Ultrahigh-quality factor resonant dielectric metasurfaces based on hollow nanocuboids

In this work, a dielectric metasurface consisting of hollow dielectric nanocuboids, with ultrahigh quality factor, is theoretically proposed and demonstrated. The variation of the hole size of the cuboid allows for the tuning of the resonant anapole mode in the nanoparticles. The metasurface is designed to operate in two complementary modes, namely electromagnetically induced transparency and narrowband selective reflection. Thanks to the non-radiative nature of the anapole resonances, the minimal absorption losses of the dielectric materials, and the near-field coupling among the metasurface nanoparticles, a very high quality factor of =2.5×106 is achieved. The resonators are characterized by a simple bulk geometry and the subwavelength dimensions of the metasurface permit operation in the non-diffractive regime. The high quality factors and strong energy confinement of the proposed devices open new avenues of research on light-matter interactions, which may find direct applications, e.g., in non-linear devices, biological sensors, laser cavities, and optical communications.Research and Development Program through the Comunidad de Madrid (SINFOTON S2013/MIT-2790); Ministerio de Economia y Competitividad of Spain (TEC2013-47342-C2-2-R); mobility programs of Carlos III University and "Jose Castillejo" of the Ministerio de Educacion, Cultura y Deporte of Spain

Author Correction: Multifunctional light beam control device by stimuli-responsive liquid crystal micro-grating structures

Correction to: Scientific Reports https://doi.org/10.1038/s41598-020-70783-8, published online 14 August 2020 This Article contains a typographical error in the Acknowledgements section. “the Ministerio de Economía y Competitividad of Spain (TEC2013-47342-C2-2-R)” should read: "the Ministerio de Economía y Competitividad of Spain (TEC2016-77242-C3-1-R)"This work was supported by the Comunidad de Madrid and FEDER Program (S2018/NMT-4326), the Ministerio de Economía y Competitividad of Spain (TEC2013-47342-C2-2-R and TEC2016-76021-C2-2-R), the FEDER/Ministerio de Ciencia, Innovación y Universidades and Agencia Estatal de Investigación (RTC2017-6321-1, PID2019-109072RB-C31 and PID2019-107270RB-C21). The authors also acknowledge the support by the Ministry of National Defense of Poland (GBMON/13-995/2018/WAT), Military University of Technology (Grant no. 23-895)

Cylindrical and Powell liquid crystal lenses with positive-negative optical power

We demonstrate a technique to engineer cylindrical and Powell liquid crystal lenses with positive or negative optical power. The device is based on two indium-tin-oxide electrode combs and a microstructured voltage transmission electrode. The technique features the advantages of a multielectrode lens, albeit using a single lithographic step and only two voltage sources. Extensive control of the phase profile across the device active area is demonstrated, achieving both positive and negative optical power. The lens aperture is not constrained by the geometrical parameters and can be scaled to larger values.This work was supported in part by the Comunidad de Madrid and FEDER Program under Grant S2018/NMT-4326, in part by the Ministerio de Economía y Competitividad of Spain under Grant TEC2013-47342-C2-2-R and Grant TEC2016-76021-C2-2-R, in part by the FEDER/Ministerio de Ciencia, Innovación y Universidades and Agencia Estatal de Investigación under Grant RTC2017-6321-1, Grant PID2019-109072RB-C31, and Grant PID2019-107270RB-C21, in part by the Ministry of National Defense of Poland under Grant GBMON/13-995/2018/WAT, and in part by the Military University of Technology under Grant 23-895

Positive-negative tunable liquid crystal lenses based on a microstructured transmission line

In this work, a novel technique to create positive-negative tunable liquid crystal lenses is proposed and experimentally demonstrated. This structure is based on two main elements, a transmission line acting as a voltage divider and concentric electrodes that distribute the voltage homogeneously across the active area. This proposal avoids all disadvantages of previous techniques, involving much simpler fabrication process (a single lithographic step) and voltage control (one or two sources). In addition, low voltage signals are required. Lenses with switchable positive and negative focal lengths and a simple, low voltage control are demonstrated. Moreover, by using this technique other optical devices could be engineered, e.g. axicons, Powell lenses, cylindrical lenses, Fresnel lenses, beam steerers, optical vortex generators, etc. For this reason, the proposed technique could open new venues of research in optical phase modulation based on liquid crystal materials.This work was supported by Comunidad de Madrid and FEDER Program (S2018/NMT-4326), the Ministerio de Economía y Competitividad of Spain (TEC2016-77242-C3-1-R and TEC2016-76021-C2-2-R), the FEDER/ Ministerio de Ciencia, Innovación y Universidades and Agencia Estatal de Investigación (RTC2017-6321-1). Also, the Ministry of National Defense of Poland (GBMON/13-995/2018/WAT)

