Advancing Quantum Measurement for Gravitational Physics

Optical interferometer observatories such as LIGO have begun a new era of astrophysics by measuring the length of their vast arms to such precision that gravitational waves from distant collisions of black holes and neutron stars are now regularly observed. This past run, the global gravitational wave network itself entered a new era, whereby every detector has enhanced sensitivity using quantum squeezed states of light, limited by measurement back-action and optical loss. In its latest observing run, LIGO is now operating with its advanced, "Frequency-dependent squeezing" upgrade to now surpass two limitations to its quantum-limited sensitivity. Given the proven and maturing effectiveness of squeezing, we should now explore what are future avenues to utilize quantum mechanics to improve Gravitational-Wave observatories, interferometers, and physics experiments in general. This talk will outline the basis of squeezing's effectiveness, it's fundamental limitations, and our current understanding of how to bypass them for future observatories such as Cosmic Explorer, as well as for specific scientific objectives such as inferences on populations.