DR. ROBERT WARD

Modern laser interferometric gravitational wave detectors are giant, broadband opto-mechanical sensors that explore the audio spectrum from 1 Hz to 10 kHz. This entire frequency band is expected to contain signals from dynamical astrophysical processes of great interest, such as the inspiral and merger of compact objects, stellar core-collapse supernovae, spinning neutron stars and various astrophysical backgrounds. Even more tantalising are the unpredicted sources. Fully exploiting the potential of ground based gravitational wave detectors requires reaching the so-called 'fundamental' sensitivity limits imposed by seismic, thermal, and quantum noises. In reality, detectors are limited at low audio frequencies (below about 30 Hz) by technical noises, mostly self-induced from the control systems. The large number of coupled degrees-of-freedom, combined with physical processes at differing time scales, makes the controls problem especially challenging. Future gravitational wave detectors, such as the proposed Einstein Telescope and the concept for LIGO Cosmic Explorer, have even more ambitious goals for low frequency sensitivity. In this talk the speaker will discuss the research program at the Australian National University, which targets both the ‘fundamental’ and ‘technical’ noises that limit our sensitivity.