This year in October the Humboldt Foundation invited its award winners, fellows, alumni, top league scientists and young researchers to discuss problems and successes in quantum optics. It was the third Humboldt Award Winners‘ Forum held in Bonn from 9–12 October. The first one “Frontiers in Macromolecular and Material Science” was held in 2011, followed by “The New Desire for Metaphysics” the year after. This year, about 180 participants from all over the world attended the forum “Frontiers in Quantum Optics: Taming the World of Atoms and Photons – 100 Years after Niels Bohr” which took place at the Hotel Bristol and, partly, at the University of Bonn, Germany. Jürgen Fohrmann, rector of the university in Bonn, opened the conference with his welcome address, followed by Jürgen Nimptsch, the Lord Mayor of the City of Bonn, and Helmut Schwarz, President of the Alexander von Humboldt Foundation. The first keynote lecture was given by Serge Haroche (Collège de France, Paris) titled “Controlling photons in a box to explore the quantum world”. His talk outlined his Nobel Prize winning work and new developments (see Fig. 1).1 The next day (Thursday, 10), further welcome and introduction speeches were given by Enno Aufderheide, Secretary General of the Alexander von Humboldt Foundation, Wolfgang Sandner, Vice-President of the Deutsche Physikalische Gesellschaft, and Dieter Meschede from the University Bonn who organized the meeting. The forum was organized in four panels. The first one “Exploring the Quantum World with Atoms and Photons” was introduced and chaired by Jean-Michel Raimond. Howard J. Carmichael held a keynote lecture about 100 years of quantum jumps, outlining the history from Bohr and Einstein's A and B coefficients to the works by Haroche's group and beyond. Vahid Sandoghdar talked about the efficient coupling of single photons and single quantum emitters in a cavity-free way, Nir Davidson continued the session by talking about long coherence times in dense ultracold atomic ensembles, and Atac Imamoglu finished the session by outlining recent developments in solid-state quantum optics. The panel “Cold Atoms and Many Body Physics” was chaired by Wolfgang Ketterle who also introduced the topic in a brief presentation. Ketterle showed how physics is interconnected and that the study of cold atoms can indeed help solving problems in many-body (solid-state) physics. There is a quest for new materials, like high-temperature superconductors, new carbon-based materials (e.g. nanotubes or graphene) or materials revealing colossal magnetoresistance, to name just a few. There will be more materials needed in the future. To newly discover or to further understand these materials “we like to use paradigmatic models”, he said, “some sort of atomic ‘legos’ that help us understand complex systems”. We are now in a process of quantum “engineering” that will most likely guide future progress in the field. The following lectures further outlined this vision. Georgii V. Shlyapnikov talked about many-body physics of quantum gases in disorder. Of special interest was his discussion about work based on D.M. Basko, I.L. Aleiner, B.L. Altshuler (the AAH model) in which fluid–insulator transitions of disordered quantum gases were discussed. In these systems a surprising effect can occur. Shlyapnikov said: “Imagine you boil a pot of water and then discover that you got ice cubes as a result”, i.e. phase transitions can occur that are unique and do not appear in other systems or materials. Massimo Inguscio continued the session with a discussion about ultracold fermions and novel one-dimensional matter, and Michael Köhl talked about photonic coupling of atoms and solid-state quantum systems, asking the question “Can we make different quantum systems communicate with each other?” – a theme that will keep many scientists busy over the next few years or decades. Finally, Tilman Pfau showed the potential of using electrons of Rydberg atoms to probe Bose–Einstein condensates (BEC). As he showed, the electrons of Rydberg atoms with very high principal quantum numbers (e.g. around n = 100 to 200) can enclose up to several thousand atoms of a Bose–Einstein condensate – a remarkable achievement which allows the investigation of electron–phonon scattering in the BEC. After a full day of science William A. Kinderman gave a lecture on Ludwig van Beethoven's 1823 composed Diabelli variations and completed his presentation with a first-class performance of the piano sonata in C minor, Opus 111, at the Beethovenhaus in Bonn. The next day (Friday, 11) started with the panel “Quantum Information Science”, which was introduced and chaired by Michael