Probing intermediate-mass black hole binaries

Through probing gravitational waves (GWs) in the universe, scientists have identified stellar mass black holes and supermassive black holes. This leads to the question of whether intermediate-mass black holes (IMBHs) exist. Although they have not yet been observed, theoretical evidence points to IMBHs being the missing step in supermassive black hole formation.

Author Alejandro Torres-Orjuela studied the possibility of using atom interferometers (AIs) to detect GW sources containing IMBHs. The detection of IMBH binaries has always sparked controversy, but AIs can observe the intermediate band of GWs, which existing and expected missions cannot do. By assessing the simulated accuracy of AI identification of a merging IMBH binary, the author discovered an effective IMBH detection scheme.

“AIs have two operation modes—a broadband mode covering a big range of frequencies, and a resonant mode that only covers a narrow band but with better accuracy,” said author Alejandro Torres-Orjuela. “By using the broadband mode to detect the early inspiral signal, and the resonant mode for the later merger signal, one can obtain accurate results for detecting IMBHs.”

The author also studied both short (30s) and long (600s) detection gaps when switching from broadband to resonant mode. Detection accuracy increased for most parameters compared to performing full signal detection in broadband.

In the future, the author plans to explore using similar detection schemes to test general relativity.

“Detecting the quasi-normal modes of merging black holes is one of the big goals in gravitational wave astronomy,” said Torres-Orjuela. “Using a scheme similar to the one I presented, we should be able to achieve high detection accuracy.”

Source: “Detecting intermediate-mass black hole binaries with atom interferometer observatories: Using the resonant mode for the merger phase,” by Alejandro Torres-Orjuela, AVS Quantum Science (2023). The article can be accessed at https://doi.org/10.1116/5.0162505 .

This paper is part of the Large Scale Quantum Detectors Collection, learn more here .