Exact wave-function dualities of quantum spin liquids

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Classical vertex model dualities in a family of 2D frustrated quantum antiferromagnets

Authors

Shankar Balasubramanian, Victor Galitski, Ashvin Vishwanath

Abstract

We study a general class of easy-axis spin models on a lattice of corner sharing even-sided polygons with all-to-all interactions within a plaquette. The low energy description corresponds to a quantum dimer model on a dual lattice of even coordination number with a multi dimer constraint. At an appropriately constructed frustration-free Rokhsar-Kivelson (RK) point, the ground state wavefunction can be exactly mapped onto a classical vertex model on the dual lattice. When the dual lattice is bipartite, the vertex models are bonded and are self dual under Wegner's duality, with the self dual point corresponding to the RK point of the original multi-dimer model. We argue that the self dual point is a critical point based on known exact solutions to some of the vertex models. When the dual lattice is non-bipartite, the vertex model is arrowed, and we use numerical methods to argue that there is no phase transition as a function of the vertex weights. Motivated by these wavefunction dualities, we construct two other distinct families of frustration-free Hamiltonians whose ground states can be mapped onto these vertex models. Many of these RK Hamiltonians provably host $\mathbb{Z}_2$ topologically ordered phases.

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4 comments

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toivar

This is a very exciting result. Can this duality be used in the quantum circuits?

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scicastboard

That's a great question. We jut posted a paper on chaotic quantum circuits, such as in the picture below (2D & 3D). Most circuits are chaotic, but there is a special class of integrable circuits: if the gates satisfy a certain set of (Young-Baxter) relations. Then, there may be pairs of dual circuits, but what topological order means for circuits is unclear.


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scicastboard

Equation (1) of the paper is generalizable to quantum computing architectures. 

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scicastboard

Actually, most equations in Sec. 1 are generalizable. In particular, one can use this theory to caclulate $K(t)= \langle |\exp{i\hat{H}t|^2\rangle$

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