论文标题
Fermi-Pasta-Ulam链的热运输特性正在经历软球类型碰撞
Thermal transport characteristics of Fermi-Pasta-Ulam chains undergoing soft-sphere type collisions
论文作者
论文摘要
我们从数字上表明，在著名的Fermi-Pasta-Ulam（$ fpu $）链中包括软球型碰撞完全改变了热运输特性。由此产生的$ fpu^c $链，在保持动力的同时，满足了傅立叶定律，并且没有显示出异常的热运输行为。碰撞在减少$ fpu $链中通常观察到的边界跳跃方面起着重要作用。 $ fpu^c $链的导热率明显小于低温下的$ fpu $链，这是由于能量从最低振动模式的快速重新分布到较高的模式。然而，在高温下，由于对热通量的贡献很大，因此$ fpu^c $链具有比$ fpu $链的导热率更大的导热率。
We show numerically that including soft-sphere type collisions in the celebrated Fermi-Pasta-Ulam ($FPU$) chain completely alters the thermal transport characteristics. The resulting $FPU^C$ chains, while being momentum preserving, satisfy the Fourier's law and do not show anomalous thermal transport behavior. Collisions play a significant role in reducing the boundary jumps typically observed in $FPU$ chains. The thermal conductivity of the $FPU^C$ chains is significantly smaller than the $FPU$ chains at low temperatures due to the fast redistribution of energy from the lowest mode of vibrations to the higher modes. At high temperatures, however, the $FPU^C$ chains have larger thermal conductivity than the $FPU$ chains due to the large contributions to the heat flux because of the large-magnitude short-ranged anharmonic collision force.
