论文标题

各向异性量子磁铁中稳定的希格斯模式

Stable Higgs mode in anisotropic quantum magnets

论文作者

Su, Ying, Masaki-Kato, A., Zhu, Wei, Zhu, Jian-Xin, Kamiya, Yoshitomo, Lin, Shi-Zeng

论文摘要

与凝结物质系统中订单参数的振幅波动相关的低能激发可以模仿标准模型中的基本粒子Higgs Boson,并将其称为Higgs模式。识别凝结的希格斯模式是具有挑战性的,因为在许多情况下,它迅速衰减到其他低能玻色粒模式中,这使HIGGS模式不可见。因此,希望找到一种稳定HigGS模式的方法,该模式可以深入了解Higgs模式在冷凝物理学中的稳定机制。在量子磁铁中,由自发对称性破裂引起的磁序支持横向(镁)和纵向(希格斯模式)波动。当连续的对称性破裂时,金石镁模式通常具有比希格斯模式低的激发能,从而导致后者的快速衰变。在这项工作中,我们表明,稳定的希格斯模式存在于各向异性量子磁体中,附近二聚体和磁相之间的量子临界点。我们发现,易于轴各向异性会增加镁质差距,使得镁模式在量子临界点附近的Higgs模式上方,并且HIGGS模式的衰减被禁止运动。我们的结果表明,各向异性量子磁铁提供了理想的平台,以探索凝结物质系统中的希格斯物理。

Low-energy excitations associated with the amplitude fluctuation of an order parameter in condensed matter systems can mimic the Higgs boson, an elementary particle in the standard model, and are dubbed as Higgs modes. Identifying the condensed-matter Higgs mode is challenging because it is known in many cases to decay rapidly into other low-energy bosonic modes, which renders the Higgs mode invisible. Therefore, it is desirable to find a way to stabilize the Higgs mode, which can offer an insight into the stabilization mechanism of the Higgs mode in condensed matter physics. In quantum magnets, magnetic order caused by spontaneous symmetry breaking supports transverse (magnons) and longitudinal (Higgs modes) fluctuations. When a continuous symmetry is broken, the Goldstone magnon mode generally has a lower excitation energy than the Higgs mode, causing a rapid decay of the latter. In this work, we show that a stable Higgs mode exists in anisotropic quantum magnets near the quantum critical point between the dimerized and magnetically ordered phases. We find that an easy axis anisotropy increases the magnon gap such that the magnon mode is above the Higgs mode near the quantum critical point, and the decay of the Higgs mode into the magnon mode is forbidden kinematically. Our results suggest that the anisotropic quantum magnets provide ideal platforms to explore the Higgs physics in condensed matter systems.

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