The counter-intuitive aspects of quantum physics have been long illustrated by thought experiments, from Einstein's photon box to Schrödinger's cat. These experiments have now become real, with single particles - electrons, atoms, or photons - directly unveiling the strange features of the quantum. State superpositions, entanglement and complementarity define a novel quantum logic which can be harnessed for information processing, raising great hopes for applications. This book describes a class of such thought experiments made real. Juggling with atoms and photons confined in cavities, ions or cold atoms in traps, is here an incentive to shed a new light on the basic concepts of quantum physics. Measurement processes and decoherence at the quantum-classical boundary are highlighted. This volume, which combines theory and experiments, will be of interest to students in quantum physics, teachers seeking illustrations for their lectures and new problem sets, researchers in quantum optics and quantum information.

This important proceedings volume highlights the major scientific achievement of the last decade in atomic physics, namely the creation of the gaseous Bose-Einstein condensate, which was featured prominently at the XVIII International Conference on Atomic Physics (ICAP2002). Two recipients of the 2001 Nobel Prize delivered lectures at the meeting. Among the topics discussed were novel processes leading to degenerate Fermi gases in atom traps, creation of cold molecules, condensates in optical lattices, atoms in intense fields, tests of fundamental symmetries, quantum control and information, time and frequency standards.

The physics of strong light-matter coupling has been addressed in different scientific communities over the last three decades. Since the early eighties, atoms coupled to optical and microwave cavities have led to pioneering demonstrations of cavity quantum electrodynamics, Gedanken experiments, and building blocks for quantum information processing, for which the Nobel Prize in Physics was awarded in 2012. In the framework of semiconducting devices, strong coupling has allowed investigations into the physics of Bose gases in solid-state environments, and the latter holds promise for exploiting light-matter interaction at the single-photon level in scalable architectures. More recently, impressive developments in the so-called superconducting circuit QED have opened another fundamental playground to revisit cavity quantum electrodynamics for practical and fundamental purposes. This book aims at developing the necessary interface between these communities, by providing future researchers with a robust conceptual, theoretical and experimental basis on strong light-matter coupling, both in the classical and in the quantum regimes. In addition, the emphasis is on new forefront research topics currently developed around the physics of strong light-matter interaction in the atomic and solid-state scenarios.

Prototypical quantum optics models, such as the Jaynes–Cummings, Rabi, Tavis–Cummings, and Dicke models, are commonly analyzed with diverse techniques, including analytical exact solutions, mean-field theory, exact diagonalization, and so on. Analysis of these systems strongly depends on their symmetries, ranging, e.g., from a U(1) group in the Jaynes–Cummings model to a Z2 symmetry in the full-fledged quantum Rabi model. In recent years, novel regimes of light–matter interactions, namely, the ultrastrong and deep-strong coupling regimes, have been attracting an increasing amount of interest. The quantum Rabi and Dicke models in these exotic regimes present new features, such as collapses and revivals of the population, bounces of photon-number wave packets, as well as the breakdown of the rotating-wave approximation. Symmetries also play an important role in these regimes and will additionally change depending on whether the few- or many-qubit systems considered have associated inhomogeneous or equal couplings to the bosonic mode. Moreover, there is a growing interest in proposing and carrying out quantum simulations of these models in quantum platforms such as trapped ions, superconducting circuits, and quantum photonics. In this Special Issue Reprint, we have gathered a series of articles related to symmetry in quantum optics models, including the quantum Rabi model and its symmetries, Floquet topological quantum states in optically driven semiconductors, the spin–boson model as a simulator of non-Markovian multiphoton Jaynes–Cummings models, parity-assisted generation of nonclassical states of light in circuit quantum electrodynamics, and quasiprobability distribution functions from fractional Fourier transforms.

Presents the lecture notes of the Les Houches Summer School on Quantum entanglement and information processing. This book aims to establish connections between the communities of quantum optics and of quantum electronic devices working in the area of quantum computing. It is useful for graduate students with a basic knowledge of quantum mechanics.

With the launch of the Quantum Technology Flagship Programme by the European Commission, developments in the realization of new technologies based on quantum physics have been recognized as a priority. These are important for cryptographic techniques for telecommunications security, new computing hardware that can solve problems so far inaccessible even to the latest generation of supercomputers, and precision standards and sensors with important applications ranging from materials science to medical diagnostics. This book presents a collection of lectures from the International School of Physics Enrico Fermi on Nanoscale Quantum Optics, held in Varenna, Italy, from 23 – 28 July 2018. The course was attended by 60 students, researchers and lecturers, and provided an opportunity to train a new generation of scientists on topics that promise great innovations in science and technology. Included here are 9 lectures and seminars and 3 poster contributions from the school. Subjects covered include: basic concepts for quantum optics and quantum technologies; materials for quantum nanophotonics; quantum optics and non-classical light generation; creating quantum correlations between quantum-dot spins; platforms for telecom-entangled photon sources; nanoscale sensing and quantum coherence; and nano-optomechanics, among others. The book offers a valuable overview of the state-of-the-art and current trends in nanoscale quantum optics. It will be invaluable for all those with an interest in this subject.