We start this short note by remembering the beginnings of the Warsaw School of Quantum Optics, evidently stimulated by Iwo Białynicki-Birula at the Warsaw University, and then Centre for Theoretical Physics of Polish Academy of Sciences and Adam Kujawski and Zofia Białynicka-Birula at the Institute of Physics of Polish Academy of Sciences. In the theoretical approaches of the Warsaw School, quantum field theory was always present, and quantum optics was considered to be applied quantum electrodynamics. All of us who grew up in this fantastic community have carried and are still carrying the gospel to others. In particular, now quantum electrodynamics began her run on the red carpet of super intense laser–matter interactions, attosecond physics, and ultrafast laser physics in general. We will elaborate on the recent progress in this direction and on the open questions for future investigations. This paper celebrates the 90th birthday of Professor Iwo Białynicki-Birula, our quantum electrodynamics guru!
We start this short note by remembering the beginnings of the Warsaw School of Quantum Optics, evidently stimulated by Iwo Białynicki-Birula at the Warsaw University, and then Centre for Theoretical Physics of Polish Academy of Sciences and Adam Kujawski and Zofia Białynicka-Birula at the Institute of Physics of Polish Academy of Sciences. In the theoretical approaches of the Warsaw School, quantum field theory was always present, and quantum optics was considered to be applied quantum electrodynamics. All of us who grew up in this fantastic community have carried and are still carrying the gospel to others. In particular, now quantum electrodynamics began her run on the red carpet of super intense laser–matter interactions, attosecond physics, and ultrafast laser physics in general. We will elaborate on the recent progress in this direction and on the open questions for future investigations. This paper celebrates the 90th birthday of Professor Iwo Białynicki-Birula, our quantum electrodynamics guru!
Intense light-matter interaction largely relies on the use of high-power light sources, creating fields comparable to, or even stronger than, the field keeping the electrons bound in atoms. Under such conditions, the interaction induces highly nonlinear processes such as high harmonic generation, in which the low-frequency photons of a driving laser field are upconverted into higher-frequency photons. These processes have enabled numerous groundbreaking advances in atomic, molecular, and optical physics, and they form the foundation of attosecond science. Until recently, however, such processes were typically described using semi-classical approximations, since the quantum properties of the light field were not required to explain the observables. This has changed in the recent past. Ongoing theoretical and experimental advances show that fully quantized descriptions of intense light-matter interactions, which explicitly incorporate the quantum nature of the light field, open new avenues for both fundamental research and technological applications at the fully quantized level. These advances emerge from the convergence of quantum optics with strong-field physics and ultrafast science. Together, they have given rise to the field of quantum optics and quantum electrodynamics of strong-field processes.
Much of our present understanding of the microscopic world is based on quantum mechanics. The field owes much of its existence to the venerable science of optics, since the fundamental ideas on the nature of the interaction between light and matter lie at the roots of its origin. We have now reached one century of quantum mechanics. In contrast, the splendid blossoming of quantum optics began only after the comparatively recent invention of the laser. Since then, it has become an exciting and always expanding area at the cutting-edge of research, in part because theory and experiment are more closely connected in this field than any other. Moreover, the technological distance between fundamental studies and practical applications has always been very short in quantum optics. As a result, modern engineering is increasingly based on quantum rather than classical physics; we are facing a transition similar to the one society confronted 200 years ago, at the start of the Industrial Revolution. In parallel with this, the physics community is witnessing the recent and vigorous emergence of quantum information. It aims at exploring the physical foundations of information and at developing efficient methods for processing quantum information. The questions driving this field reveal a profound change in attitude towards fundamental aspects of quantum theory. The photon turns out to be a tool extremely well suited to exploring theoretical quantum information schemes and their experimental implementations. Mirroring this continued progress has been the growth and development of the series of annual Central European Workshops on Quantum Optics (CEWQO). The series started at the beginning of the 1990s, as rather small meetings of physicists from a few countries in central-eastern Europe. In two decades, the workshops have transformed into important events that reach well beyond the original rather restricted geographical limits. The history of CEWQOs can be found in the preface to the proceedings of the 15th CEWQO ( Physica Scripta 2009 T135 011005 ). The 18th edition of CEWQO (CEWQO11) was held in Madrid in 2011. There were about 250 participants, from practically every European country. Many colleagues from other continents also joined the event, including well-established researchers in the field. This is a clear demonstration that these meetings provide an excellent chance to hear about the latest results and new directions of research. The organization of CEWQO11 was carried out by a committee consisting of members active in this topic in Madrid. From Universidad Complutense, Alberto Galindo and Luis L Sánchez-Soto; from Universidad Autónoma, Jose Calleja and Carlos Tejedor; from Universidad Politécnica, Enrique Calleja; from Universidad Carlos III, Alberto Ibort; and from the National Research Council (CSIC), Juan León and Juan J García-Ripoll. Special thanks go to the Spanish Ministry for Science and Innovation, Universidad Complutense and the Quitemad Consortium for financial support. The proceedings of the 16th CEWQO held at the University of Turku, Finland and the 17th CEWQO held at the University of St Andrews, Scotland, UK are also available ( Physica Scripta 2010 T140 and Physica Scripta 2011 T143 ). The present Topical Issue is a collection of papers presented in Madrid; they represent an illustrative sample of the major achievements and trends in this area. In turn, they reflect the wide range of interests in this rapidly evolving field. Some collaborators from different scientific centres who could not, due to different reasons, come to Madrid, but participated in previous CEWQOs and plan to participate in future CEWQOs, also contributed to this issue. The papers are arranged alphabetically by the name of the first author. Special thanks goes to Roger Wäppling, the Managing Editor of Physica Scripta , and Graeme Watt, the Publisher, for the opportunity to publish CEWQO11. From a Physica Scripta Editorial Board meeting it was decided that Physica Scripta could offer a poster prize (200 euros + certificate) for young scientists (less than 30 years old) at the annual CEWQO conference. A panel of experts was formed to judge the posters which included Apostol Vourdas, University of Bradford, UK (Chairman), Alberto Ibort, University Carlos III of Madrid, Spain, Andrei Klimov, University of Guadalajara, Mexico, Margarita A Man'ko, P N Lebedev Physical Institute, Moscow, Russia and Antonino Messina, University of Palermo, Italy. The poster ''How can we check the uncertainty relation?'' by Vladimir Chernega, PhD student of the P N Lebedev Physical Institute, won the prize. The 19th Central European Workshop on Quantum Optics will be held in Sinaia, Romania on 2–6 July 2012. It will be chaired by Professor Aurelian Isar from the Horia Hulubei National Institute for Research and Development in Physics and Nuclear Engineering, Bucharest.
