From entanglement certification with quench dynamics to multipartite entanglement of interacting fermions

Multipartite entanglement, such as witnessed through the quantum Fisher information (QFI), is a crucial resource for quantum technologies, but its experimental certification is highly challenging. Here, we propose an experimentally friendly protocol to measure the QFI. It relies on recording the short-time dynamics of simple observables after a quench from a thermal state, works for spins, bosons, and fermions, and can be implemented in standard cold-atom experiments and other platforms with temporal control over the system Hamiltonian. To showcase the protocol, we simulate it for the one-dimensional Fermi-Hubbard model. Further, we establish a family of bounds connecting the QFI to multipartite mode entanglement for fermionic systems, which enable the detection of multipartite entanglement at sizable temperatures. Our work paves a way to experimentally accessing entanglement for quantum enhanced metrology.

Automated summary

The study introduces an experimentally friendly protocol for measuring the quantum Fisher information, applicable to various types of particles. Through simulating fermionic systems, a set of bounds connecting QFI with multipartite mode entanglement is established, enabling the detection of multipartite entanglement at higher temperatures. This work lays the foundation for experimentally accessing entanglement in quantum enhanced metrology.