Entanglement entropy and the Berezinskii–Kosterlitz–Thouless phase transition in the J1–J2 Heisenberg chain

• The BKT-type transition in the J1J1–J2J2 model is clearly indicated by the two-site and block entanglement entropies.
• The corresponding size dependent scaling behaviors are given, respectively.
• Another indicator with different scaling behavior is found in the block entanglement entropy.

Using the density matrix renormalization group (DMRG) technique, we study the Berezinskii–Kosterlitz–Thouless (BKT) quantum phase transition (QPT) in the J1J1–J2J2 Heisenberg chain model from the quantum entanglement point of view. It is found that the gap behavior between two neighboring two-site entanglement entropies as well as the first derivative of both the two-site entropy and the block entropy can be used as indicators for the BKT phase transition in this model. The corresponding size dependent scaling behaviors are analyzed, respectively. Our numerical results give direct evidence for the effectiveness of the entanglement in the BKT-type QPT indicating from different aspects.