Explore the vast range of titles available.

Strong coupling of monolayer metal dichalcogenide semiconductors with light offers encouraging prospects for realistic exciton devices at room temperature. However, the nature of this coupling depends extremely sensitively on the optical confinement and the orientation of electronic dipoles and fields. Here, we show how plasmon strong coupling can be achieved in compact, robust, and easily assembled gold nano-gap resonators at room temperature. We prove that strong-coupling is impossible with monolayers due to the large exciton coherence size, but resolve clear anti-crossings for greater than 7 layer devices with Rabi splittings exceeding 135 meV. We show that such structures improve on prospects for nonlinear exciton functionalities by at least 10 4 , while retaining quantum efficiencies above 50%, and demonstrate evidence for superlinear light emission. Two-dimensional materials offer the prospect of excitonic devices operating at room-temperature. Here, Kleemann et al. demonstrate that by tuning the number of WSe 2 layers in a nanoparticle-on-mirror geometry, room-temperature plasmon strong-coupling can be achieved with large Rabi splittings.

Energy relaxation of photo-excited charge carriers is of significant fundamental interest and crucial for the performance of monolayer transition metal dichalcogenides in optoelectronics. The primary stages of carrier relaxation affect a plethora of subsequent physical mechanisms. Here we measure light scattering and emission in tungsten diselenide monolayers close to the laser excitation energy (down to ~0.6 meV). We reveal a series of periodic maxima in the hot photoluminescence intensity, stemming from energy states higher than the A-exciton state. We find a period ~15 meV for 7 peaks below (Stokes) and 5 peaks above (anti-Stokes) the laser excitation energy, with a strong temperature dependence. These are assigned to phonon cascades, whereby carriers undergo phonon-induced transitions between real states above the free-carrier gap with a probability of radiative recombination at each step. We infer that intermediate states in the conduction band at the Λ-valley of the Brillouin zone participate in the cascade process of tungsten diselenide monolayers. This provides a fundamental understanding of the first stages of carrier–phonon interaction, useful for optoelectronic applications of layered semiconductors. The primary stages of carrier relaxation in atomically thin transition metal dichalcogenides are hardly accessible due to their fast timescales. Here, the authors measure the first stages of carrier–phonon interaction in monolayer WSe 2 via a series of periodic maxima in the hot photoluminescence intensity, assigned to phonon cascades.

We report on a measurement of Spin Density Matrix Elements (SDMEs) in hard exclusive [Formula omitted] meson muoproduction at COMPASS using 160 GeV/c polarised [Formula omitted] and [Formula omitted] beams impinging on a liquid hydrogen target. The measurement covers the kinematic range 5.0 GeV/ [Formula omitted] [Formula omitted] 17.0 GeV/ [Formula omitted], 1.0 (GeV/c) [Formula omitted] [Formula omitted] 10.0 (GeV/c) [Formula omitted] and 0.01 (GeV/c) [Formula omitted] [Formula omitted] 0.5 (GeV/c) [Formula omitted]. Here, W denotes the mass of the final hadronic system, [Formula omitted] the virtuality of the exchanged photon, and [Formula omitted] the transverse momentum of the [Formula omitted] meson with respect to the virtual-photon direction. The measured non-zero SDMEs for the transitions of transversely polarised virtual photons to longitudinally polarised vector mesons ( [Formula omitted]) indicate a violation of s-channel helicity conservation. Additionally, we observe a dominant contribution of natural-parity-exchange transitions and a very small contribution of unnatural-parity-exchange transitions, which is compatible with zero within experimental uncertainties. The results provide important input for modelling Generalised Parton Distributions (GPDs). In particular, they may allow one to evaluate in a model-dependent way the role of parton helicity-flip GPDs in exclusive [Formula omitted] production.

Interlayer excitons in layered materials constitute a novel platform to study many-body phenomena arising from long-range interactions between quantum particles. Long-lived excitons are required to achieve high particle densities, to mediate thermalisation, and to allow for spatially and temporally correlated phases. Additionally, the ability to confine them in periodic arrays is key to building a solid-state analogue to atoms in optical lattices. Here, we demonstrate interlayer excitons with lifetime approaching 0.2 ms in a layered-material heterostructure made from WS 2 and WSe 2 monolayers. We show that interlayer excitons can be localised in an array using a nano-patterned substrate. These confined excitons exhibit microsecond-lifetime, enhanced emission rate, and optical selection rules inherited from the host material. The combination of a permanent dipole, deterministic spatial confinement and long lifetime places interlayer excitons in a regime that satisfies one of the requirements for simulating quantum Ising models in optically resolvable lattices. Excitons are quasiparticles consisting of an electron-hole pair and can be used to study many-body phenomenon. Here, the authors demonstrate on-demand quantum confinement of long-lived interlayer excitons in WS 2 /WSe 2 heterostructures deposited on nanopatterned substrates.

