Regensburg 2016 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 15: Focus Session: Spectroscopy of Quantum Spin Liquids

TT 15.3: Invited Talk

Monday, March 7, 2016, 16:00–16:30, H20

Kagome chiral spin liquid and symmetry protected topological phases — •Yin-Chen He — Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Straße 38, 01187, Dresden, Germany

In my talk I will introduce the chiral spin liquid phase that occurs in kagome antiferromagnets and discuss its physical origin as a gauged U(1) SPT phase. I will first present our numerical (DMRG) study on the kagome XXZ spin model that exhibits two distinct spin liquid phases, namely the chiral spin liquid and the kagome spin liquid (the groundstate of the nearest neighbor kagome Heisenberg model). Both phases extend from the extreme easy-axis limit, through SU(2) symmetric point, to the pure easy-plane limit. The two phases are separated by a continuous phase transition. Motivated by these numerical results, I will then focus on the easy-axis kagome spin system, and reformulate it as a lattice gauge model. Such formulation enables us to achieve a controlled theoretical description for the spin liquid phase. We then show that the chiral spin liquid is indeed a gauged U(1) symmetry protected topological (SPT) phase.

[1] Yin-Chen He, S. Bhattacharjee, F. Pollmann, and R. Moessner,

arXiv:1509.03070

[2] Yin-Chen He, S. Bhattacharjee, R. Moessner, and Frank Pollmann,

PRL 115, 116803 (2015)

[3] Yin-Chen He and Yan Chen, PRL 114, 037201 (2015).

[4] Yin-Chen He, D. N. Sheng and Y. Chen, PRL 112, 137202 (2014).