Single-photon generation and simultaneous observation of wave and particle properties

We describe an experiment that generates single photons on demand and measures properties accounted to both particle- and wave-like features of light. The measurement is performed by exploiting data that are sampled simultaneously in a single experimental run.Comment: The following article has been submitted to Proceedings of "Foundations of probability and physics-3", Vaxjo, Sweden 2004. After it is published, it will be found at http://proceedings.aip.org/ . 1 Reference was added in version

The Perfect Atom: Bound States of Supersymmetric Quantum Electrodynamics

We study hydrogen-like atoms in N=1 supersymmetric quantum electrodynamics with an electronic and a muonic family. These atoms are bound states of an anti-muon and an electron or their superpartners. The exchange of a photino converts different bound states into each other. We determine the energy eigenstates and calculate the spectrum to fourth order in the fine structure constant. A difference between these perfect atoms and non-supersymmetric ones is the absence of hyperfine structure. We organize the eigenstates into super multiplets of the underlying symmetry algebra.Comment: 30 pages, 2 figures. v2: mistake associated with gauge choice fixed, references added. v3: comment about super-positronium added, published versio

Feature fusion reveals slow and fast visual memories

Although the visual system can achieve a coarse classification of its inputs in a relatively short time, the synthesis of qualia-rich and detailed percepts can take substantially more time. If these prolonged computations were to take place in a retinotopic space, moving objects would generate extensive smear. However, under normal viewing conditions, moving objects appear relatively sharp and clear, suggesting that a substantial part of visual short-term memory takes place at a nonretinotopic locus. By using a retinotopic feature fusion and a nonretinotopic feature attribution paradigm, we provide evidence for a relatively fast retinotopic buffer and a substantially slower nonretinotopic memory. We present a simple model that can account for the dynamics of these complementary memory processes. Taken together, our results indicate that the visual system can accomplish temporal integration of information while avoiding smear by breaking off sensory memory into fast and slow components that are implemented in retinotopic and nonretinotopic loci, respectively

'Finding beauty' in French rural prisons. How prison officers operate rurality

The literature on rural criminology and rural prisons has so far essentially focused on debunking myths about rurality and rural crimes, and on the economic and social impacts of building prisons in rural areas. Typically, such rural prisons are recent. Conversely, due to its long history, France's rural prisons have in some cases been built during the 19th century within former convents from the Middle Ages or monasteries confiscated from the church during the 1789 Revolution. Missing from this literature, therefore, is, on the one hand, a focus on historic rural prison settings and, on the other hand, attention to individuals and professionals who work there. This paper focuses on a high security prison set in a middle-ages abbey in the middle of nature. In our interviews with its prison officers (POs) we used appreciative inquiry in order to better uncover the positive dimensions of rurality. We find that rurality is used to reinforce safety and the 'right distance' with prisoners, and to better cut off from the prison environment when they finish their shift. We also find that POs are bound by strong (rural) family ties that in turn contribute to their professional identity and values, and to their feelings of safety

A folded-sandwich polarization-entangled two-color photon pair source with large tuning capability for applications in hybrid quantum architectures

We demonstrate a two-color entangled pho ton pair source which can be adapted easily to a wide range of wavelengths combinations. A Fresnel rhomb as a geometrical quarter-wave plate and a versatile combination of compensation crystals are key components of the source. Entanglement of two photons at the Cs D1 line (894.3 nm) and at the telecom O-band (1313.1 nm) with a fidelity of $F = 0.753 \pm 0.021$ is demonstrated and improvements of the setup are discussed

Mediation centrality in adversarial policy networks

Conflict resolution often involves mediators who understand the issues central to both sides of an argument. Mediators in complex networks represent nodes that are connected to other key nodes in opposing subgraphs. Here we introduce a new metric, mediation centrality, for iden- tifying good mediators in adversarial policy networks, such as the connections between indi- viduals and their reasons for and against the support of controversial topics (e.g., state-financed abortion). Using a process-based account of reason mediation we construct bipartite adversar- ial policy networks and show how mediation defined over subgraph projections constrained to reasons representing opposing sides can be used to produce a measure of mediation centrality that is superior to centrality computed on the full network. We then empirically illustrate and test mediation centrality in a “policy fluency task,” where participants generated reasons for or against eight controversial policy issues (state-subsidized abortion, bank bailouts, forced CO2 reduction, cannabis legalization, shortened naturalization, surrogate motherhood legalization, public smoking ban, and euthanasia legalization). We discuss how mediation centrality can be extended to adversarial policy networks with more than two positions and to other centrality measures

Complexity, Age, and Building Preference

The authors explore the role of complexity in the relation between building age and preference. Age was assessed as a categorical (via stimulus selection) and a continuous (via ratings of 64 color slides of urban buildings) variable. In either case, the authors replicated earlier research in showing that modern buildings were preferred over older buildings when building maintenance was not controlled, but when it was controlled, the relation reversed, and the older buildings were better liked. However, when a composite-rating measure of complexity was introduced, a somewhat different pattern emerged. Complexity interacted with rated age. The nature of the interaction was that throughout most of the range of complexity scores, age was negatively related to preference, but at the higher end of the complexity range, there was no relation between age and preference. Other findings: Buildings with visible entrances were preferred to those without, and distant views were preferred over near views

Danger, Mystery, and Environmental Preference

The possibility of a connection among high mystery, perceived danger, and depressed preference for certain categories of environments was investigated. Past research had suggested that urban alleys and narrow canyons would exhibit such a pattern. Comparison categories, chosen to be high in mystery and low in perceived danger, were urban and non-urban nature (that is, field-and-forest settings within urban or non-urban environments), respectively. Preference ratings were obtained for settings from each of the four categories. The settings were also rated by independent raters for six predictor variables: mystery, physical danger, social danger, shadow, nature, and vertical depth. The major findings were that danger was a negative predictor of preference and mystery was a positive predictor. There was no evidence that high mystery was involved in depressed preference ratings for any of the environmental categories investigated. The distinction between physical and social danger proved useful, with only social danger related (negatively) to preference