Home >  研究会等 > Magnetization plateaus of two-dimensional geometrically frustrated quantum spin systems from the one-dimensional perspective.

Magnetization plateaus of two-dimensional geometrically frustrated quantum spin systems from the one-dimensional perspective.

日程 : 2021年2月17日(水) 4:00 pm - 5:00 pm 場所 : On Zoom (Please make a registration through the link below) 講師 : Dr. Shunsuke C. Furuya 所属 : Ibaraki University 世話人 : 押川 正毅 (ex. 63451)
e-mail: oshikawa@issp.u-tokyo.ac.jp

The Lieb-Schultz-Mattis theorem has recently drawn a renewed interest from theoretical physicists for its close connection to anomalies of quantum field theories. The U(1) flux-insertion argument is advantageous to discuss the Lieb-Schultz-Mattis theorem. It provides a simple method to investigate the Lieb-Schultz-Mattis theorem in quantum spin systems on magnetization plateaus, the well-known Oshikawa-Yamanaka-Affleck condition.In this presentation, we first discuss an inspiring example of the flux insertion argument in quantum spin systems on the checkerboard lattice. The simple flux insertion argument with the periodic or the tilted boundary condition fails to forbid the unique gapped ground state. This failure originates from the fact that we need to impose an extra symmetry to exclude the possibility of the unique gapped ground state from the checkerboard-lattice quantum spin systems. We show how to incorporate the extra symmetry and the flux insertion argument.Next, we move on to kagome-lattice antiferromagnets. We give our attention to the 1/3 magnetization plateau of kagome antiferromagnets, where the Oshikawa-Yamanaka-Affleck condition admits the unique gapped ground state. We discuss the 1/3 magnetization plateau of a spin-1/2 three-leg spin tube based on an anomaly of SU(3) Wess-Zumino-Witten theory and relate it to the 1/3 plateau of the kagome antiferromagnet. 

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(公開日: 2021年02月12日)