Sharp decay estimates for massless Dirac fields on a Schwarzschild background

Understand

We consider the explicit asymptotic profile of massless Dirac fields on a Schwarzschild background.

• First, we prove for the spin $s=\pm \frac{1}{2}$ components of the Dirac field a uniform bound of a positive definite energy and an integrated local energy decay estimate from a symmetric hyperbolic wave system.
• Based on these estimates, we further show that these components have globally pointwise decay $fv^{-3/2-s}\tau^{-5/2+s}$ as both an upper and a lower bound outside the black hole, with function $f$ finite and explicitly expressed in terms of the initial data and the coordinates.
• This establishes the validity of the conjectured Price's law for massless Dirac fields outside a Schwarzschild black hole.