Novel quantum phase transition from bounded to extensive entanglement
Significance One of the main quests of many-body physics and quantum information is to understand various quantum phases and in particular the entanglement present in them. In this work we have uncovered a unique, physically transparent quantum phase transition in a spin chain where entanglement entropy itself jumps from low scaling, most typical for gapped models and short-range correlations, to a critical phase where the scaling exhibits an extraordinary amount of entanglement. This discovery pushes the boundaries of a possible range of nonlocal quantum correlations displayed by local Hamiltonians and opens a door to fundamental and practical questions about the interplay of entanglement and locality in many-body systems.