  This study rigorously investigates the phenomenon of a pseudo-transition in a
minimal spinpseudospin model, serving as a simplified model of one-dimensional
cuprate chains [CuO]n, by making use of the transfer-matrix method. The studied
spin-pseudospin model of one-dimensional cuprate chains [CuO]n reveals a
peculiar pseudo-transition between a charged-ordered phase and an
antiferromagnetic phase, which is accompanied with anomalous behavior of
magnetic and thermodynamic quantities. While the entropy and short-range
correlations undergo near the pseudo-transition steep continuous changes
reminiscent of a discontinuous phase transition, the specific heat displays a
sizable sharp peak akin to a continuous phase transition.
