"Which-path information" and partial polarization in single-photon interference experiments

It is shown that the degree of polarization of light, generated by superposition in a single-photon interference experiment, may depend on the indistinguishability of the photon-paths.Comment: 9 page

Synthesis and characterization of core-shell structure silica-coated Fe29.5Ni70.5 nanoparticles

In view of potential applications of magnetic particles in biomedicine and electromagnetic devices, we made use of the classical Stober method base-catalysed hydrolysis and condensation of tetraethoxysilane (TEOS) to encapsulate FeNi nanoparticles within a silica shell. An original stirring system under high power ultrasounds made possible to disperse the otherwise agglomerated particles. Sonication guaranteed particles to remain dispersed during the Stober synthesis and also improved the efficiency of the method. The coated particles are characterized by electron microscopy (TEM) and spectroscopy (EDX) showing a core-shell structure with a uniform layer of silica. Silica-coating does not affect the core magnetic properties. Indeed, all samples are ferromagnetic at 77 K and room temperature and the Curie point remains unchanged. Only the coercive force shows an unexpected non-monotonous dependence on silica layer thickness.Comment: Regular paper submited to international peer-reveiwed journa

Second Harmonic Generation for a Dilute Suspension of Coated Particles

We derive an expression for the effective second-harmonic coefficient of a dilute suspension of coated spherical particles. It is assumed that the coating material, but not the core or the host, has a nonlinear susceptibility for second-harmonic generation (SHG). The resulting compact expression shows the various factors affecting the effective SHG coefficient. The effective SHG per unit volume of nonlinear coating material is found to be greatly enhanced at certain frequencies, corresponding to the surface plasmon resonance of the coated particles. Similar expression is also derived for a dilute suspension of coated discs. For coating materials with third-harmonic (THG) coefficient, results for the effective THG coefficients are given for the cases of coated particles and coated discs.Comment: 11 pages, 3 figures; accepted for publication in Phys. Rev.

Quantum light depolarization: the phase-space perspective

Quantum light depolarization is handled through a master equation obtained by coupling dispersively the field to a randomly distributed atomic reservoir. This master equation is solved by transforming it into a quasiprobability distribution in phase space and the quasiclassical limit is investigated.Comment: 6 pages, no figures. Submitted for publicatio

Quantum polarization tomography of bright squeezed light

We reconstruct the polarization sector of a bright polarization squeezed beam starting from a complete set of Stokes measurements. Given the symmetry that underlies the polarization structure of quantum fields, we use the unique SU(2) Wigner distribution to represent states. In the limit of localized and bright states, the Wigner function can be approximated by an inverse three-dimensional Radon transform. We compare this direct reconstruction with the results of a maximum likelihood estimation, finding an excellent agreement.Comment: 15 pages, 5 figures. Contribution to New Journal of Physics, Focus Issue on Quantum Tomography. Comments welcom

The effectiveness of laser therapy on the management of chronic low back pain

yesBackground/Aim: Chronic low back pain (CLBP) is a global musculoskeletal challenge, resulting in pain and disability on individuals. Laser therapy can be used to treat CLBP. This review evaluates the effectiveness of laser therapy including high level laser therapy (HLLT) and low level laser therapy (LLLT) on CLBP in relation to pain or functional disability. Methods: The authors conducted a systematic review of randomised controlled trials (RCTs) and searched the Cochrane Library, MEDLINE, CINAHL, AMED and PEDro from their start to June 2015. All studies that met predetermined inclusion and exclusion criteria were appraised with The Cochrane Collaboration’s tool for assessing risk of bias and Critical Appraisal Skills Programme Tools in June, 2015. Findings: Six RCTs met the inclusion criteria: two RCTs reported significant improvement in pain and functional disability with the use of HLLT but with small sample size (n=103); one RCTs (n=61) reported significant improvement and three RCTs (n=215) reported insignificant improvement in pain and functional disability with the use of LLLT. Conclusion: On the strength of the evidence available HLLT and LLLT are not currently recommended to be replaced or be offered in addition to conventional treatment. Further rigorous research is required to confirm the potential use of laser therapy on individuals presenting with CLBP

Effective dissipative dynamics for polarized photons

In the framework of open quantum systems, the propagation of polarized photons can be effectively described using quantum dynamical semigroups. These extended time-evolutions induce irreversibility and dissipation. Planned, high sensitive experiments, both in the laboratory and in space, will be able to put stringent bounds on these non-standard effects.Comment: 15 pages, plain-TeX, no figure