Fleischhauer. Arno Rauschenbeutel talked about the possibilities to trap and investigate ions using an optical nanofiber, a technique that has potential as a quantum memory and processing device for quantum computing. Jian-Wei Pan discussed recent experimental progress in quantum manipulation with photons and cold atoms, specifically in quantum information processing (QIP). He showed that linear system equations of the form ; can be solved faster using QIP (with O(log(N)) steps) than in a classical way (with O(N) steps), but that the scalability of QIP is still a challenge as it requires quantum repeaters and quantum memories. He also showed the latest achievements in long-range free-space quantum communication of around 100 km in China and other places and noted that the next step would be to cover a 1200-km distance via satellite. The ultimate aim is to enable and set up large-scale, long-range quantum communication networks. Andrea Alberti discussed transport phenomena in quantum systems. Using quantum walks with neutral atoms as an example he showed that classical and quantum systems differ strongly in their behavior. The last session contribution was by David DiVincenzo talking about prospects for superconducting qubits including some outlook for “Moore's law” of coherence times, and surface code error correction using resonators or cavities. Elisabeth Giacobino then introduced the panel “Precision Measurements and Hot Topics”, with keynote lecturer Jun Ye talking about probing exotic quantum matter (e.g. many-body quantum spin dynamics in which quantum fluctuations become correlated) with clock precision. Edward A. Hinds discussed how cold atoms can be used to test fundamental physics, and Gerald Gabrielse continued in this direction with his talk about measured and calculated properties of elementary particles. For example: Is there an electron electric dipole moment? According to the current standard model it is nearly nonexistent (around ). Gabrielse and his coworkers want to challenge this by going beyond the current experimental limit of by one or more orders of magnitude. A positive result would have tremendous effect on the standard model and could help to decide on recent predictions by supersymmetric and technicolor models. Quantum optomechanics on various scales, from nano- to macromechanics was discussed by Markus Aspelmeyer. He also showed that this research field has potential to make contributions at the absolute limit of the physical realm, testing fundamental physical aspects where quantum and space–time (i.e. gravity) aspects become relevant. In the evening, Hans Bachor (Australian National University, Wamboin) gave the dinner speech, or what he called “the after soup” speech as he was placed between the starter and the main course. Among other things, Bachor recalled how science was done in the early times of quantum mechanics and pointed to the central role of personal relationships and friendships among scientists. Bohr was put forward as a memorable example who brought forward many of the central ideas of quantum mechanics by walking and discussing matters with his colleagues, like Heisenberg and Einstein. It is this deep, sometimes controversial, but continuous thinking that enables us to solve sheer insurmountable problems jointly as an interactive science community. The Alexander von Humboldt (AvH) foundation sets great value on promoting excellent scientists, but it does not stop with a one-time support. It goes beyond the usual sponsorship by continued fostering of its award winners, fellows and alumni. It is the networking aspect that makes the foundation a key player in Germany's scientific landscape and unique among international science founders. Steffan Mehlich (AvH representative) emphasized that the family aspect of the Alexander von Humboldt foundation is key to its success and helps strengthen the links within the network. Consequently, the forum did not end with the scientific talks but continued with a cultural program. Here, the participants could visit the castle “Burg Satzvey”, the Radio Telescope Effelsberg at Bad Münstereifel-Effelsberg (Max Planck Institute for Radio Astronomy), and the winery “Kloster Marienthal” (Bad Neuenahr), thus getting into closer contact with each other. Helmut Schwarz formulated it at the beginning of the meeting: “Science is made by individuals, not by projects”. In the end it needs both – individuals and projects – but the meeting showed that without a strong focus on the researcher as a person there will be no progress. This meeting was in the right spirit to bring together outstanding individuals and to make them think and work together.
