Quantum responses of topological superconductors

2022 Fiscal Year Final Research Report

• Project/Area Number: 20H00131
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Medium-sized Section 13:Condensed matter physics and related fields
• Research Institution: Kyoto University
• Principal Investigator: SATO Masatoshi 京都大学, 基礎物理学研究所, 教授 (30313117)
• Co-Investigator(Kenkyū-buntansha): 田仲 由喜夫 名古屋大学, 工学研究科, 教授 (40212039) ; 柏谷 聡 名古屋大学, 工学研究科, 教授 (40356770)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: トポロジカル相 / トポロジカル超伝導

Outline of Final Research Achievements

We have developed a systematic method to obtain the electromagnetic response of Majorana fermions in topological superconductors. In particular, using the K-theory classification of topological superconductors and the representation theory of Majorana fermions with respect to crystal symmetry, we succeeded in developing a theory that relates the symmetry of the Cooper pairing to the magnetic response of Majorana fermions. We also developed a theory for superconductor junctions, which play an important role in detecting topological superconductivity. Furthermore, we obtained experimental results that support the idea that CaAgP is a new topological superconductor. In addition, we have also performed a fundamental study of the non-Hermitian topological phase, which is important for incorporating dissipation effects into topological superconductors.

Free Research Field

物性理論および場の量子論

Academic Significance and Societal Importance of the Research Achievements

超伝導現象は基本的な物理現象であり、応用上も重要であるが、その元となるクーパー対の対称性をきめることは非常に難しく、多くの異方的超伝導体では未だクーパー対の対称性は決まっていない。本研究は、異方的超伝導体が持つ特徴的な励起であるマヨラナフェルミオンに着目し、その電磁応答を調べることで、クーパー対の対称性を決定することが可能であることを示しており、応用上も重要な現象である超伝導研究に新しい方向性を与えるものである。