Abstract：Energy dissipation is of fundamental interest and crucial importance in quantum systems. However, whether energy dissipation can emerge without backscattering inside topological systems remains a question. As a hallmark, we propose a microscopic picture that illustrates energy dissipation in the quantum Hall (QH) plateau regime of graphene. Despite the quantization of Hall, longitudinal, and two-probe resistances (dubbed as the quantum limit), we find that the energy dissipation emerges in the form of Joule heat. It is demonstrated that non-equilibrium energy distribution of carriers plays much more essential roles than the resistance on energy dissipation. In practice, we also find such energy dissipation phenomenon is universal in topological devices. The mechanism of energy dissipation inspires us to discover principles for designing dissipation-free topological devices. We find that incorporating insulators with both low and high Chern numbers is an essential way for reducing the dissipation in devices. Based on this principle, we have improved the design of various topological devices and eliminated the bulk dissipation.

主讲人简介：

    谢心澄，中国科学院院士，发展中国家科学院院士，美国物理学会会士，北京大学讲席教授/复旦大学理论物理与信息科学交叉中心主任。1982年中国科技大学近代物理系毕业，1988年在美国马里兰大学获博士学位。曾任美国俄克拉荷马州立大学校董事会讲座教授、中科院物理所凝聚态理论与材料计算研究室主任、中科院国际量子结构中心主任、北京大学量子材料科学中心创始主任、北京大学物理学院院长、国家自然科学基金委员会数学物理科学部主任、国家自然科学基金委员会副主任等职。

    谢心澄教授长期从事凝聚态物理理论研究，主要研究方向集中在量子霍尔效应、电荷及自旋输运、低维量子体系等。共发表论文340余篇，包括Nature/Science系列20篇、PRL 50余篇等。曾任两届PRL凝聚态物理副主编，现任《中国科学：物理学 力学 天文学》主编及多项国际重要学术期刊编委。