论文标题
纵向模式的衰减和重新归一化
Decay and renormalization of a longitudinal mode in a quasi-two-dimensional antiferromagnet
论文作者
论文摘要
量子材料研究中的一个持续挑战是揭示和解释自旋系统中的集体量子效应，在不同模式类型之间的相互作用很重要。在这里，我们通过在易于平面量子磁铁中的相互作用和纵向模式的相互作用和纵向模式的相互作用和理论研究来解决这个问题。我们的无弹性中子散射测量值BA $ _ {2} $ FESI $ _ {2} o $ $ _ {7} $揭示了整个Brillouin区域的纵向模式的出现，衰减和重归化。纵向模式的衰减在区域中心特别明显。为了说明各向异性磁体中相互作用的低能模式的多体效应，我们概括了标准的自旋波理论。通过包括所有一环校正来重现测得的模式衰减和重新归一化。这里开发的理论框架广泛适用于具有多种低能模式的量子磁铁。
An ongoing challenge in the study of quantum materials, is to reveal and explain collective quantum effects in spin systems where interactions between different modes types are important. Here we approach this problem through a combined experimental and theoretical study of interacting transverse and longitudinal modes in an easy-plane quantum magnet near a continuous quantum phase transition. Our inelastic neutron scattering measurements of Ba$_{2}$FeSi$_{2}O$_{7}$ reveal the emergence, decay, and renormalization of a longitudinal mode throughout the Brillouin zone. The decay of the longitudinal mode is particularly pronounced at the zone center. To account for the many-body effects of the interacting low-energy modes in anisotropic magnets, we generalize the standard spin-wave theory. The measured mode decay and renormalization is reproduced by including all one-loop corrections. The theoretical framework developed here is broadly applicable to quantum magnets with more than one type of low energy mode.