This year in October the Humboldt Foundation invited its award winners, fellows, alumni, top league scientists and young researchers to discuss problems and successes in quantum optics. It was the third Humboldt Award Winners‘ Forum held in Bonn from 9–12 October. The first one “Frontiers in Macromolecular and Material Science” was held in 2011, followed by “The New Desire for Metaphysics” the year after. This year, about 180 participants from all over the world attended the forum “Frontiers in Quantum Optics: Taming the World of Atoms and Photons – 100 Years after Niels Bohr” which took place at the Hotel Bristol and, partly, at the University of Bonn, Germany. Jürgen Fohrmann, rector of the university in Bonn, opened the conference with his welcome address, followed by Jürgen Nimptsch, the Lord Mayor of the City of Bonn, and Helmut Schwarz, President of the Alexander von Humboldt Foundation. The first keynote lecture was given by Serge Haroche (Collège de France, Paris) titled “Controlling photons in a box to explore the quantum world”. His talk outlined his Nobel Prize winning work and new developments (see Fig. 1).1 The next day (Thursday, 10), further welcome and introduction speeches were given by Enno Aufderheide, Secretary General of the Alexander von Humboldt Foundation, Wolfgang Sandner, Vice-President of the Deutsche Physikalische Gesellschaft, and Dieter Meschede from the University Bonn who organized the meeting. The forum was organized in four panels. The first one “Exploring the Quantum World with Atoms and Photons” was introduced and chaired by Jean-Michel Raimond. Howard J. Carmichael held a keynote lecture about 100 years of quantum jumps, outlining the history from Bohr and Einstein's A and B coefficients to the works by Haroche's group and beyond. Vahid Sandoghdar talked about the efficient coupling of single photons and single quantum emitters in a cavity-free way, Nir Davidson continued the session by talking about long coherence times in dense ultracold atomic ensembles, and Atac Imamoglu finished the session by outlining recent developments in solid-state quantum optics. The panel “Cold Atoms and Many Body Physics” was chaired by Wolfgang Ketterle who also introduced the topic in a brief presentation. Ketterle showed how physics is interconnected and that the study of cold atoms can indeed help solving problems in many-body (solid-state) physics. There is a quest for new materials, like high-temperature superconductors, new carbon-based materials (e.g. nanotubes or graphene) or materials revealing colossal magnetoresistance, to name just a few. There will be more materials needed in the future. To newly discover or to further understand these materials “we like to use paradigmatic models”, he said, “some sort of atomic ‘legos’ that help us understand complex systems”. We are now in a process of quantum “engineering” that will most likely guide future progress in the field. The following lectures further outlined this vision. Georgii V. Shlyapnikov talked about many-body physics of quantum gases in disorder. Of special interest was his discussion about work based on D.M. Basko, I.L. Aleiner, B.L. Altshuler (the AAH model) in which fluid–insulator transitions of disordered quantum gases were discussed. In these systems a surprising effect can occur. Shlyapnikov said: “Imagine you boil a pot of water and then discover that you got ice cubes as a result”, i.e. phase transitions can occur that are unique and do not appear in other systems or materials. Massimo Inguscio continued the session with a discussion about ultracold fermions and novel one-dimensional matter, and Michael Köhl talked about photonic coupling of atoms and solid-state quantum systems, asking the question “Can we make different quantum systems communicate with each other?” – a theme that will keep many scientists busy over the next few years or decades. Finally, Tilman Pfau showed the potential of using electrons of Rydberg atoms to probe Bose–Einstein condensates (BEC). As he showed, the electrons of Rydberg atoms with very high principal quantum numbers (e.g. around n = 100 to 200) can enclose up to several thousand atoms of a Bose–Einstein condensate – a remarkable achievement which allows the investigation of electron–phonon scattering in the BEC. After a full day of science William A. Kinderman gave a lecture on Ludwig van Beethoven's 1823 composed Diabelli variations and completed his presentation with a first-class performance of the piano sonata in C minor, Opus 111, at the Beethovenhaus in Bonn. The next day (Friday, 11) started with the panel “Quantum Information Science”, which was introduced and chaired by Michael Fleischhauer. Arno Rauschenbeutel talked about the possibilities to trap and investigate ions using an optical nanofiber, a technique that has potential as a quantum memory and processing device for quantum computing. Jian-Wei Pan discussed recent experimental progress in quantum manipulation with photons and cold atoms, specifically in quantum information processing (QIP). He showed that linear system equations of the form ; can be solved faster using QIP (with O(log(N)) steps) than in a classical way (with O(N) steps), but that the scalability of QIP is still a challenge as it requires quantum repeaters and quantum memories. He also showed the latest achievements in long-range free-space quantum communication of around 100 