Tree expansion in time-dependent perturbation theory

Time-Dependent Perturbation Theory

Our starting point is the set of eigenstates n of the unperturbed Hamiltonian 0 n H n E n = , notice we are not labeling with a zero, no 0 n E , because with a time-dependent Hamiltonian, energy will not be conserved, so it is pointless to look for energy corrections. What happens instead, provided the perturbation is not too large, is that the system makes transitions between the eigenstates n...

Time dependent perturbation theory in Quantum Cosmology

We describe radiative processes in Quantum Cosmology, from the solutions of the Wheeler De Witt equation. By virtue of this constraint equation, the quantum propagation of gravity is modified by the matter interaction hamiltonian at the level of amplitudes. In this we generalize previous works where gravity was coupled only to expectation values of matter operators. By a “reduction formula” we ...

Time-dependent Perturbation Theory in Quantum Mechanics

After revealing difficulties of the standard time-dependent perturbation theory in quantum mechanics mainly from the viewpoint of practical calculation, we propose a new quasi-canonical perturbation theory. In the new theory, the dynamics of physical observables, instead of that of coefficients of wave-function expansion, is formulated so that the gauge-invariance and correspondence principles ...

Notes 32 : Time - Dependent Perturbation Theory

Time-Dependent Perturbation Theory and Molecular Spectroscopy

II. Interaction of light with matter 7 A. Absorption of radiation by matter 10 B. Spontaneous emission 13 C. Selection Rules: Transitions within the same electronic state 15 1. Rotational Selection Rules 16 2. Vibrational Selection Rules 17 D. Pure Rotation Transitions 18 E. Vibration-Rotation Transitions 22 1. Q branches 24 F. Electronic-Rotational-Vibrational Transitions 25 G. Selection Rules...