Isothermal Heat Conduction In Nonlinear Lattices

Nonlinear lattice is one of the important materials to collect wasteful thermal energy and prepare thermal devices,its thermal properties have become a hot research area of physics and materials science.By means of theory analysis and numerical calculations,isothermal conduction phenomena in the FK and FPU-?lattice are investigated.The numerical calculation results will not only provide important reference value and practical significance in control of thermal energy and preparation of thermal devices.The paper consists of the followingparts.Firstly,the isothermal conduction phenomena in the FK lattice is investigat-ed for two different cases,one is with the external period signal and the other is without the external period signal.The results show that as the signal and the nosie achieve a coordination with each other,the system occurs isothermal con-duction phenomena,i.e.,the system still emerges the thermal current even without thermal difference.While the isothermal conduction phenomena and magnitude of thermal current are determined by some dynamical parameters of the system,such as lattice period,intensity of the noise,amplitude of on-site potential and the external period signal,etc.In the case of no external period signal,there still exists the isothermal conduction phenomena in theof FK lattice with the inter-play of lattice period and on-site potential,and the value of thermal current is determined by lattice period and the amplitude of on-site potential.Secondly,the isothermal conduction phenomena in the FPU-? lattice is stud-ied.The results indicate:adjustment of the external period signal to the thermal bath or action of the external period signal in the end of the system,there still occurs the isothermal conduction phenomenon in the FPU-? lattice.In addition,similar to FK lattice,there exists a certain value of the driving frequency and the corresponding noise intensity at which the thermal current takes its maxi-mum.While as the noise intensity is bigger or smaller than the value,the thermal current will decrease obviously.