km in China and other places and noted that the next step would be to cover a 1200-km distance via satellite. The ultimate aim is to enable and set up large-scale, long-range quantum communication networks. Andrea Alberti discussed transport phenomena in quantum systems. Using quantum walks with neutral atoms as an example he showed that classical and quantum systems differ strongly in their behavior. The last session contribution was by David DiVincenzo talking about prospects for superconducting qubits including some outlook for “Moore's law” of coherence times, and surface code error correction using resonators or cavities. Elisabeth Giacobino then introduced the panel “Precision Measurements and Hot Topics”, with keynote lecturer Jun Ye talking about probing exotic quantum matter (e.g. many-body quantum spin dynamics in which quantum fluctuations become correlated) with clock precision. Edward A. Hinds discussed how cold atoms can be used to test fundamental physics, and Gerald Gabrielse continued in this direction with his talk about measured and calculated properties of elementary particles. For example: Is there an electron electric dipole moment? According to the current standard model it is nearly nonexistent (around ). Gabrielse and his coworkers want to challenge this by going beyond the current experimental limit of by one or more orders of magnitude. A positive result would have tremendous effect on the standard model and could help to decide on recent predictions by supersymmetric and technicolor models. Quantum optomechanics on various scales, from nano- to macromechanics was discussed by Markus Aspelmeyer. He also showed that this research field has potential to make contributions at the absolute limit of the physical realm, testing fundamental physical aspects where quantum and space–time (i.e. gravity) aspects become relevant. In the evening, Hans Bachor (Australian National University, Wamboin) gave the dinner speech, or what he called “the after soup” speech as he was placed between the starter and the main course. Among other things, Bachor recalled how science was done in the early times of quantum mechanics and pointed to the central role of personal relationships and friendships among scientists. Bohr was put forward as a memorable example who brought forward many of the central ideas of quantum mechanics by walking and discussing matters with his colleagues, like Heisenberg and Einstein. It is this deep, sometimes controversial, but continuous thinking that enables us to solve sheer insurmountable problems jointly as an interactive science community. The Alexander von Humboldt (AvH) foundation sets great value on promoting excellent scientists, but it does not stop with a one-time support. It goes beyond the usual sponsorship by continued fostering of its award winners, fellows and alumni. It is the networking aspect that makes the foundation a key player in Germany's scientific landscape and unique among international science founders. Steffan Mehlich (AvH representative) emphasized that the family aspect of the Alexander von Humboldt foundation is key to its success and helps strengthen the links within the network. Consequently, the forum did not end with the scientific talks but continued with a cultural program. Here, the participants could visit the castle “Burg Satzvey”, the Radio Telescope Effelsberg at Bad Münstereifel-Effelsberg (Max Planck Institute for Radio Astronomy), and the winery “Kloster Marienthal” (Bad Neuenahr), thus getting into closer contact with each other. Helmut Schwarz formulated it at the beginning of the meeting: “Science is made by individuals, not by projects”. In the end it needs both – individuals and projects – but the meeting showed that without a strong focus on the researcher as a person there will be no progress. This meeting was in the right spirit to bring together outstanding individuals and to make them think and work together.
Quantum many-body systems, as they appear in different branches of physics and chemistry, are very hard to simulate. The number of parameters defining their quantum states grows exponentially with the number of constituents. This prevents us from exploring and investigating relevant problems involving relatively small numbers of subsystems even with the help of the most powerful supercomputers. Richard Feynman already noticed this difficulty back in 1981 when he wrote his visionary paper “Simulating Physics with Computers” [Int. J. Theor. Phys. 21:6/7, 467 (1982)]. There, he proposed to use quantum systems (as opposed to classical computers) to perform the simulation and in this way to circumvent the need to store and compute a colossal number of parameters, necessary to describe the pertaining superpositions. What was a visionary idea at that time has become a very active field of research in the last few years. The extraordinary progress of both theoretical and experimental research in quantum physics allows us now to tame, control, and manipulate various quantum systems with unprecedented precision. Laser, magnetic, electronic and other technologies enable us to arrange quantum subsystems in different geometries, modify their interactions, and detect them. This allows us to engineer Hamiltonians and emulate systems displaying some of the most intriguing quantum phenomena. This tremendous progress is, to a large extent, due to the pioneering