The German image

Abstract

This important book is not a technical history, nor is it ‘sociological’ in any scientific sense; its main thrust is rather in the realm of ‘the history of ideas’ and ‘the history of taste’, and it is thus intimately concerned with human values and attitudes. In this way, and because human nature transceinds national boundaries with conspicuous ease, Fritz Kempe's work is not ‘merely’ about Germany, but about photography and people in general. Without constraining system and without claims to exhaustive coverage, the book manages to get at the spirit and core of relationships by discussing 24 topics, which range from local history (‘Bremen, Wannover, Kassel’) to episodic accounts (‘On the secret magic of the hruman image’). That is its special charm, and also its lasting testament, because photography is really too complex a field to permit a stereotype presentation, if the finer nuances of the human response are to be given their due. If anything is lacking—but it would be chnrlisll to expect a single volume to cover every base—it is a more extensive discussion of the daguerreotype's influence on German painters.     

High-sensitivity Diffraction-compensated Moiré Deflectometry

Abstract

The spatial resolution and angular sensitivity of conventional moiré deflectometry are known to obey a conjugate relationship reminiscent of the uncertainty principle so that one cannot be improved without deteriorating the other. This paper looks at the origin of this relationship and suggests ways by which this ‘uncertainty principle’ can be violated. It is shown that a ‘projection’ of the grating which is free from diffraction effects and which, at the same time, contains the deflection information amplified by the ‘optical lever’ distance D between the gratings can be formed if the diffracted beams of order + 1 and ? 1 are separated from other orders and are recombined in certain ways. As a result, the angular sensitivity, which depends on the ratio of the pitch d of the grating to the distance D between the two gratings, can be improved without losing the spatial resolution by multiple diffraction orders. One of the diffraction compensation schemes is experimentally illustrated. It is shown that the ‘uncertainty product’ is improved by more than two orders of magnitude.     

Can the kicked top be realized?

Abstract

Collections of identical two-level atoms can give rise to (quantum) chaotic behaviour if non-resonantly coupled to a resonator mode and periodically driven. Observation of such chaos would require a new generation of experiments on microwave superradiance, or optical variants thereof which would exploit the strong coupling characteristic of very small cavities. Similarly, collections of identical three-level atoms non-resonantly coupled to two cavity modes could provide ‘SU(3) laboratories’, capable of realizing the semiclassical and classical limits of SU(3) dynamics, both integrable and chaotic. Some of the more interesting modes of behaviour of such systems are discussed.     

Entangling atoms and ions in dissipative environments

Abstract

Quantum information processing rests on our ability to manipulate quantum superpositions through coherent unitary transformations, and to establish entanglement between constituent quantum components of the processor. The quantum information processor (a linear ion trap, or a cavity confining the radiation field for example) exists in a dissipative environment. We discuss ways in which entanglement can be established within such dissipative environments. We can even make use of a strong interaction of the system with its environment to produce entanglement in a controlled way.     

The inside–outside contact search algorithm for finite element analysis

A new contact search algorithm (Inside–Outside Algorithm) for the sheet forming simulation has been developed and implemented in the dynamic explicit FE code: ‘DYNAMIC’. The inside–outside algorithm is derived based on the feature of the inside–outside status of a nodal ‘mesh normal vector’ in respect to a surface segment for the judgment of the contact of FE nodes with the tool surface. This new algorithm includes local search, local track and penetration calculation processes. Almost no additional CPU time is required for the local search process, because the calculations for both global and local search are combined. Moreover, the problems of conventional contact searching algorithms, such as iterations for local search and the deadzone problem, are resolved. Therefore, the quick, robust contact searching and accurate evaluation of penetration have been achieved. The numerical results show that the new contact searching algorithm is more cost effective and robust than conventional ones. © 1997 John Wiley & Sons, Ltd.     

Three-photon W-state

Abstract

Multiphoton entanglement is the basis of many quantum communication schemes, quantum cryptographic protocols, and fundamental tests of quantum theory. For entangled three-qubit states it has been shown that there are two inequivalent classes of states, under stochastic local operations and classical communications. The classes are represented by the GHZ- and W-state. The GHZ-state has been used to prove Bell's theorem without inequality. Contrary to the GHZ-state, the W-state shows high robustness of entanglement against photon loss. Here we show the first experimental results on the observation of the polarization entangled three-photon W-state from spontaneous parametric down-conversion.     

Einstein localization in entangled light scattering

Abstract

We discuss Einstein-Podolsky-Rosen (EPR)-type entanglement in two-particle break-up, using Raman scattering with atom recoil as an example. The Schmidt number K is used as a measure of entanglement and the conditions to acquire high entanglement are obtained. We also illustrate the EPR conditional uncertainty in a situation where Δx Δp reaches a value much smaller than the Heisenberg limit.     

