Unusual slow energy relaxation induced by mobile discrete breathers in onedimensional lattices with next-nearestneighbor coupling  

作　　者：Bin Xu Jun Zhang Wei Zhong Chi Xiong Daxing Xiong 

机构地区：[1]Department of Physics,Fuzhou University,Fuzhou 350108,China [2]MinJiang Collaborative Center for Theoretical Physics,College of Physics and Electronic Information Engineering,Minjiang University,Fuzhou 350108,China

出　　处：《Communications in Theoretical Physics》2022年第6期152-158,共7页理论物理通讯（英文版）

基　　金：supported by the start-up fund of Minjiang university and NSF (Grant No. 2021J02051) of Fujian Province of China;supported by the start-up fund of Minjiang University;supported by the NNSF (Grant No. 12105133) of China;NSF (Grant No. 2021J011030) of Fujian Province of China。

摘　　要：We study the energy relaxation process in one-dimensional(1D) lattices with next-nearestneighbor(NNN) couplings. This relaxation is produced by adding damping(absorbing conditions) to the boundary(free-end) of the lattice. Compared to the 1D lattices with on-site potentials, the properties of discrete breathers(DBs) that are spatially localized intrinsic modes are quite unusual with the NNN couplings included, i.e. these DBs are mobile, and thus they can interact with both the phonons and the boundaries of the lattice. For the interparticle interactions of harmonic and Fermi-Pasta-Ulam-Tsingou-β(FPUT-β) types, we find two crossovers of relaxation in general, i.e. a first crossover from the stretched-exponential to the regular exponential relaxation occurring in a short timescale, and a further crossover from the exponential to the power-law relaxation taking place in a long timescale. The first and second relaxations are universal, but the final power-law relaxation is strongly influenced by the properties of DBs, e.g. the scattering processes of DBs with phonons and boundaries in the FPUT-β type systems make the power-law decay relatively faster than that in the counterparts of the harmonic type systems under the same coupling. Our results present new information and insights for understanding the slow energy relaxation in cooling the lattices.

关 键 词：energy relaxation discrete breathers next-nearest-neighbor coupling 

分 类 号：O411[理学—理论物理]