Chapter XV. Coherent State Representations

Fenglei Gu

Group-IV vacancy (G4V, or XV, where X = Si, Ge, Sn, Pb) color centers constitute a novel and promising class of defects in diamonds. This chapter reviews and refines the theoretical models for the XV systems, encompassing the intrinsic interactions, including spin-orbit coupling and electron-phonon interactions, and the external interactions involving strain, electric, light, and magnetic fields. Based on the refined model, we predict their properties, explain the experimental data, and suggest follow-up experiments. This article established a solid foundation for controlling the XV system, thus paving the way for quantum information processing.

Monique Combescure, Didier Robert

G. Reents, Stephen J. Summers

Lukong Cornelius Fai

This chapter shows how to construct path integral representation using a closure relation based on the eigenstates of the creation or the annihilation operators. It examines how coherent states are used to obtain a path integral representation of the partition function as well as calculating directly the trace defining the partition function. The chapter explores quantum field theory using the Feynman functional and diagrammatic techniques as foundations to apply Quantum Field Theory to a broad range of topics in physics. The minimum uncertainty wave packets for the harmonic oscillator were published as coherent states by Schrodinger. Coherent states have played an important role in many branches of physics and, in particular, quantum field theory and quantum optics. The most important property of coherent states is their overcompleteness in the Fock space, which implies that any vector of the Fock space can be expanded in terms of coherent states.