Study On Novel Quantum-optical Effects Of An Atom Inside A Kerr Nonlinear Blackbody

Blackbody radiation, which is one of the origins of quantum theory, is always being one of the hot topics in physics.The Kerr nonlinear blackbody is a novel kind of blackbody which should be of great importance in theory and application. In this thesis, quantum-optical effects of an atom in a Kerr nonlinear blackbody are discussed. The content can be mainly divided into the following five parts:(1)One of the vacuum effect:the atomic spontaneous-emission effect is inves-tigated. A reservoir theory has been used to derive the master equation of a two-level atom in a Kerr-nonlinear blackbody. The atomic decay rate is obtained analytically. It is found that atom in an excited state decays exponentially. However, compared to that in normal free space, the decay rate in a Kerr nonlinear blackbody is modified by two factors:a linear-contribution factor and a nonlinear-contribution factor. The nonlinear-contribution factor is a function of Kerr-nonlinear coefficient and temper-ature. Below a transition temperature Tc, the value of nonlinear-contribution factor is always larger than unity. That is to say, the atomic spontaneous emission can be enhanced in a Kerr nonlinear blackbody.(2) Another vacuum effect:the Lamb shift of a Hydrogen atom in a Kerr nonlin-ear blackbody is investigated by using nonrelativistic quantum electrodynamic the-ory. The result shows that, compared to that in normal vacuum, the Lamb shift in a Kerr nonlinear blackbody is also modified by two factors mentioned above.At cer-tain conditions, the Lamb shift in a Kerr nonlinear blackbody can get much larger value than that in normal vacuum, which is term as giant Lamb shift. The physical origin and practical application of giant Lamb shift in a Kerr nonlinear blackbody are also discussed.(3) The Stark effect and depopulation rate effect that caused by atomic emission and reabsorption of real photons in a Kerr nonlinear blackbody are discussed. It is shown that below a transition temperature Tc, the two effects are equally modified. the values of the two effects in a Kerr nonlinear blackbody are correspondingly larger than those in a normal blackbody. At proper conditions, the value of the two effects for atomic ground state in a Kerr nonlinear blackbody can be larger than those for some Rydberg states in normal blackbody.(4) The atomic dipole squeezing effect are discussed. The condition of atomic dipole squeezing are formulated by using atomic master equation. It is found that the atomic dipole squeezing effect in a Kerr nonlinear blackbody depends on the Kerr nonlinear coefficient and temperature. Below a transition temperature Tc,the atomic dipole squeezing effect is attenuated much quicker with time than that in a normal blackbody.(5) The thermodynamic properties of an atom in a Kerr nonlinear blackbody are investigated. The Helmholtz free energy is obtained by using the thermodynamic perturbation theory. The result shows that the free energy depends on the Kerr nonlinear coefficient and temperature. Below a transition temperature Tc, the increment of free energy of an atom in a Kerr nonlinear blackbody can be larger than that in a normal blackbody.