Non-hermitian tricriticality in the Blume-Capel model with imaginary field

G. von Gehlen

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arXiv · hep-th/9402143

Non-hermitian tricriticality in the Blume-Capel model with imaginary field

G. von Gehlen

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Abstract

Using finite-size-scaling methods, we study the quantum chain version of the spin-$1$-Blume-Capel model coupled to an imaginary field. The aim is to realize higher order non-unitary conformal field theories in a simple Ising-type spin model. We find that the first ground-state level crossing in the high-temperature phase leads to a second-order phase transition of the Yang-Lee universality class (central charge $c=-22/5$). The Yang-Lee transition region ends at a line of a new type of tricriticality, where the {\em three} lowest energy levels become degenerate. The analysis of the spectrum at two points on this line gives good evidence that this line belongs to the universality class of the ${\cal M}_{2,7}$-conformal theory with $c=-68/7$.

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G. von Gehlen. 1994-02-25. Non-hermitian tricriticality in the Blume-Capel model with imaginary field. https://arxiv.org/abs/hep-th/9402143

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