Quantum Optics Seminar by Farid Khalili

Spin system with a negative effective mass for future Gravitational Wave Detectors.

Using the additional spin systems with negative effective mass, it is possible  to suppress the quantum noise in GW detectors across the almost entire frequency  bandwidth relevant for gravitational wave observation [1].  However, this scheme requires that the effective eigen frequency of the spin  system should be close to the one of the pendulum modes of the GW detectors' mirrors, which could be problematic due to the technological constraints. Here we  propose the alternative approach of matching the effective, instead of the physical, response functions of the spin system and the probe mirrors by using a two-channel homodyne measurement with optimally tuned homodyne angles.

 

  1. Overcoming the Standard Quantum Limit in Gravitational Wave Detectors Using Spin Systems with a Negative Effective Mass. F. Khalili and E. S. Polzik, PRL 121, 031101 (2018).