Скачать или смотреть Quantum Mechanics - Time-Dependent Perturbation Theory : Transition Probability

Time-Dependent Perturbation Theory deals with to find the transition probability of a system when it undergoes from one unperturbed eigen state to another due to interaction with a time-dependent perturbation V(t). If the system is initially in an unperturbed eigen state of unperturbed Hamiltonian Ho,time-dependent perturbation theory aims to find the probability that the system will be found at a later time in another unperturbed state. This theory is most useful for studying processes of absorption and emission of radiation by atoms or,more generally,for treating the transitions of quantum systems from one energy level to another. Basically we solve the Schrodinger’s time-dependent equation using interaction picture. The Dyson series is obtained which allows for the calculation of the state vector up to the desired order in the perturbation. However,terms higher than first order become rapidly intractable. For most problems of atomic and nuclear physics, the first order is usually sufficient,therefore, the transition probability of first order has been obtained.