论文标题
通过单个免费电子对离散量子系统的完全激发
Complete Excitation of Discrete Quantum Systems by Single Free Electrons
论文作者
论文摘要
我们揭示了各个低能电子和包含离散数量状态的样品之间相互作用的非线性和后坐力效应。通过对组合的自由电子和两级系统的量子理论描述，我们发现最大可实现的激发概率为$ 100 \％$，这需要与耦合强度和过渡对称性有关的特定条件，正如我们通过对偶性和四极性模式的计算来说明的。当探针的动能位于过渡阈值附近时，也会观察到强逆转效应，尽管即使与任意复杂的多级样品的非线性相互作用充分考虑了非线性相互作用，但相关的概率仍然独立于电子波函数。我们的工作揭示了自由电子控制局部激发并描述这种控制的边界的潜力。
We reveal a wealth of nonlinear and recoil effects in the interaction between individual low-energy electrons and samples comprising a discrete number of states. Adopting a quantum theoretical description of combined free-electron and two-level systems, we find a maximum achievable excitation probability of $100\%$, which requires specific conditions relating to the coupling strength and the transition symmetry, as we illustrate through calculations for dipolar and quadrupolar modes. Strong recoil effects are observed when the kinetic energy of the probe lies close to the transition threshold, although the associated probability remains independent of the electron wave function even when fully accounting for nonlinear interactions with arbitrarily complex multilevel samples. Our work reveals the potential of free electrons to control localized excitations and delineates the boundaries of such control.
