Approaching Frustrated Magnetism with Symmetric PEPS (Ji-Yao Chen)

  • Date: Sep 18, 2018
  • Time: 11:30 AM - 12:30 PM (Local Time Germany)
  • Speaker: Dr. Ji-Yao Chen, Laboratoire de Physique Théorique, Université de Toulouse III Paul Sabatier
  • Room: New Lecture Hall, Room B 0.32
  • Host: MPQ, Theory Division
In two dimensions, Projected Entangled-Pair States (PEPS) are elegant many-body wavefunctions which capture efficiently the quantum entanglement of ground states of local quantum spin Hamiltonians.

Combining the framework of PEPS with various symmetries, e.g. SU(2) spin
rotation symmetry, translation symmetry, and point group symmetry, which
are present in typical Heisenberg antiferromagnets, a comprehensive
classification of PEPS tensors on the square lattice has been achieved.
Using tensors belonging to some specific classes as a variational
manifold allows us to study frustrated magnets in a controlled way. To
illustrate the complexity of these manifolds, I will first present the
phase diagram of a one-parameter family of long-range resonating valence
bond (RVB) state, where we found a topological Z_2 RVB phase, sandwiched
by two critical phases. Then I will move on to using these manifolds to
study frustrated spin-1 antiferromagnets, where a nematic spin liquid
phase and a non-abelian chiral spin liquid phase have been identified.
Some perspectives will be discussed at the end.

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