Here, the book gets difficult. Loudon dives into the interaction Hamiltonian, the rotating wave approximation, and the Wigner-Weisskopf theory of spontaneous emission. If you are a student of atomic physics, these chapters are essential for understanding how excited atoms actually decay.
: Including two-photon interference and beamsplitter theory. Quantum Jumps loudon quantum theory of light pdf
Most academic institutions provide free access to the ebook via platforms like Oxford Scholarship Online. Here, the book gets difficult
: The foundation of quantum mechanics, describing how energy is distributed in blackbody radiation. the rotating wave approximation