work of many researchers during the last twenty to thirty years. Here, the investigations of basic phenomena with one or few atoms or photons were of particular impact. The degree of control achieved in the experiments has enabled the observation of mind-boggling quantum effects, related to the superposition principle or to entangled states, and their disappearance due to decoherence. In fact, the 2012 Nobel Prize has been awarded to two scientists, S. Haroche and D. Wineland, for such ground-breaking experiments. Such experiments, often in combination with laser cooling of atoms or ions and Bose-Einstein condensation, have formed one of the pillars on which the field of quantum simulations is being established. Quantum simulations with cold atoms, either in magnetic traps or in optical lattices, with trapped ions, with photons, with superconducting devices, with quantum dots, etc., have been theoretically proposed and experimentally considered by many researchers. Most of the proposals so far deal with problems in condensed matter physics that are either difficult to tackle with modern supercomputers or are difficult to observe in solid state systems. This has established a very close link between different disciplines, like atomic, molecular, and optical (AMO) physics, and condensed matter physics. Although some of the experiments are still in their infancy, and a lot of research is still needed, the extraordinary progress made in all these research areas during the last few years makes us feel confident that in the not too distant future quantum simulators will provide a key tool to investigate many-body quantum systems. Furthermore, we also expect that quantum simulators will help quantum physicists to establish new and fruitful links to other scientific communities, like high-energy physics or quantum chemistry. The present special issue contains various review papers as well as research papers on quantum simulations. It starts out with two papers written by last year's Nobel Prize winners describing their foundational work (Wineland, p. 739 and Haroche, p. 763). The issue continues with three thorough, invited review papers covering different topics on quantum simulations. The first one reviews recent theoretical proposals to use cold atoms in optical lattices to simulate lattice gauge theories of the sort that appear in high-energy physics (U.-J. Wiese, p. 783). The second covers both theoretical proposals and experimental demonstrations of cold-atom systems to simulate the physics of matter in the presence of gauge fields, displaying so-called topological phenomena, which so far have only been observed in solid-state systems (I. Spielman, p. 794). The third one contains an extensive overview and new proposals to perform a broad range of quantum simulations using quantum dot systems (P. Barthelmy et al., p. 813). The issue also includes six original papers with a variety of theoretical proposals as well as the introduction of novel theoretical techniques related to the field of quantum simulation. The field of quantum simulations is just starting, but we are confident that it will soon generate an even larger plethora of new ideas and discoveries, trigger interdisciplinary research, and lead us to the adventure of describing and understanding the quantum world. We hope that this special issue will help future researchers in such an exciting adventure. Rainer Blatt received his PhD degree in physics from the University of Mainz in 1981. As a postdoctoral fellow he worked on atomic beam cooling in Boulder, CO and later as a research assistant in Hamburg with single trapped ions. In 1995 he accepted a chair in experimental physics at the University of Innsbruck working on quantum information processing with trapped ions. Since 2003 he is also scientific director at the Institute for Quantum Optics and Quantum Information (IQOQI) of the Austrian Academy of Sciences. Immanuel Bloch received his PhD degree in physics from the Ludwig Maximilians University of Munich in 2000. As a junior group leader, he continued in Munich starting his work on ultracold quantum gases in optical lattices. In 2008 he was appointed scientific director of the newly founded division on Quantum Many-Body Systems at the Max Planck Institute of Quantum Optics. Since 2009 he also holds a chair in quantum optics at the Ludwig-Maximilians University of Munich. Ignacio Cirac received his PhD degree in physics from the Universidad Complutense de Madrid in 1991. He was professor at the Universities of Castilla-La Mancha and Innsbruck from 1991–1996 and 1996–2001, respectively. In 2001 he joined the Max-Planck Institute of Quantum Optics, where he leads the Theory Division. His current research interests include quantum information theory and quantum optics. Peter Zoller obtained his doctorate from the University of Innsbruck in 1977. He was Max Kade Fellow at the University of Southern California from 1978/79, and was JILA visiting Fellow 1981/82 and 1988. In 1990 he became JILA Fellow and professor of physics at the University of Colorado. At the end of 1994, he accepted a chair at the University of Innsbruck, where he has worked ever since. Since 2003, he has also held the position of Scientific Director at the Institute for Quantum Optics and Quantum Information (IQOQI) of the Austrian Academy of Sciences.
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.