Intense laser-matter interactions are at the center of interest in research and technology since the development of high-power lasers.They have been widely used for fundamental studies in atomic, molecular, and optical physics, and they are at the core of attosecond physics and ultrafast optoelectronics.Although the majority of these studies have been successfully described using classical electromagnetic fields, recent investigations based on fully quantized approaches have shown that intense laser-atom interactions can be used for the generation of controllable high-photon-number entangled coherent states and coherent state superpositions.In this tutorial, we provide a comprehensive fully quantized description of intense laseratom interactions.We elaborate on the processes of high-harmonic generation, above-threshold ionization, and we discuss new phenomena that cannot be revealed within the context of semiclassical theories.We provide the description for conditioning the light field on different electronic processes, and their consequences for quantum state engineering of light.Finally, we discuss the extension of the approach to more complex materials, and the impact to quantum technologies for a new photonic platform composed of the symbiosis of attosecond physics and quantum information science.
Strong-laser-field physics is a research direction that relies on the use of high-power lasers and has led to fascinating achievements ranging from relativistic particle acceleration to attosecond science. On the other hand, quantum optics has been built on the use of low photon number sources and has opened the way for groundbreaking discoveries in quantum technology, advancing investigations ranging from fundamental tests of quantum theory to quantum information processing. Despite the tremendous progress, until recently these directions have remained disconnected. This is because the majority of the interactions in the strong-field limit have been successfully described by semi-classical approximations treating the electromagnetic field classically, as there was no need to include the quantum properties of the field to explain the observations. The link between strong-laser-field physics, quantum optics, and quantum information science has been developed in the recent past. Studies based on fully quantized and conditioning approaches have shown that intense laser-matter interactions can be used for the generation of controllable entangled and non-classical light states. These achievements open the way for a vast number of investigations stemming from the symbiosis of strong-laser-field physics, quantum optics, and quantum information science. Here, after an introduction to the fundamentals of these research directions, we report on the recent progress in the fully quantized description of intense laser-matter interaction and the methods that have been developed for the generation of non-classical light states and entangled states. Also, we discuss the future directions of non-classical light engineering using strong laser fields, and the potential applications in ultrafast and quantum information science.
The quantum nature of light enables potentially revolutionary communication technologies. A key to advancing this area of research is a clear understanding of the concepts of states, modes, fields, and photons. The concept of field modes carries over from classical optics, while the concept of state has to be considered carefully when treating light quantum mechanically. The term "photon" is an overloaded identifier in the sense that it is often used to refer to either a quantum particle or the state of a field. This overloading, often used without placing it in context, has the potential to obfuscate the physical processes that describe the reality we measure. We review the uses and relationships between these concepts using modern quantum optics theory, including the concept of a photon wave function, the modern history of which was moved forward in a groundbreaking paper in this journal by Iwo Białynicki-Birula, to whom this article is dedicated.
Among all the inventions that quantum physics has produced, the laser holds a particularly important place, both for the rich story of successive discoveries that led to its birth, and for the role it has played in fundamental and applied research. I recall here the lineage of theoretical discoveries and experiments that have marked this history, restricting myself to the contribution of lasers to blue sky science and leaving apart its well-known role in various domains of technology. This story started from advances in the old quantum theory, from Einstein’s theoretical description of stimulated emission to O. Stern’s experimental discovery of the spatial quantization of the electron spin. Nuclear magnetic resonance, atomic clocks, optical pumping, and masers followed and the pace of discoveries accelerated with the appearance of the laser in 1960. This extraordinary light source has since enabled breakthroughs in fundamental physics and opened up fields of research that could not even have been imagined at the time of its birth. I was fortunate to begin my career in physics at this crossroad of atomic physics and optics. I give in this article my personal view of the great adventures in fundamental research in which I participated as an actor or spectator, from the cooling and trapping of atoms by light, to the physics of quantum gases of bosons and fermions, the manipulation of individual quantum particles and quantum simulations. Many other areas of fundamental physics, which I will only mention briefly, owe their development to lasers and further advances are still to be expected in the years to come.