Department of Physics, Tokyo Institute of Technology, 2-12-1, O-okayama, Meguro-ku, Tokyo 152-8551, Japan.
J Phys Condens Matter. 2012 Aug 29;24(34):343201. doi: 10.1088/0953-8984/24/34/343201. Epub 2012 Aug 7.
Superfluid (3)He is an intensively investigated and well characterized p-wave superfluid. In the bulk Balian-Werthamer state, which is commonly called the (3)He B phase, the superfluid gap is opened isotropically but near a flat boundary such as a wall of a container it can harbor interesting quasi-particle states inside the gap. These states are called surface Andreev bound states, and have not been experimentally explored in detail. Transverse acoustic impedance measurement has revealed their existence and provided spectroscopic details of the dispersion of the bound states. Recent theoretical arguments claim that the surface Andreev bound states of the superfluid (3)He B phase can be recognized as the edge states of the topological superfluid and be regarded as a Majorana fermion, a fancy particle which has not been confirmed in elementary particle physics. In this review, we present up-to-date knowledge on the surface Andreev bound states of the (3)He B phase revealed by acoustic spectroscopy and the possible realization of a Majorana fermion, along with related studies on this topic.
超流 3He 是一种经过深入研究且具有良好特性的 p 波超流体。在体的 Balian-Werthamer 态，通常称为 3He B 相，超流能隙在各向同性地打开，但在诸如容器壁等平坦边界附近，它可以在能隙内容纳有趣的准粒子态。这些态称为表面安德烈夫束缚态，尚未在实验中详细探索。横向声阻抗测量揭示了它们的存在，并提供了束缚态色散的光谱细节。最近的理论论点声称，超流 3He B 相的表面安德烈夫束缚态可以被识别为拓扑超流的边缘态，并被视为马约拉纳费米子，这是一种在基本粒子物理学中尚未被证实的奇特粒子。在这篇综述中，我们介绍了由声学光谱揭示的 3He B 相表面安德烈夫束缚态的最新知识，以及马约拉纳费米子的可能实现，以及相关的研究。