Daguerre's Demonstrations in 1839 at the Palais d'Orsay

Abstract

RDW: Researching some aspects of the course of events in Paris in 1839 regarding the daguerreotype, I realized that the place where Daguerre first demonstrated his process in public had not been reported in the past with any consistency. Had such a situation arisen because various interpretations of the original French could be involved? For example, the word ‘hotel’, having a different meaning in French than in English, would be an obvious reason why a French address could be rendered in different ways in English publications.     

Frequency shift attack on ‘plug-and-play’ quantum key distribution systems

Many imperfections in a practical quantum key distribution (QKD) system have been exploited by an eavesdropper (Eve) to attack the system. However, most of these attacks will introduce perturbations to the system while collecting information about the key. For example, the phase-remapping attack [Phys. Rev. A2007,75, 032314], in which Eve performs time shift on the signal pulse from the constant acting range of the phase modulation voltage to its rising edge to introduce an imperfection, results in an quantum bit error rate (QBER) of 14.6%, which is too high and will be discovered by careful users. In this paper, a frequency shift (FS) attack on ‘plug-and-play’ QKD systems with phase-coding BB84 protocol is proposed, in which Eve introduces an imperfection by the same method as she used in the phase-remapping attack. The most novel advantage of our FS attack is that Eve can get full information without introducing detectable QBER, which is more deceptive than the phase-remapping attack.     

IoT-based networking for humanoid robots

Abstract

In this paper, a new network communication approach, named real-time network (RTNET), is designed and implemented for humanoid robots. The proposed five network objects – alarm, condition, message, mail, and file are used to represent the task and priority of the communication data. Compared to the existing protocols, the network scheduling mechanism of RTNET arranges, more efficiently, the priority and flow control of the five network communication objects to meet real-time requirements for the limited bandwidth of the local area network. RTNET can be further integrated with other protocols, such as EtherCAT or controller area networks (CAN Bus) for local control systems, e.g. robot arms, to improve the communication mechanism. The RTNET can also be used over Ethernet to connect each subsystem and to exchange information among those systems. Also, an Internet of things (IoT) network structure based on RTNET is proposed in this paper. The information of each subsystems is collected through RTNET and users can access all components in the IoT network. In this paper, the concept of RTNET is presented and RTNET has been implemented on a National Taiwan University (NTU) humanoid robot control system with CAN Bus.     

A magneto-active scaffold for stimulation of bone growth

Abstract

Creating ‘smart’ biomedical devices with the potential for controlled actuation in vivo has been a long-standing scientific pursuit in therapeutic medicine. The present work focuses on a bone regeneration scaffold based on ferromagnetic fibres designed to induce in vivo modelling of in-growing periprosthetic bone by the application of an external magnetic field of clinical magnitude. We present the conceptual basis of such a ‘magneto-active scaffold’, the properties of prime interest and how these properties can be controlled.     

Obituary

Abstract

This handsome book is a superb introduction to the history of photography in Japan as well as a catalogue of The History of Japanese Photography exhibition held at the Museum of Fine Arts in Houston and the Cleveland Museum of Art (2003). The over-sized (12 x 10 inches) volume contains 207 beautifully reproduced photographic plates, seven chapters discussing the history of photography in Japan from 1848 until 2000, and a helpful series of appendices. The latter includes the ‘Exhibition Checklist’, a ‘Chronology’, ‘Artist Profiles’, listings of ‘Major Photography Clubs and Associations’ and ‘Major Photography Magazines’, a ‘Selected Bibliography’ and an ‘Index’. For those interested in a well written, informative and visually stimulating introduction to the subject, this is the book to consult.     

Bell's inequality tests: from photons to B-mesons

We analyse the recent claim that a violation of a Bell's inequality has been observed in the B-meson system [A. Go, J. Mod. Opt. 51 991 (2004)]. The results of this experiment are a convincing proof of quantum entanglement in B-meson pairs similar to that shown by polarization entangled photon pairs. However, we conclude that the tested inequality is not a genuine Bell's inequality and thus cannot discriminate between quantum mechanics and local realistic approaches.     

Between orientalist clichés and images of modernization

Abstract

In contemporary writing about nineteenth-century photography of the Middle East it has become almost a cliche to describe many of these images as ‘Orientalist’-that is, reflecting or propagating a system of representation that creates an essentialized difference between the ‘Orient’ and the ‘West’. Most of these scholars draw on Edward Said's influential book Orientalism, which traces how Europe manufactured an imaginary Orient through literary works and the social sciences.¹ For example, Nissan N. Perez writes in his book Focus East: Early Photography in the Near East (1839–1885) that ‘Literature, painting, and photography fit the real Orient into the imaginary or mental mold existing in the Westerner's mind .... These attitudes are mirrored in many of the photographs taken during this time [the nineteenth century] ... Either staged or carefully selected from a large array of possibilities, they became living visual documents to prove an imaginary reality’. ²     

Active Optics

Abstract

A system of ‘active optics’ control for the optical imagery of astronomical telescopes has been under development in the European Southern Observatory for about ten years. Its first application will be in the 3·5 m New Technology Telescope (NTT) scheduled for operation in 1988. A model test with a thin 1 m mirror (aspect ratio 56) has given remarkably successful results which will be reported in Part II of this paper. Part I gives a complete presentation of the theoretical principles of this technique of active optics and its scope of application. The subject is treated from the viewpoint of the temporal band-pass of error sources, ‘active optics’ being concerned with the low-frequency band-pass. The high-frequency band-pass (‘adaptive optics’) is principally concerned with atmospheric correction and is only briefly referred to for comparison. ‘Active optics’ correction of the low-band-pass system errors should bring major improvements in image quality together with a large cost reduction. While its impact on ground-based telescopes seems beyond doubt, the most important application should be in space projects where permanent diffraction-limited performance should be possible with much relaxed tolerances.     

