Anomalous tricritical behaviour in the coil-globule transition of a single polymer chain

We investigate a model of self-avoiding walk exhibiting a first-order coil-globule transition. This first-order nature, unravelled through the coexistence of distinct coil and globule populations, has observable consequences on the scaling properties. A thorough analysis of the size dependence of the mean radius of gyration evidences a breakdown of the plain tricritical scaling behaviour. In some regimes, anomalous exponents are observed in the transition region and logarithmic corrections arise along the coexistence curve.