Low-temperature thermodynamics of the two-leg ladder Ising model with trimer rungs: A mystery explained

Abstract: Recently, a surprising low-temperature behavior has been revealed in a two-leg ladder Ising model with trimer rungs (Weiguo Yin, arXiv:2006.08921). Motivated by these findings, we study this model from another perspective and demonstrate that the reported observations are related to a critical phenomenon in the standard Ising chain. We also discuss a related curiosity, namely, the emergence of a power-law behavior characterized by quasicritical exponents.