A year passed-by full of exciting physics and new discoveries. One of the major announcements in 2013 was the discovery of the Higgs boson at CERN 1. ATLAS and CMS experiments confirmed that a new particle has been found which is compatible with the Higgs boson. In the same year, the Nobel Prize in physics was awarded to François Englert and Peter W. Higgs “for the theoretical discovery of a mechanism that contributes to our understanding of the origin of mass of subatomic particles…” 2. Although the prize went to two theory pioneers it is clear that this success was a result of major efforts of thousands of people, including experimentalists, engineers as well as people working in administration, logistic and funding. A truly Big Science enterprise. Annalen der Physik congratulates all people involved for this feast of human curiosity, endurance and the untiring will to understand nature. In addition to this, understanding fundamental physical laws can also be brought forward on a low energy scale which marked a major theme in Annalen der Physik last year, see our (double) special issue on “Precision Experiments and Fundamental Physics at Low Energies” edited by Klaus Blaum, Holger Müller, and Nathal Severijns3, 4. Other topics were of interest, too. Recently, and most likely inspired by the seminal work from Nobel laureates Serge Haroche 5 and David Wineland 6, our guest editors and advisory board members Rainer Blatt, Immanuel Bloch, Ignacio Cirac, and Peter Zoller organized the special issue “Quantum Simulation” which also presents the Nobel lectures of the afore mentioned prize winners 7. In this context I would like to point to the work of S. Schmidt and J. Koch “Circuit QED lattices – Towards quantum simulation with superconducting circuits” earlier last year 8 and to M. Schlosshauer, J. Kofler and A. Zeilinger's discussion on “The interpretation of quantum mechanics: from disagreement to consensus?” 9. Yet, there were more aspects in physics that seemed worth to be brought forward. Peter Hommelhoff, Matthias Kling, and Mark Stockman organized a special issue with invited contributions in the field of “Ultrafast Phenomena on the Nanoscale” 10, including intensely discussed problems in the field like high-harmonic generation 11-14. What else is out there? For 2014, Annalen der Physik has announced to publish focus issues on three major topics to catch up with recent research efforts in some of the most challenging and promising branches in our field. One of the most puzzling and controversially discussed questions concerns the destiny of our universe. Richard Battye, Ariel Goobar, and Jochen Weller organize the special issue “The Accelerating Universe” (submission deadline March 17, 2014). Invitations to participate are still open and can be viewed at www.ann-phys.org. This special issue complements the issue on “Dark Matter” by Matthias Bartelmann and Volker Springel 15 from 2012 with highlight articles from Lars Bergstrom 16, Carlos S. Frenk and Simon D.M. White 17 and many more. Another topic will be covered by Jack Harris, Peter Rabl and Albert Schliesser, focusing on “Quantum and Hybrid Mechanical Systems – From Fundamentals to Applications” (submission deadline May 2, 2014). This issue, too, adds nicely to our previous efforts to publish more articles in this field, see for example Pierre Meystre's overview article “A short walk through quantum optomechanics” 18. Further submissions are welcome! Finally, Francisco Guinea, Misha I. Katsnelson, and Tim Wehling will organize the issue “Two-dimensional Materials: Electronic Structure and Many-Body Effects” (submission deadline May 1, 2014). As the guest editors said these new materials “hold the promise for novel devices with designed electronic properties” thus being today's subject of basic research and tomorrow's everyday technology. For further details, please visit our homepage. In this current issue we present some interesting overview works in the fields of quantum optics (G. Feve et al. page 1) and two-dimensional spectroscopy (G. Scholes et al. page 31), as well as novel research work by P. Kinsler and M. McCall on spacetime transformation theory (page 51) and J. E. Hirsch's work on superconductivity and diamagnetism (page 63). R. L. Hall et al. report on Nodal theorems for the Dirac equation (page 79), C. Henkel and V. E. Mkrtchian describe the Casimir effect (page 87), A. Kolovsky discusses bosonic and fermionic carriers in one- and two-dimensional lattices (page 102), and Y. Fu et al. report on light absorbing by meta-nanorings (page 112). Enjoy reading Annalen der Physik!
