Influence of Lorentz violation on Dirac quasinormal modes in the Schwarzschild black hole spacetime

Using the third-order WKB approximation and monodromy methods, we investigate the influence of the Lorentz violating coefficient b (associated with a special axial-vector b_μ field ) on Dirac quasinormal modes in the Schwarzschild black hole spacetime. At fundamental overtone, the real part decreases linearly as the parameter b increases. But the variation of the imaginary part with b becomes more complex. For the larger multiple moment k, the magnitude of the imaginary part increases with the increase of b, which means that the presence of Lorentz violation makes Dirac field damps more rapidly. At high overtones, it is found that the real part of highly-damped quasinormal frequency does not tend to zero, which is quite different from the asymptotic Dirac quasinormal modes without Lorentz violation.