Discuss the concept of entanglement spectrum and its significance in studying topological phases of matter.

The entanglement spectrum is the set of eigenvalues of the reduced density matrix obtained by partitioning a quantum system. It provides detailed information about the entanglement structure and is particularly significant in studying topological phases of matter. The low-lying part of the entanglement spectrum can reveal edge states and topological invariants, offering a powerful tool to characterize and distinguish between different topological phases without relying on local order parameters.