[Seminar] Topological frustration in a quantum spin ladder

Speaker
Prof. Michael Lawler - The Cornell University / Binghamton University

Title
Topological frustration in a quantum spin ladder

Abstract
Topological frustration is the existence of zero modes that are robust to many but not all distortions of the Hamiltonian. It is particularly interesting when local distortions preserve the zero modes but exponentially smaller further neighbor distortions lift them--a kind of locality protected topological phase. In this case, it predicts the existence of unexpected low energy modes. Here we study the fate of topological frustration in magnets when the spin is reduced from infinite to a finite value. We do so in a geometrically frustrated spin ladder model similar to kagome and pyrochlore heisenberg models but with infinitely many conserved quantities that aid the solution. Our results show a form of topological frustration is preserved from infinite S to finite S through the existence of symmetry-protected topological eigenstates arising at small but finite energy. Our results also shed light on the role of tensor network methods in the solution of large spin frustrated magnets and suggests they might be useful for studying large finite-S kagome magnets.

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Meeting ID: 926 4852 6912

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