论文标题
晶格中的相干等离子体
Coherent Plasma in a Lattice
论文作者
论文摘要
我们提出了一个完全第二定量的计算，显示电磁场自发相干构型在与常规晶格中与带电的玻色子相互作用时的出现。玻色子倾向于以等离子频率振荡，但也受到静电力的影响，使其限制在晶格位点附近并导致振荡的频移。在这些频率的某些条件下，我们发现一组适当定义的相干状态（在野外和物质的自由度中连贯）表现出相对于扰动基态的负能量差距。在RWA近似和与位置无关的磁场中，在相互作用的哈密顿式相互作用中都是如此。我们将此结果与腔Qed的其他最新发现进行了比较，并注意到：（1）考虑完整的3D波函数和对相干状态的仔细定义对于获得能量差距至关重要； （2）尽管我们的计算是指玻色子，但如果与可用状态的密度相比，它们的密度非常低，也可能适用于以晶体基质结合的质子。
We present a fully second-quantized calculation showing the emergence of spontaneous coherent configurations of the electromagnetic field in interaction with charged bosons in a regular lattice. The bosons tend to oscillate at their plasma frequency, but are also subjected to electrostatic forces which keep them confined close to lattice sites and cause a frequency shift in the oscillation. Under certain conditions on these frequencies, we find that a suitably defined set of coherent states (coherent both in the field and matter degrees of freedom) exhibit a negative energy gap with respect to the perturbative ground state. This is true in the RWA approximation and for position-independent fields, both to first and second order in the interaction Hamiltonian. We compare this result with other recent findings from cavity QED and notice that: (1) consideration of full 3D wavefunctions and a careful definition of the coherent states are essential for obtaining the energy gap; (2) although our calculation is referred to bosons, it may also apply to protons bound in a crystal matrix, if their density is very low compared to the density of available states.
