Multipartite Entanglement Spectroscopy in a Quasi-one-dimensional Hubbard Model: A Single Particle Green’s Function Approach

We evaluate the multipartite entanglement in a quasi-one-dimensional Hubbard model by computing the quantum Fisher information (QFI) of a witness operator associated with the single-particle Green’s function. This method includes building two copies of the quasi-one-dimensional Hubbard model and a witness operator that hops between the two copies. Next, we numerically compute the QFI for a large system using the density matrix renormalization group (DMRG) technique and find that the amount of entanglement detected is sensitive to the wavevector of the hopping in the witness operator. This approach allows for experimentally detecting entanglement in many-body systems via scanning tunneling microscopy and angle-resolved photoemission probes.