物理学院“博约学术论坛”系列报告第 146 期(2018年第 8期)

题目：Topological Majorana Two-Channel Kondo Effect
报告人：鲍志强 博士（美国德克萨斯大学达拉斯分校物理系） 
时  间：2018年4月12日(周四)上午10:00
地  点：华体会体育中心教学楼610
摘要：

The Kondo effect is one of the most fundamental problems in condensed matter physics. Not only does it reveal how delocalized electrons interact with a local degeneracy, but it also exemplifies scaling and universality in strongly correlated systems that are driven by weak coupling instabilities. In the 1 channel Kondo (1CK) effect, a twofold degeneracy such as a local spin-1/2 impurity is antiferromagnetically coupled to a reservoir of conduction electrons and the ground state is a Fermi liquid. In the more tantalizing 2CK effect, two independent reservoirs compete to screen the spin and thus overscreen it, leading to non-Fermi-liquid quantum criticality. The delicate 2CK effect is unlikely to occur, as any channel asymmetry drives the system toward the 1CK effect in the more strongly coupled channel. Realizing the 2CK effect without fine-tuning the channel symmetry has long been an unrealized dream. In this work, we propose a new device named Majorana transistor, which is a time-reversal-invariant topological superconductor (TSC) grounded by a capacitor and tunnel-coupled to left and right leads. By using the standard Schrieffer-Wolf transformation and perturbative renormalization group method, we demonstrate the realization of a topologically protected, channel-symmetric, two-channel Kondo effect without fine-tuning in the Majorana transistor. We also examine the transport anomaly of the Majorana transistor. Whereas the nonlocal teleportation vanishes, a lead present at one end telecontrols the universal transport through the other end.

简历：
鲍志强博士，目前在美国德克萨斯大学达拉斯分校物理系做博士后，主要研究方向包括量子多体与Kondo效应，凝聚态物理中的新奇量子现象，量子输运等。2015年博士毕业于中国科学院物理研究所，2012年硕士毕业于北京大学物理学院，2008年本科毕业于天津大学。

联系方式：物理学院办公室 （15810823175）
邀请人：刘铖铖
网    址：http://physics.bit.edu.cn/