Atapuerca: evolution of scientific collaboration in an emergent large-scale research infrastructure

We study the evolution of scientific collaboration at Atapuerca’s archaeological complex along its emergence as a large-scale research infrastructure (LSRI). Using bibliometric and fieldwork data, we build and analyze co-authorship networks corresponding to the period 1992–2011. The analysis of such structures reveals a stable core of scholars with a long experience in Atapuerca’s fieldwork, which would control coauthorship-related information flows, and a tree-like periphery mostly populated by ‘external’ researchers. Interestingly, this scenario corresponds to the idea of a Equipo de Investigación de Atapuerca, originally envisioned by Atapuerca’s first director 30 years ago. These results have important systemic implications, both in terms of resilience of co-authorship structures and of ‘oriented’ or ‘guided’ self-organized network growth. Taking into account the scientific relevance of LSRIs, we expect a growing number of quantitative studies addressing collaboration among scholars in this sort of facilities in general and, particularly, emergent phenomena like the Atapuerca case.     

The ‘Peccavi’ Photographs

Abstract

Among the holdings of the Asiatic Library of Bombay, there is a major album entitled Sind Photographs, which has become known to the initiated under the title ‘Peccavi Photographs’, in memory of a delicious political pun¹. All the photographs are portraits, with captions neatly inscribed. None is signed, but one bears the imprint ‘Photo by Capt. Houghton’, which was sufficient to provide researchers with an important clue as to their origin.     

Lewis Hine

Abstract

‘I'm afraid, Mr Hine, that you haven't the broad sociological background required,’ said a distinguished adviser when Lewis W. Hine announced his decision to give up teaching at the Ethical Culture School and set up as a ‘social’ photographer. ‘Nonsense,’ retorted Arthur Kellogg, ‘it's wonderful to find a photographer who has any sociological background’.     

The Reception of Albert Renger-Patzsch's Die Welt ist schön

Abstract

No history of photography or publication on the photography of the 1920s fails to mention the photo-book Die Welt ist schön. Regarded as a ‘manifesto of the revival of Realism,’¹ and hailed as the ‘bible’ of Neue Sachlichkeit photography,² ‘hardly any other book has influenced a generation of photographers to the same great extent and with such long-lasting effects as this volume‘.³ It was the book's tide in particular that was received like a catchword and influenced the reception of this photographic volume: ‘The tide became symbolic for an attitude of Neue Sachlichkeit to the world and the book was acknowledged as the ideal volume of Neue Sachlichkeit photography’.⁴ Hitherto in the history of the book's reception, this opinion has been restricted primarily to the reference to Walter Benjamin's well-known negative critique of 1931.⁵ Amongst the multitude of reviews of Die Welt ist schon, it is Benjamin's assessment which is most frequendy cited in the literature. That Benjamin was able to neglect explicidy mentioning Renger-Patzsch's name and to refer merely to the tide of the book can be interpreted as proof of the great fame of this photographic author. In fact, Die Welt ist schön had by this time been reviewed in nearly all leading cultural magazines and daily newspapers and evaluated as an exemplary volume of a modem, neusachliche photography. For critics such as Benjamin, however, the tide was synonymous with a new, sterile ‘l’art pour l'art' photography which manipulated reality and denied social contexts. But to confine negative criticism of Die Welt ist schön to the political left and its praise to a more conservative attitude is too simple a model as becomes apparent when all of the reviews are taken into consideration. Karl With's attempt to summarize the contradictions of this picture book may be cited here: ‘Ein seltsames Buch!} (A strange book!). Exciting in its busding abundance, as well as in its silence’.⁶     

Commutation Rules and Eigenvalues of Spin and Orbital Angular Momentum of Radiation Fields

Abstract

We investigate the separation of the total angular momentum J of the electromagnetic field into a ‘spin’ part S and an ‘orbital’ part L. We show that both ‘spin’ and ‘orbital’ angular momentum are observables. However, the transversality of the radiation field affects the commutation relations for the associated quantum operators. This implies that neither S nor L are angular momentum operators. Moreover their eigenvalues are not discrete. We construct field modes such that each mode excitation (photon) is in a simultaneous eigenstate of S _z and L _z. We consider the interaction of such a photon with an atom and the resulting effect on the internal and external part of the atomic angular momentum.