Discovering the QCD Axion with Black Holes and Gravitational Waves

By A. Arvanitaki, M. Baryakhtar, Xinlu Huang. 2014

417 citations recorded by the source corpus.

Advanced LIGO may be the first experiment to detect gravitational waves. Through superradiance of stellar black holes, it may also be the first experiment to discover the QCD axion with decay constant above the grand unification scale. When an axion’s Compton wavelength is comparable to the size of a black hole, the axion binds to the black hole, forming a “gravitational atom.” Through the superradiance process, the number of axions occupying the bound levels grows exponentially, extracting energy and angular momentum from the black hole. Axions transitioning between levels of the gravitational atom and axions annihilating to gravitons can produce observable gravitational wave signals. The signals are long lasting, monochromatic, and can be distinguished from ordinary astrophysical sources. We estimate up to O(1) transition events at aLIGO for an axion between 10-11 and 10-10  eV and up to 104 annihilation events for an axion between 10-13 and 10-11  eV. In the event of a null search, aLIGO can constrain the axion mass for a range of rapidly spinning black hole formation rates. Axion annihilations are also promising for much lighter masses at future lower-frequency gravitational wave observatories; the rates have large uncertainties, dominated by supermassive black hole spin distributions. Our projections for aLIGO are robust against perturbations from the black hole environment and account for our updated exclusion on the QCD axion of 6×10-13  eV

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/4af75b325ff3a5a4f219cec3741976a604de11df

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

1. Paolo Pani
2. R. Brito
3. V. Cardoso
4. F. Quevedo
5. Marco Peloso
6. Pablo Soler
7. Daniel G. Figueroa
8. A. Hebecker

In Nuclear and High Energy Physics

1. Paolo Pani
2. R. Brito
3. V. Cardoso
4. A. Hook
5. Eran Palti
6. F. Quevedo
7. A. Hebecker
8. Kiwoon Choi

Citations in the corpus

• Superradiance (2015, methodology): “[103].”
• TASI Lectures on the Strong CP Problem and Axions (2018, background): “7 Black hole superradiance Black hole superradiance utilizes the interesting physics that happens around a spinning black hole [81, 149, 150], which has a region of space near to the horizon called the ergosphere where”
• Detecting high-frequency gravitational waves with microwave cavities (2021, background): “[102] Asimina Arvanitaki, Masha Baryakhtar, and Xinlu Huang, “Discovering the QCD Axion with Black Holes and Gravitational Waves,” Phys.”
• Recent Progress in the Physics of Axions and Axion-Like Particles (2020, background): “5×109M provide the strong constraints on the existence of axions in the mass ranges of 10−13−10−11 eV, 10−19−10−16 eV, and 10−21−10−20 eV, respectively [80–84].”
• Factoring the strong CP problem (2017, background): “Black hole superradiance [66] puts constraints on very light axions.”
• Black hole formation from axion stars (2016, background): “We note that observations of spinning solar mass BHs exclude 3× 1017 GeV < fa < 1× 1019 GeV QCD axions [76], which excludes fa ∼ fTP, though superPlanckian QCD axions are allowed.”
• Superradiance: Energy Extraction, Black-Hole Bombs and Implications for Astrophysics and Particle Physics (2015, methodology): “[9, 483, 484], a bosonic condensate around a spinning BH as the one depicted in Fig.”