Gaussian-type light bullets in power-law nonlinear media with PT-symmetricPT-symmetric potentials

The (3+1)-dimensional nonlinear Schrödinger equation with power-law nonlinearities in two kinds of PT-symmetricPT-symmetric potentials is investigated, and two kinds of Gaussian-type light bullet (LB) solutions are analytically derived. Based on these analytical solutions, the powers, power-flow densities and the phase switches are discussed. The linear stability analysis and the direct numerical simulation show that LB solutions are stable only when the imaginary parts of PT-symmetricPT-symmetric potentials are below some thresholds in the focusing power-law nonlinear media, while they are always unstable in the defocusing power-law nonlinear media.