다체계이론연구실과 고체전자구조계산연구실에서 University of Maryland의 김준현 박사님을 초청하여 아래와 같이 세미나를 개최합니다.

학과 구성원 여러분의 많은 참석을 부탁 드립니다.

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○ Date/time: 2019. 05. 16(Thu.) 14:00

○ Place: 기초과학연구소 세미나실(31317호)

○ Speaker: 김  준  현  박사님 (University of Maryland)

○ Title: The Chiral anomaly without Landau levels

○ Abstract:  We study the chiral anomaly in disordered Weyl semimetals, where the broken translational symmetry prevents the direct application of Nielsen and Ninomiya’s mechanism. In the weak disorder regime, there exists rare regions of the random potential where the disorder strength is locally strong, which gives rise to quasi-localized resonances and their effect on the chiral anomaly is unknown. We numerically show that these resonant states do not affect the chiral anomaly only in the case of a single Weyl node. At energies away from the Weyl point, or with strong disorder where one is deep in the diffusive regime, the chiral Landau level itself is not well defined and the semiclassical treatment is not justified. In this limit, we analytically use the supersymmetry method and find that the Chern-Simons term in the effective action which is not present in non-topological systems gives rise to a non-zero average level velocity which implies chiral charge pumping. We numerically establish that the non-zero average level velocity serves as an indicator of the chiral anomaly in the diffusive limit.