Analytic Expressions for Quasinormal Modes in Einstein–Aether Theory

Quasinormal frequencies in the Einstein–Aether theory have been extensively investigated with the help of numerical methods. Here we derive analytic expressions for quasinormal modes of test scalar, electromagnetic and Dirac fields, using the higher-order WKB method and expansion in terms of $$1/\ell$$ , where $$\ell$$ is the multipole number. The obtained analytic formulas are surprisingly precise and in agreement with previously published numerical data. In addition, we check the validity of the correspondence between null geodesics and eikonal quasinormal modes.