We explain the vibrations of a Frenkel–Kontorova (FK) model under Shapiro steps by the action of an external alternating force. We demonstrate Shapiro steps for a case with soft ‘springs’ between an 8-particles FK chain. Shapiro steps start with a single jump over the highest \(\hbox {SP}_4\) in the global valley through the PES. They finish with doubled, and again doubled oscillations. We study in this part I a traditional FK model with periodic boundary conditions.

中文翻译：

---

Shapiro在Frenkel–Kontorova模型的势能面上的台阶描述第一部分：可变框中的链

我们通过外部交变力的作用解释了夏皮罗步骤下的Frenkel-Kontorova（FK）模型的振动。我们演示了在8粒子FK链之间带有软“弹簧”的情况下的Shapiro步骤。Shapiro的步骤从通过PES跳过全球山谷中最高的\（\ hbox {SP} _4 \）开始。它们以两倍的振动结束，并再次以两倍的振动振动。我们在这一部分中研究带有周期边界条件的传统FK模型。