Background BCD-022 is a trastuzumab biosimilar which was shown to be equivalent to reference trastuzumab in a wide panel of physicochemical studies as well as preclinical studies in vitro and in vivo. International multicenter phase III clinical trial was conducted to comparatively assess efficacy and safety of BCD-022 and reference trastuzumab in combination with paclitaxel used as the therapy of metastatic HER2(+) breast cancer. Pharmacokinetics and immunogenicity were also studied. Methods Patients with no previous treatment for metastatic HER2(+) breast cancer were randomly assigned 1:1 to BCD-022 or reference trastuzumab and were treated with trastuzumab + paclitaxel. Therapy continued for 6 cycles of therapy (every 3 weeks), until progression of the disease or unbearable toxicity. Primary study endpoint was overall response rate. Study goal was to prove equivalent efficacy of BCD-022 and reference trastuzumab. Equivalence margins for 95% CI for difference in overall response rates were set at [− 20%; 20%]. Results In total 225 patients were enrolled into the study, 115 in BCD-022 arm and 110 in reference trastuzumab arm. Overall response rate was 49.6% in BCD-022 arm and 43.6% in reference trastuzumab arm. Limits of 95% CI for difference of overall response rates between arms were [(− 8.05)-19.89%], thus, they lied within predetermined equivalence margins [− 20%; 20%]. Profile of adverse events was similar between groups (any AEs were reported in 93.81% of patients in BCD-022 arm and 94.55% of patients in reference arm). No unexpected adverse reactions were reported throughout the study. No statistically significant differences regarding antibody occurrence rate (either BAb or NAb) was found between BCD-022 ( n  = 3; 2.65%) and comparator ( n  = 4; 3.64%). Both drug products are characterized with low occurrence rate and short life of anti-trastuzumab antibodies. Pharmacokinetics assessment after 1st and 6th study drug injection also demonstrated equivalent PK parameters by all outcome measures: AUC 0–504 , С mах , Т max , T 1/2 . Analysis of C trough did not reveal any significant inter-group differences as well. Conclusions Thus, results of this study have demonstrated therapeutic equivalence of trastuzumab biosimilar BCD-022 and referent trastuzumab drug. Trial registration The trial was registered with ClinicalTrials.gov (Study Number NCT01764022 ). The date of registration was January 9, 2013.

Group-IV color centers in diamond are a promising light-matter interface for quantum networking devices. The negatively charged tin-vacancy center (SnV) is particularly interesting, as its large spin-orbit coupling offers strong protection against phonon dephasing and robust cyclicity of its optical transitions toward spin-photon-entanglement schemes. Here, we demonstrate multiaxis coherent control of the SnV spin qubit via an all-optical stimulated Raman drive between the ground and excited states. We use coherent population trapping and optically driven electronic spin resonance to confirm coherent access to the qubit at 1.7 K and obtain spin Rabi oscillations at a rate of Ω/2π=19.0(1) MHz. All-optical Ramsey interferometry reveals a spin dephasing time of T₂^(*)=1.3(3) μs, and four-pulse dynamical decoupling already extends the spin-coherence time to T₂=0.30(8) ms. Combined with transform-limited photons and integration into photonic nanostructures, our results make the SnV a competitive spin-photon building block for quantum networks.

Atomically thin layers of two-dimensional materials can be assembled in vertical stacks that are held together by relatively weak van der Waals forces, enabling coupling between monolayer crystals with incommensurate lattices and arbitrary mutual rotation 1 , 2 . Consequently, an overarching periodicity emerges in the local atomic registry of the constituent crystal structures, which is known as a moiré superlattice 3 . In graphene/hexagonal boron nitride structures 4 , the presence of a moiré superlattice can lead to the observation of electronic minibands 5 – 7 , whereas in twisted graphene bilayers its effects are enhanced by interlayer resonant conditions, resulting in a superconductor–insulator transition at magic twist angles 8 . Here, using semiconducting heterostructures assembled from incommensurate molybdenum diselenide (MoSe 2 ) and tungsten disulfide (WS 2 ) monolayers, we demonstrate that excitonic bands can hybridize, resulting in a resonant enhancement of moiré superlattice effects. MoSe 2 and WS 2 were chosen for the near-degeneracy of their conduction-band edges, in order to promote the hybridization of intra- and interlayer excitons. Hybridization manifests through a pronounced exciton energy shift as a periodic function of the interlayer rotation angle, which occurs as hybridized excitons are formed by holes that reside in MoSe 2 binding to a twist-dependent superposition of electron states in the adjacent monolayers. For heterostructures in which the monolayer pairs are nearly aligned, resonant mixing of the electron states leads to pronounced effects of the geometrical moiré pattern of the heterostructure on the dispersion and optical spectra of the hybridized excitons. Our findings underpin strategies for band-structure engineering in semiconductor devices based on van der Waals heterostructures 9 . Excitonic bands in MoSe 2 /WS 2 heterostructures can hybridize, resulting in a resonant enhancement of moiré superlattice effects.

An Amendment to this paper has been published and can be accessed via a link at the top of the paper.An Amendment to this paper has been published and can be accessed via a link at the top of the paper.

In 2016 we have upgraded the COMPASS RICH by novel gaseous photon detectors based on MPGD technology. Four new photon detectors, covering a total active area of 1.5 m 2 , have been installed in order to cope with the challenging efficiency and stability requirements of the COMPASS physics programme. The new detector architecture consists in a hybrid MPGD combination: two layers of THGEMs, the first of which also acts as a reflective photocathode thanks to CsI coating, are coupled to a bulk Micromegas on a pad-segmented anode. These detectors are the first application in an experiment of MPGD-based single photon detectors. Presently, we are further developing the MPGD-based PDs to make them adequate for a setup at the future EIC collider. All aspects of the COMPASS RICH-1 Photon Detectors upgrade are presented: R&D, engineering, mass production, QA and performance; the on-going development for collider application is also presented.

We outline a range of proposals on using quantum rings and nanohelices for terahertz device implementations. We show that an Aharonov-Bohm quantum ring system and a double-gated quantum ring system both permit control over the polarization properties of the associated terahertz radiation. In addition, we review the superlattice properties of a mathematically similar system, that of a nanohelix in external electric fields, which reveals negative differential conductance.