@article {655, title = {Critical points of coupled vector-Ising systems. Exact results}, journal = {J. Phys. A. Math. Theor.}, volume = {52}, year = {2019}, pages = {35LT02}, abstract = {We show that scale-invariant scattering theory allows to exactly determine the critical points of two-dimensional systems with coupled O(N) and Ising order parameters. The results are obtained for N continuous and include criticality of the loop gas type. In particular, for N = 1 we exhibit three critical lines intersecting at the Berezinskii-Kosterlitz-Thouless transition point of the Gaussian model and related to the Z$_{4}$ symmetry of the isotropic Ashkin-Teller model. For N = 2 we classify the critical points that can arise in the XY-Ising model and provide exact answers about the critical exponents of the fully frustrated XY model.}, doi = {10.1088/1751-8121/ab3055}, url = {https://iopscience.iop.org/article/10.1088/1751-8121/ab3055}, author = {Gesualdo Delfino and Noel Lamsen} }