Two-photon interference between disparate sources for quantum networking

Quantum networks involve entanglement sharing between multiple users. Ideally, any two users would be able to connect regardless of the type of photon source they employ, provided they fulfill the requirements for two-photon interference. From a theoretical perspective, photons coming from different origins can interfere with a perfect visibility, provided they are made indistinguishable in all degrees of freedom. Previous experimental demonstrations of such a scenario have been limited to photon wavelengths below 900 nm, unsuitable for long distance communication, and suffered from low interference visibility. We report two-photon interference using two disparate heralded single photon sources, which involve different nonlinear effects, operating in the telecom wavelength range. The measured visibility of the two-photon interference is 80+/-4%, which paves the way to hybrid universal quantum networks

First test on Photonic Crystal Fiber potential for broadband interferometry

International audienceThe Photonic Crystal Fibers (PCFs) are microstructured waveguides currently developed in the frame of metrology, non-linear optics or coherent tomography. PCF studies are mainly focused on the improvement of dispersion property and wide spectral single-mode operating domain. Consequently, in the astronomical context, this kind of fiber is a good candidate to design a fiber linked version of stellar interferometer for aperture synthesis. In this paper, we study the potential of these fibers taking advantage of the wide spectral single-mode operation. We propose an experimental setup acting as a two-beam interferometer using PCFs to measure fringes contrasts at four different wavelengths (670nm, 980nm, 1328nm and 1543nm) corresponding to R, I, J and H astronomical bands with the same couple of PCFs. For this purpose, we implement for the first time a piezoelectric PCF optical path modulator

Birefringence analysis of multilayer leaky cladding optical fibre

We analyse a multilayer leaky cladding (MLC) fibre using the finite element method and study the effect of the MLC on the bending loss and birefringence of two types of structures: (i) a circular core large-mode-area structure and (ii) an elliptical-small-core structure. In a large-mode-area structure, we verify that the multilayer leaky cladding strongly discriminates against higher order modes to achieve single-mode operation, the fibre shows negligible birefringence, and the bending loss of the fibre is low for bending radii larger than 10 cm. In the elliptical-small-core structure we show that the MLC reduces the birefringence of the fibre. This prevents the structure from becoming birefringent in case of any departures from circular geometry. The study should be useful in the designs of MLC fibres for various applications including high power amplifiers, gain flattening of fibre amplifiers and dispersion compensation.Comment: 18 page

Single cell genomics-based analysis of gene content and expression of prophages in a diffuse-flow deep-sea hydrothermal system

© The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Labonte, J. M., Pachiadaki, M., Fergusson, E., McNichol, J., Grosche, A., Gulmann, L. K., Vetriani, C., Sievert, S. M., & Stepanauskas, R. Single cell genomics-based analysis of gene content and expression of prophages in a diffuse-flow deep-sea hydrothermal system. Frontiers in Microbiology, 10, (2019): 1262, doi:10.3389/fmicb.2019.01262.Phage–host interactions likely play a major role in the composition and functioning of many microbiomes, yet remain poorly understood. Here, we employed single cell genomics to investigate phage–host interactions in a diffuse-flow, low-temperature hydrothermal vent that may be reflective of a broadly distributed biosphere in the subseafloor. We identified putative prophages in 13 of 126 sequenced single amplified genomes (SAGs), with no evidence for lytic infections, which is in stark contrast to findings in the surface ocean. Most were distantly related to known prophages, while their hosts included bacterial phyla Campylobacterota, Bacteroidetes, Chlorobi, Proteobacteria, Lentisphaerae, Spirochaetes, and Thermotogae. Our results suggest the predominance of lysogeny over lytic interaction in diffuse-flow, deep-sea hydrothermal vents, despite the high activity of the dominant Campylobacteria that would favor lytic infections. We show that some of the identified lysogens have co-evolved with their host over geological time scales and that their genes are transcribed in the environment. Functional annotations of lysogeny-related genes suggest involvement in horizontal gene transfer enabling host’s protection against toxic metals and antibacterial compounds.This work was supported by the U.S. National Science Foundation’s Dimensions of Biodiversity Program [OCE-1136488 (to RS), OCE-1136727 (to SMS) and OCE-1136451 (to CV)], as well as DEB-1441717 and OCE-1335810 (to RS), and the DOE JGI CSP project 1477

Risk-Taking and Risk of Falls in Community-Dwelling Older Adults: A Scoping Review

Background: Risk-taking behaviors have emerged as a target for fall prevention. However, the risk-taking concepts are complex, and several approaches exist to identify risk-taking behaviors. In addition, studies of fall-related risk-taking behaviors have not yet been systematically evaluated. Methods: This scoping review was conducted in accordance with Joanna Briggs Institute’s methodology for scoping reviews. Six electronic databases were searched to identify studies published between 2000 and 2020. Studies were included in our review if they were conducted on community-dwelling older adults (≥ 65 years) and discussed fallrelated risk-taking behaviors. Data extraction and analyses were completed using a table developed a priori by the research team. Results: Self-reported behaviors using qualitative methodology were the most common approach to identifying risktaking behaviors in community-dwelling older adults. Generally, older adults are aware of their fall risk and tend to adopt behaviours to help mitigate it. However, older adults also described moments of deliberate risk-taking driven by the potential benefits of this behavior. Factors associated with risk-taking include an individual’s abilities, personal values, and physical and social environment. Conclusion: This review demonstrated that fall-related risk-taking behaviors are a highly individualized concept influenced by a number of factors. Therefore, future research should evaluate how risk appraisal, risk attitudes, and risk propensity predict fall-related risk-taking behaviors in community-dwelling older adults

On Passion and Sports Fans:A Look at Football

The purpose of the present research was to test the applicability of the Dualistic Model of Passion (Vallerand et al., 2003) to being a sport (football) fan. The model posits that passion is a strong inclination toward an activity that individuals like (or even love), that they value, and in which they invest time and energy. Furthermore, two types of passion are proposed: harmonious and obsessive passion. While obsessive passion entails an uncontrollable urge to engage in the passionate activity, harmonious passion entails a sense of volition while engaging in the activity. Finally, the model posits that harmonious passion leads to more adaptive outcomes than obsessive passion. Three studies provided support for this dualistic conceptualization of passion. Study 1 showed that harmonious passion was positively associated with adaptive behaviours (e.g., celebrate the team’s victory), while obsessive passion was rather positively associated with maladaptive behaviours (e.g., to risk losing one’s employment to go to the team’s game). Study 2 used a short Passion Scale and showed that harmonious passion was positively related to the positive affective life of fans during the 2006 FIFA World Cup, psychological health (self-esteem and life satisfaction), and public displays of adaptive behaviours (e.g., celebrating one’s team victory in the streets), while obsessive passion was predictive of maladaptive affective life (e.g., hating opposing team’s fans) and behaviours (e.g., mocking the opposing team’s fans). Finally, Study 3 examined the role of obsessive passion as a predictor of partner’s conflict that in turn undermined partner’s relationship satisfaction. Overall, the present results provided support for the Dualistic Model of Passion. The conceptual and applied implications of the findings are discussed

Relativistic wave equations for interacting massive particles with arbitrary half-intreger spins

New formulation of relativistic wave equations (RWE) for massive particles with arbitrary half-integer spins s interacting with external electromagnetic fields are proposed. They are based on wave functions which are irreducible tensors of rank $n ($n=s-\frac12$) antisymmetric w.r.t. n pairs of indices, whose components are bispinors. The form of RWE is straightforward and free of inconsistencies associated with the other approaches to equations describing interacting higher spin particles