glasses - BOOKs