title: Markov state modeling of sliding friction.
abstract: Markov state modeling (MSM) has recently emerged as one of the key techniques for the discovery of collective variables and the analysis of rare events in molecular simulations. In particular in biochemistry this approach is successfully exploited to find the metastable states of complex systems and their evolution in thermal equilibrium, including rare events, such as a protein undergoing folding. The physics of sliding friction and its atomistic simulations under external forces constitute a nonequilibrium field where relevant variables are in principle unknown and where a proper theory describing violent and rare events such as stick slip is still lacking. Here we show that MSM can be extended to the study of nonequilibrium phenomena and in particular friction. The approach is benchmarked on the Frenkel-Kontorova model, used here as a test system whose properties are well established. We demonstrate that the method allows the least prejudiced identification of a minimal basis of natural microscopic variables necessary for the description of the forced dynamics of sliding, through their probabilistic evolution. The steps necessary for the application to realistic frictional systems are highlighted.
authors.affiliation: SISSA, Via Bonomea 265, I-34136 Trieste, Italy.|CNR-IOM Democritos National Simulation Center, Via Bonomea 265, I-34136 Trieste, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Pellegrini
authors.affiliation: International Centre for Theoretical Physics (ICTP), Strada Costiera 11, I-34151 Trieste, Italy.
authors.forename: François P
authors.initials: FP
authors.lastname: Landes
authors.affiliation: SISSA, Via Bonomea 265, I-34136 Trieste, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Laio
authors.affiliation: Università degli Studi di Messina, Dipartimento di Scienze Matematiche ed Informatiche, Scienze Fisiche e Scienze della Terra, Contrada Papardo, I-98166 Messina, Italy.|CNR-IPCF, Viale F. Stagno d'Alcontres 37, I-98158 Messina, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Prestipino
authors.affiliation: SISSA, Via Bonomea 265, I-34136 Trieste, Italy.|CNR-IOM Democritos National Simulation Center, Via Bonomea 265, I-34136 Trieste, Italy.|International Centre for Theoretical Physics (ICTP), Strada Costiera 11, I-34151 Trieste, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Tosatti