The first quantum revolution started in the early 20th century and gave us new rules that govern physical reality. Accordingly, many devices that changed dramatically our lifestyle, such as transistors, medical scanners and lasers, appeared in the market. This was the origin of quantum technology, which allows us to organize and control the components of a complex system governed by the laws of quantum physics. This is in sharp contrast to conventional technology, which can only be understood within the framework of classical mechanics. We are now in the middle of a second quantum revolution. Although quantum mechanics is nowadays a mature discipline, quantum engineering as a technology is now emerging in its own right. We are about to manipulate and sense individual particles, measuring and exploiting their quantum properties. This is bringing major technical advances in many different areas, including computing, sensors, simulations, cryptography and telecommunications. The present collection of selected papers is a clear demonstration of the tremendous vitality of the field. The issue is composed of contributions from world leading researchers in quantum optics and quantum information, and presents viewpoints, both theoretical and experimental, on a variety of modern problems.

The term 'nonclassical states' refers to the quantum states that cannot be produced in the usual sources of light, such as lasers or lamps, rather than those requiring more sophisticated apparatus for their production. Theory of Non-classical States of Light describes the current status of the theory of nonclassical states of light including many new and important results as well as introductory material and the history of the subject. The authors concentrate on the most important types of nonclassical states, namely squeezed, even/odd ('Schrodinger cat') and binomial states, including their generalizations. However, a review of other types of nonclassical is also given in the introduction, and methods for generating nonclassical states on various processes of light-matter interaction, their phase-space description, and the time evolution of nonclassical states in these processes is presented in separate chapters. This contributed volume contains all of the necessary formulae and references required to gain a good understanding of the principles and current status of the field. It will provide a valuable information resource for advanced students and researchers in quantum physics.

Contents:Relationships Between q-Deformations, Typical Length Scales and Lower Measurability Bounds (E Papp)Description of Kerr States via Deformed Bosons (A I Solomon et al.)Quantum Mechanics on Phase Spaces ZN x ZN (J Tolar)Continuous Fuzzy Measurement of Energy: Realization and Application (J Audretsch)Decoherence and the Final Pointer Basis (M Castagnino & R Laura)On Hybrid Dynamics of the Copenhagen Dichotomic World (L Diósi)Storage and Read-Out of Quantum-State Information via Interference (M Freyberger et al.)Is There a Gravitational Collapse of the Wave-Packet? (H-J Schmidt)Operators and Maps Affiliated to EPR Channels (A Uhlmann)Reconstruction of Quantum States and Its Conceptual Implications (S Weigert)Geometric Formulation of Nonlinear Quantum Mechanics for Density Matrices (P Bóna)Fundamental Principles of Quantum Mechanics and Non(Linearity) (R Cirelli et al.)Nonlinear von Neumann-Type Equations (M Czachor et al.)Some Aspects of Nonlinearity and Gauge Transformation in Quantum Mechanics (G A Goldin)On a Theorem of Ashtekar and Lewandowski in the Mathematical Framework of Canonical Quantization in Quantum Gravity (H Baumgärtel)The Fuzzy (Super)Sphere and Field Theory (H Grosse & G Reiter)Quantum Fields Along Worldlines (M Keyl)Field Theory Revisited (C Piron)and other papers Readership: Mathematical physicists. Keywords:

The Białowieża workshops on Geometric Methods in Physics are among the most important meetings in the field. Every year some 80 to 100 participants from both mathematics and physics join to discuss new developments and to interchange ideas. This volume contains contributions by selected speakers at the XXX meeting in 2011 as well as additional review articles and shows that the workshop remains at the cutting edge of ongoing research. The 2011 workshop focussed on the works of the late Felix A. Berezin (1931–1980) on the occasion of his 80th anniversary as well as on Bogdan Mielnik and Stanisław Lech Woronowicz on their 75th and 70th birthday, respectively. The groundbreaking work of Berezin is discussed from today’s perspective by presenting an overview of his ideas and their impact on further developments. He was, among other fields, active in representation theory, general concepts of quantization and coherent states, supersymmetry and supermanifolds. Another focus lies on the accomplishments of Bogdan Mielnik and Stanisław Lech Woronowicz. Mielnik’s geometric approach to the description of quantum mixed states, the method of quantum state manipulation and their important implications for quantum computing and quantum entanglement are discussed as well as the intricacies of the quantum time operator. Woronowicz’ fruitful notion of a compact quantum group and related topics are also addressed.