Non-supersymmetric heterotic model building

We investigate orbifold and smooth Calabi-Yau compactifications of the non-supersymmetric heterotic SO(16)xSO(16) string. We focus on such Calabi-Yau backgrounds in order to recycle commonly employed techniques, like index theorems and cohomology theory, to determine both the fermionic and bosonic 4D spectra. We argue that the N=0 theory never leads to tachyons on smooth Calabi-Yaus in the large volume approximation. As twisted tachyons may arise on certain singular orbifolds, we conjecture that such tachyonic states are lifted in the full blow-up. We perform model searches on selected orbifold geometries. In particular, we construct an explicit example of a Standard Model-like theory with three generations and a single Higgs field.Comment: 1+30 pages latex, 11 tables; v2: references and minor revisions added, matches version published in JHE

Charmed states and flavour symmetry breaking

Extending the SU(3) flavour symmetry breaking expansion from up, down and strange sea quark masses to partially quenched valence quark masses allows an extrapolation to the charm quark mass. This approach leads to a determination of charmed quark hadron masses and decay constants. We describe our recent progress and give preliminary results in particular with regard to the recently discovered doubly charmed baryon by the LHCb Collaboration.Comment: 8 pages, 9 figures, talk presented at the 35th International Symposium on Lattice Field Theory, 18-24 June 2017, Granada, Spai

Canine leishmaniasis: the key points for qPCR result interpretation

Background: Diagnosis and follow up of CanL is difficult since the range of clinical signs is varied and seroprevalence is high in endemic areas. The aims of this study were: i) demonstrate the advantages of Leishmania qPCR to diagnose and control CanL and highlight its prognostic value and ii) propose guidelines for tissue selection and infection monitoring. Findings: This study included 710 dogs living in an endemic area of leishmaniasis. Forty percent (285/710) exhibited clinical signs consistent with CanL. Infection was detected in 36.3% (258/710) of the dogs of which 4.5% (32/710) were detected by qPCR, 16.2% (115/710) detected by ELISA and 15.6% (111/710) tested positive for both tests. Only 17.9% (127/710) of the dogs were classified sick (affected) with CanL. All symptomatic dogs with medium or high ELISA titers were qPCR-positive in blood samples. All dogs with inconclusive or low ELISA results with high or medium qPCR parasitemia values developed the disease. Seventy one percent of asymptomatic ELISA-positive dogs confirmed by qPCR (medium to high parasitemia) developed the disease. Bone marrow or lymph node aspirate should be selected to ensure the absence of the parasite in asymptomatic dogs: 100-1,000 parasites/ml in bone marrow are detectable in blood, whereas lower parasite loads are usually negative. Almost 10% of negative samples in blood were positive in conjunctival swabs. Conclusions: Because qPCR allows parasite quantification, it is an effective tool to confirm a diagnosis of CanL in (i) cases of inconclusive ELISA results, (ii) when the dog has not yet seroconverted, or (iii) for treatment monitoring

Measurement of the cross-section and charge asymmetry of WW bosons produced in proton-proton collisions at s=8\sqrt{s}=8 TeV with the ATLAS detector

This paper presents measurements of the $W^+ \rightarrow \mu^+\nu$ and $W^- \rightarrow \mu^-\nu$ cross-sections and the associated charge asymmetry as a function of the absolute pseudorapidity of the decay muon. The data were collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS experiment at the LHC and correspond to a total integrated luminosity of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the 1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured with an uncertainty between 0.002 and 0.003. The results are compared with predictions based on next-to-next-to-leading-order calculations with various parton distribution functions and have the sensitivity to discriminate between them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables, submitted to EPJC. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13

Search for squarks and gluinos in events with isolated leptons, jets and missing transverse momentum at s√=8 TeV with the ATLAS detector

The results of a search for supersymmetry in final states containing at least one isolated lepton (electron or muon), jets and large missing transverse momentum with the ATLAS detector at the Large Hadron Collider are reported. The search is based on proton-proton collision data at a centre-of-mass energy s√=8 TeV collected in 2012, corresponding to an integrated luminosity of 20 fb−1. No significant excess above the Standard Model expectation is observed. Limits are set on supersymmetric particle masses for various supersymmetric models. Depending on the model, the search excludes gluino masses up to 1.32 TeV and squark masses up to 840 GeV. Limits are also set on the parameters of a minimal universal extra dimension model, excluding a compactification radius of 1/R c = 950 GeV for a cut-off scale times radius (ΛR c) of approximately 30

Constraints on the χ_(c1) versus χ_(c2) polarizations in proton-proton collisions at √s = 8 TeV

The polarizations of promptly produced χ_(c1) and χ_(c2) mesons are studied using data collected by the CMS experiment at the LHC, in proton-proton collisions at √s=8  TeV. The χ_c states are reconstructed via their radiative decays χ_c → J/ψγ, with the photons being measured through conversions to e⁺e⁻, which allows the two states to be well resolved. The polarizations are measured in the helicity frame, through the analysis of the χ_(c2) to χ_(c1) yield ratio as a function of the polar or azimuthal angle of the positive muon emitted in the J/ψ → μ⁺μ⁻ decay, in three bins of J/ψ transverse momentum. While no differences are seen between the two states in terms of azimuthal decay angle distributions, they are observed to have significantly different polar anisotropies. The measurement favors a scenario where at least one of the two states is strongly polarized along the helicity quantization axis, in agreement with nonrelativistic quantum chromodynamics predictions. This is the first measurement of significantly polarized quarkonia produced at high transverse momentum