Detecting topological phase transitions in long range interacting Kitaev chain through the entanglement between disconnected partitions
Saikat Mondal, Souvik Kumar Bandyopadhyay, Sourav Bhattacharjee, Amit Dutta
Abstract
We explore the behavior of the disconnected entanglement entropy (DEE) across the topological phases of a long range interacting Kitaev chain where the long range interactions decay as a power law with an exponent $\alpha$. We show that while the DEE may not remain invariant deep within the topologically non-trivial phase when $\alpha<1$, it still shows a quantized discontinuous jump at the quantum critical point and can act as a strong marker for the detection of topological phase transition for the long range interacting systems. We also study the time evolution of the disconnected entanglement entropy after a sudden quench of chemical potential within same phase. In the short range limit of a finite chain, the DEE is expected to remain constant upto a critical time which diverges in the thermodynamic limit. However, we find that no such critical time exists in the presence of long range interactions ($\alpha<1$).