2021/07/02 by Fabian Glatzel, Tanja Schilling · 5 citations
Biochemistry, Genetics and Molecular Biology · Materials Science · Physics and Astronomy · #Advanced Thermodynamics and Statistical Mechanics #Material Dynamics and Properties #Protein Structure and Dynamics #cond-mat.soft
paper · pdf · doi:10.1209/0295-5075/ac35ba
6 pages, 0 figures
openalex publication_date 2021/07/02 · openalex created_date 2021/11/08 · arxiv created 2022/02/03 · arxiv updated 2022/02/04 · openalex updated_date 2026/08/04
The underdamped, non-linear, generalized Langevin equation is widely used to model coarse-grained dynamics of soft and biological materials. By means of a projection operator formalism, we show under which approximations this equation can be obtained from the Hamiltonian dynamics of the underlying microscopic system and in which cases it makes sense to introduce a potential of mean force. We discuss shortcomings of previous derivations presented in the literature and demonstrate the implications of our derivation for the structure of memory terms and their connection to generalized fluctuation-dissipation relations. We show, in particular, that the widely used, simple structure which contains a potential of mean force, a memory term which is linear in the observable, and a fluctuating force which is related to the memory term by a fluctuation-dissipation relation, is neither exact nor can it, in general, be derived as a controlled approximation to the exact dynamics.