论文标题
在二维量子抗fiferromagnet的Lifshitz自旋液相中巨大的准粒子辐射
Colossal quasiparticle radiation in the Lifshitz spin liquid phase of a two-dimensional quantum antiferromagnet
论文作者
论文摘要
磁系统中的强量子波动可以产生物质的无序量子自旋液相，而经典物理学预测的物质则不会预测。在自旋液体中展示的外来现象的复杂性导致了很多理论和实验意义。但是，了解这些系统中激发的基本性质仍然具有挑战性。在这项工作中，我们考虑了二维沮丧的$ xy $ antiferromagnet中的lifshitz量子关键点。此时，量子波动破坏了远距离顺序，导致代数Lifshitz自旋液体的形成。我们证明，在Lifshitz旋转液相中，玻色粒镁激发是长寿的，并且在液相中明确定义，尽管矛盾的是，动态结构因子具有广泛的非Lorentzian频率分布，没有单粒子的重量。我们通过表明Lifshitz自旋液体遭受红外灾难来解决这一明显的矛盾：外部物理探针总是会激发无限数量的任意低能量准粒子，从而导致光谱的显着辐射扩展。
Strong quantum fluctuations in magnetic systems can create disordered quantum spin liquid phases of matter which are not predicted by classical physics. The complexity of the exotic phenomena on display in spin liquids has led to a great deal of theoretical and experimental interest. However, understanding the fundamental nature of the excitations in these systems remains challenging. In this work, we consider the Lifshitz quantum critical point in a two-dimensional frustrated $XY$ antiferromagnet. At this point, quantum fluctuations destroy long range order, leading to the formation of an algebraic Lifshitz spin liquid. We demonstrate that the bosonic magnon excitations are long-lived and well-defined in the Lifshitz spin liquid phase, though paradoxically, the dynamic structure factor has a broad non-Lorentzian frequency distribution with no single-particle weight. We resolve this apparent contradiction by showing that the Lifshitz spin liquid suffers from an infrared catastrophe: An external physical probe always excites an infinite number of arbitrarily low energy quasiparticles, which leads to significant radiative broadening of the spectrum.