We observe non destructively photons trapped in a high Q cavity, generate quantum fields in “Schrödinger cat” like states and study their decoherence. Application of these studies to the processing of quantum information will be discussed. 150-word Biography: Serge Haroche, born in 1944 in Casablanca, graduated from Ecole Normale Supérieure (ENS), receiving his doctorate from Paris VI University in 1971. After a post-doctoral visit to Stanford University (1972-73), he became full professor at Paris VI University in 1975, a position he held until 2001, when he was appointed Professor at Collège de France. Since September 2012, he is the President (Administrateur) of this institution. Haroche’s research has mostly taken place in the laboratory Kastler Brossel at ENS. His main research activities have been in quantum optics and quantum information science. He has made important contributions to Cavity Quantum Electrodynamics (Cavity QED), the domain of quantum optics which studies the behaviour of atoms interacting strongly with the field confined in a high-Q cavity. An atom-photon system isolated from the outside world by metallic walls realizes a very simple experimental model which Serge Haroche and his team have used to test fundamental aspects of quantum physics such as state superposition, entanglement, complementarity and decoherence. Serge Haroche has received many prizes and awards, culminating in the 2012 Nobel Prize in physics, shared with David Wineland. Article not available.
18 What are these methods, why are they jointly recognized? The key endeavour in the last century of quantum physics has been the exploration of the coupling between matter and electromagnetic radiation. For a long time, the available experimental techniques were limited to a large number of atoms and a very large number of photons. It was only in thought experiments that one envisioned the manipulation of well-controlled individual quantum systems, dreamed of experimenting with a single atom or a single photon. For instance, Einstein and Bohr once imagined weighing a photon trapped forever in a box, covered by perfect mirrors. These gedankenexperiments and their “ridiculous consequences”, as Schrodinger once stated, played a considerable role in the genesis of quantum physics interpretation. The technical progress made these experiments possible. One can now realize some of the founding fathers' thought experiments. D. Wineland's ion traps and S. Haroche's Cavity Quantum Electrodynamics (CQED) have pioneered this domain, which is now thriving worldwide. The 2012 Nobel prize in physics has been awarded jointly to Serge Haroche (College de France and Ecole Normale Superieure) and David Wineland (National Institute for Standards and Technology, USA) “for ground-breaking experimental methods that enable measuring and manipulation of individual quantum systems”. l Michel Brune1, Jean-Michel Raimond1, Claude Cohen-Tannoudji 1,2 DOI: 10.1051/epn/2012601 l 1 Laboratoire Kastler Brossel, ENS, CNRS, UMPC Paris 6, 24 rue Lhomond, 75005 Paris, France l 2 College de France, 11 place Marcelin Berthelot, 75005 Paris, France Nobel 2012: Trapped ions and photons
The development of quantum optics was part and parcel of the formation of modern physics following the fundamental work of Max Planck and Albert Einstein, which gave rise to quantum mechanics. The possibility of working with pure quantum objects, like single atoms and single photons, has turned quantum optics into the main tool for testing the fundamentals of quantum physics. Thus, despite a long history, quantum optics nowadays remains an extremely important branch of physics. It represents a natural base for the development of advanced technologies, like quantum information processing and quantum computing. Previous Central European Workshops on Quantum Optics (CEWQO) took place in Palermo (2007), Vienna (2006), Ankara (2005), Trieste (2004), Rostock (2003), Szeged (2002), Prague (2001), Balatonfüred (2000), Olomouc (1999), Prague (1997), Budmerice (1995, 1996), Budapest (1994) and Bratislava (1993). Those meetings offered excellent opportunities for the exchange of knowledge and ideas between leading scientists and young researchers in quantum optics, foundations of quantum mechanics, cavity quantum electrodynamics, photonics, atom optics, condensed matter optics, and quantum informatics, etc. The collaborative spirit and tradition of CEWQO were a great inspiration and help to the Institute of Physics, Belgrade, and the Serbian Academy of Sciences and Arts, as the organizers of CEWQO 2008. The 16th CEWQO will take place in 2009 in Turku, Finland, and the 17th CEWQO will be organized in 2010 in St Andrews, United Kingdom. The 15th CEWQO was organized under the auspices and support of the Ministry of Science of the Republic of Serbia, the Serbian Physical Society, the European Physical Society with sponsorship from the University of Belgrade, the Central European Initiative, the FP6 Program of the European Commission under INCO project QUPOM No 026322, the FP7 Program of the European Commission under project NANOCHARM, Europhysics Letters (EPL), The European Physical Journal (EPJ), and John Wiley and Sons.