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

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.

7 pages including 4 figures; this is the published version of the paper

References in corpus (3)

• Observation of extended scattering continua characteristic of spin fractionalization in the 2D frustrated quantum magnet Cs2CuCl4 by neutron scattering
• Resonating valence bond wave function for the two dimensional fractional spin liquid
• General topological features and instanton vacuum in quantum Hall and spin liquids

Cited by in corpus (5)

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• Matrix Product States: Symmetries and Two-Body Hamiltonians
• Spin 3/2 dimer model
• Two-dimensional spin-1 frustrated Heisenberg model with valence-bond ground states
• Exact Fractionalized Ground States in an Extended Spin-1 Kitaev Chain