Quantum criticality of a ${\mathbb{Z}}_3$ symmetric spin chain with long-range interactions

Based on large-scale density matrix renormalization group techniques, we investigate the critical behaviors of quantum three-state Potts chains with long-range interactions. Using fidelity susceptibility as an indicator, we obtain a complete phase diagram of the system. The results show that as the long-range interaction power $\alpha$ increases, the critical points $f_c^{\ast }$ shift towards lower values. In addition, the critical threshold ${\alpha }_c(\approx 1.43$) of the long-range interaction power is obtained for the first time by a non-perturbative numerical method. This indicates that the critical behavior of the system can be naturally divided into two distinct universality classes, namely the long-range ($\alpha \text{textless}{\alpha }_c$) and short-range ($\alpha \text{textgreater}{\alpha }_c$) universality classes, qualitatively consistent with the classical ${\phi }^3$ effective field theory. This work provides a useful reference for further research on phase transitions in quantum spin chains with long-range interaction.