Tuning Advanced LIGO to kilohertz signals from neutron-star collisions
Gravitational waves produced at kilohertz frequencies in the aftermath of a neutron star collision can shed light on the behavior of matter at extreme temperatures and densities that are inaccessible to laboratory experiments. Gravitational-wave interferometers are limited by quantum noise at these frequencies but can be tuned via their optical configuration to maximize the probability of postmerger signal detection. We compare two such tuning strategies to turn Advanced LIGO into a postmerger-focused instrument: first, a wideband tuning that enhances the instrument's signal-to-noise ratio 40–80% broadly above 1 kHz relative to the baseline, with a modest sensitivity penalty at lower frequencies; second, a "detuned" configuration that provides even more enhancement than the wideband tuning, but over only a narrow frequency band and at the expense of substantially worse quantum noise performance elsewhere. With an optimistic accounting for instrument loss and uncertainty in postmerger parameters, the detuned instrument has a ≲ 40% sensitivity improvement compared to the wideband instrument.
© 2021 American Physical Society. (Received 29 October 2020; accepted 17 December 2020; published 11 January 2021) The authors thank the National Science Foundation for support under Grant No. PHY–0555406. E. D. H. is supported by the MathWorks, Inc. The authors acknowledge fruitful discussions with Haixing Miao and Hartmut Grote in the early stages of this work, as well as valuable inputs from Stefan Ballmer, Teng Zhang and Peter Fritschel. Upper bounds on the SRC loss were based on data from Valera Frolov.
Submitted - 2010.15735.pdf
Published - PhysRevD.103.022002.pdf