"Detecting Multipartite Entanglement Through Spectroscopy"
In this talk, I discuss the connection between detecting multipartite entanglement in a quantum system and the dynamical response functions with which one can probe a quantum system. This connection is afforded through the Quantum Fisher Information, a notion from quantum metrology parameterizing how accurately a parameter can be measured. The QFI however is also an entanglement witness that can be determined from spectroscopic measurements. While the QFI has been used to detect entanglement through inelastic neutron scattering measurements, it has yet to be extended to other spectroscopies. We show how this may be done for both single particle spectroscopies (i.e., scanning tunneling microscopy and angle resolved photo emission) as well as resonant inelastic x-ray scattering (RIXS). In the case of single particle spectroscopies, we show that it is possible to obtain more fine grained information on multipartite entanglement than is typical. In the case of RIXS, we show how multipartite entanglement can be extended to spectroscopies involving quantum operators that are not Hermitian.