Abstract
The von Neumann entanglement entropy is used to estimate the critical point of the mixed ferro-antiferromagnetic three-state quantum Potts model , where and are standard three-state Potts spin operators and is the antiferromagnetic coupling parameter. This critical point value gives improved estimates for two Kosterlitz-Thouless transition points in the antiferromagnetic () region of the phase diagram of the three-state quantum chiral clock model, where and are, respectively, the chirality and coupling parameters in the clock model. These are the transition points at between incommensurate and commensurate phases and at between disordered and incommensurate phases. The von Neumann entropy is also used to calculate the central charge of the underlying conformal field theory in the massless phase . The estimate in this phase is consistent with the known exact value at the particular point corresponding to the purely antiferromagnetic three-state quantum Potts model. The algebraic decay of the Potts spin-spin correlation in the massless phase is used to estimate the continuously varying critical exponent .
1 More- Received 19 September 2016
- Revised 24 November 2016
DOI:https://doi.org/10.1103/PhysRevB.95.014419
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