| dc.description.abstract | The non-trivial vacuum structure in QCD leads to addition of an extra term to its Lagrangian. This term serves as the source of CP violation in QCD. Introducing a new pseudoscalar particle called axion can retain the CP invariance. This new particle also decays into two photons naturally which could provide a way of detection. We review the origin of the axion and the previous lasing model in chapter I. The previous lasing model assumes spherical symmetry in both momentum and coordinate space. We build extensions to the previous lasing model when the distribution in momentum and coordinate space are not spherically symmetric, in chapter II and chapter III respectively. We find that the photon number density components in both spaces are determined by these of axion. The background spacetime of the previous lasing model is set in Minkowskian. We generalize the previous lasing model when the underlying spacetime is not Minkowskian but static in chapter IV. As an example, besides small distortion from gravity, we show that lasing occurs from hadronic axion cluster far way from a black hole of a solar mass. In chapter V, we propose a classical potential that roughly describes the self interaction between axions. Using this potential, we find there are different relativistic regions in an axiton. At the surface of an axiton, the axions could be nonrelativistic which could result in lasing. We apply the previous lasing model specifically to axitons discussed in the recent literature and find that stable relativistic axiton may become unstable through cascade of surface lasing. | |
