学术报告（张晓 2026.1.30）

摘要：In this talk, we show that massive Majorana spinors do not exist if they are t-dependent or $\phi$-dependent in Kerr, or Kerr-(A)dS spacetimes. For massless Majorana spinors in the non-extreme Kerr spacetime, the Dirac equation can be separated into radial and angular equations, parameterized by two complex constants $\varpsilon_1, \varpsilon_2$. If at least one of them is zero, massless Majorana spinors can be solved explicitly. If they are both nonzero, we prove the nonexistence of massless time-periodic Majorana spinors in the non-extreme Kerr spacetime which are $L^p$ outside the event horizon for $0<p\leq 6/(l\varpsilon_1l+|\varpsilon_2l+2)$. We then provide the Hamiltonian formulation for massless Majorana spinors and prove that the self-adjointness of the Hamiltonian leads to the angular momentum $a = 0$ and spacetime reduces to the Schwarzschild spacetime, moreover, the massless Majorana spinor must be $\phi$-independent. Finally, we show that, in the Schwarzschild spacetime, for initial data with L^2 decay at infinity, the probability of the massless Majorana spinors to be in any compact region of space tends to zero as time tends to infinity. This talk is based on the joint work with Tianyuan Cai.