Coexistence of excited states in confined ising systems
Using the density-matrix renormalization-group method we study the two-dimensional Ising model in an infinite strip geometry with free-boundary conditions. The renormalization scheme enables us to consider systems of width up to 300 (lattice spacings) and study the influence of the bulk magnetic field on correlation function structure for all temperatures. From our numerical results we have determined the crossover line for the correlation length related to the coexistence of the excited states. A detailed scaling study of this line is performed. Our numerical results support and further specify previous conclusions reached by Abraham, Parry, and Upton based on the bubble model of correlations.
Drzewinski
A
Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 1410, 50-950 Wroclaw 2, Poland.