Resumen: In this work we study the two and three-dimensional antiferromagnetic Ising model with an imaginary magnetic field iTheta at Theta=Pi. In order to perform numerical simulations of the system we introduce a new geometric algorithm not affected by the sign problem. Our results for the 2D model are in agreement with the analytical solution. We also present new results for the 3D model which are qualitatively in agreement with mean-field predictions. Idioma: Inglés DOI: 10.1016/j.nuclphysb.2014.04.004 Año: 2014 Publicado en: NUCLEAR PHYSICS B 883, 1 (2014), 656-684 ISSN: 0550-3213 Factor impacto JCR: 3.929 (2014) Categ. JCR: PHYSICS, PARTICLES & FIELDS rank: 7 / 27 = 0.259 (2014) - Q2 - T1 Financiación: info:eu-repo/grantAgreement/ES/DGA/E24-2 Financiación: info:eu-repo/grantAgreement/ES/MICINN/FPA2009-09638 Tipo y forma: Artículo (Versión definitiva) Área (Departamento): Física Teórica (Departamento de Física Teórica)