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Spin-1 chain with spin-1/2 excitations in the bulk

Diptiman Sen·Naveen Surendran
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Abstract

We present a spin-1 chain with a Hamiltonian which has three exactly solvable ground states. Two of these are fully dimerized, analogous to the Majumdar-Ghosh (MG) states of a spin-1/2 chain, while the third is of the Affleck-Kennedy-Lieb-Tasaki (AKLT) type. We use variational and numerical methods to study the low-energy excitations which interpolate between these ground states in different ways. In particular, there is a spin-1/2 excitation which interpolates between the MG and AKLT ground states; this is the lowest excitation of the system and it has a surprisingly small gap. We discuss generalizations of our model of spin fractionalization to higher spin chains and higher dimensions.

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Diptiman Sen, Naveen Surendran. 2007-03-17. Spin-1 chain with spin-1/2 excitations in the bulk. https://doi.org/10.1103/physrevb.75.104411

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