A Quick Introduction to the strong coupling regime of Cavity Quantum Electrodynamics: applications and fundamental quantum theory

TL;DR

This paper introduces the strong coupling regime of Cavity Quantum Electrodynamics (QED), discussing its fundamental principles, key effects, applications in quantum measurement, and issues related to decoherence, aimed at making the topic accessible to physicists.

Contribution

It provides a concise overview of the strong coupling regime in cavity QED, highlighting its applications and fundamental questions about decoherence and measurement.

Findings

Review of the strong coupling regime fundamentals

Discussion of quantum gate protocols using cavity QED

Analysis of decoherence issues in quantum systems

Abstract

Since the photon box gedanken experiments of several of the founding fathers of modern physics, considerable progress has been made in differentiating the quantum and classical worlds. In this pursuit, the cavity as an open quantum system has been indispensable. From the quantization of the atom and field within a superconducting cavity, a unique realm of EPR type entanglement has emerged. In this way, dynamical evolution of the system in the strong coupling regime is intimately tied with the coupling of an atom with a single resonant or non-resonant mode within the cavity. More specifically, the cavity can be prepared so that the atom is detected in a desired state. Here, the essentials of the strong coupling regime of Cavity Quantum Electrodynamics (QED) are reviewed for cavities tuned with a single atomic transition. A brief introduction of the systems is followed by an approach of the more striking effects, leading towards Ramsey Interferometry and Quantum Non-Demolition measurements as means for quantum gate protocol. Because the integrity of the atom and photon states is important for the advancement of quantum computation, a brief discussion of the decoherence problems is also presented. This document is meant to introduce the topic in a way that makes it easily accessible to those working in closely related areas of physics, and to highlight key applications and some basic questions concerning decoherence and the measurement problem.