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On $c=1$ critical phases in anisotropic spin-1 chains

C. Degli Esposti Boschi·E. Ercolessi·F. Ortolani·M. Roncaglia
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Abstract

Quantum spin-1 chains may develop massless phases in presence of Ising-like and single-ion anisotropies. We have studied c=1 critical phases by means of both analytical techniques, including a mapping of the lattice Hamiltonian onto an O(2) nonlinear sigma model, and a multi-target DMRG algorithm which allows for accurate calculation of excited states. We find excellent quantitative agreement with the theoretical predictions and conclude that a pure Gaussian model, without any orbifold construction, describes correctly the low-energy physics of these critical phases. This combined analysis indicates that the multicritical point at large single-ion anisotropy does not belong to the same universality class as the Takhtajan-Babujian Hamiltonian as claimed in the past. A link between string-order correlation functions and twisting vertex operators, along the c=1 line that ends at this point, is also suggested.

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C. Degli Esposti Boschi, E. Ercolessi, F. Ortolani, M. Roncaglia. 2003-07-16. On $c=1$ critical phases in anisotropic spin-1 chains. https://doi.org/10.1140/epjb%2Fe2003-00299-7

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