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arXiv · 2604.11606

The Widom line in the Ising model on a decorated bilayer lattice

Joseph Chapman·Justas Gidziunas·Bruno Tomasello·Sam Carr
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Abstract

There has been much recent interest devoted to a class of frustrated one-dimensional statistical mechanics lattice models which exhibit sharp thermodynamics. In this work, we study an extension of one of these models to two dimensions; the Ising model on a decorated bilayer lattice. We show that the pseudo-transitions of the one-dimensional models become a real first order phase transition in this two-dimensional analogue. Moreover, the pseudo-transition is found to still exist above a bi-critical point. This can be characterised as a Widom line, which allows a re-interpretation of the physics in the previously studied one-dimensional models.

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Joseph Chapman, Justas Gidziunas, Bruno Tomasello, Sam Carr. 2026-04-13. The Widom line in the Ising model on a decorated bilayer lattice. https://doi.org/10.1088/1742-5468%2Fae8438

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