PART I: INTRODUCTION AND BACKGROUND 1. Introduction 2. Classical optics 3. Quantum mechanics 4. Radiative transitions in atoms PART II: PHOTONS 5. Photon statistics 6. Photon antibunching 7. Coherent states and squeezed light 8. Photon number states PART III: ATOM-PHOTON INTERACTIONS 9. Resonant light-atom interactions 10. Atoms in cavities 11. Cold atoms PART IV: QUANTUM INFORMATION PROCESSING 12. Quantum cryptography 13. Quantum computing 14. Entangled states and quantum teleportation APPENDICES A. Poisson statistics B. Parametric amplification C. The density of states D. Low dimensional semiconductor structures E. Nuclear magnetic resonance F. Bose-Einstein condensation
Introduction.-A few new ideas and results in connection with the coherent interaction processes of X-rays in crystals are presented in this talk.This includes the discussion of interaction processes of X-rays and electrons associated with the interference in crystals.The interference is the simplest phenomenon which establishes a correlation between electrons or photons in crystals and thereby introduces coherence in the final output.In the case of X-rays and electrons the most fundamental interference phenomenon is the Bragg scattering in crystals.This is essentially the interaction of electromagnetic waves in case of X-rays and the de Broglie waves in the case of electrons which are to be scattered by the periodic lattice waves involved in the scattering process.In Ewald's [I] dynamical theory of X-ray interference the scattering elements of the crystal act as vibrating dipoles at the lattice sites and the problem is to find in the crystal a balanced or self-consistent state of electromagnetic field and the dipole waves.In Ewald's [I] dynamical theory explaining the Bragg scattering, the scattered waves have the same angular frequency coo of the incident wave.Slater [2] described the interaction between the inci-