## 1993 pARSHIN - REVIEW [Soft potential model and universal properties of glasses](https://knowen-production.s3.amazonaws.com/uploads/attachment/file/5484/parshin%2Breview.pdf)


## [Vibrational instability, two-level systems, and the boson peak in glasses](https://core.ac.uk/download/pdf/34939243.pdf)
D. A. Parshin

> In summary, we have shown that **the same physical mechanism is fundamental for such seemingly different phenomena** as the formation of the two-level systems in glasses and the boson peak in the reduced density of low-frequency
> vibrational states. In this way, **two of the most fundamental properties of glasses are interconnected

> In our theory, it follows naturally. The physical reason for the small value of the parameter C is that only a small fraction of all created TLS’s can actually tunnel in realistic time scales.

- https://arxiv.org/pdf/0711.0461.pdf

https://arxiv.org/pdf/cond-mat/0203165.pdf