Author Correction: Carbon nanotubes as emerging quantum-light sources.

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

Seismic Stereometry Reveals Preparatory Behavior and Source Kinematics of Intermediate-Size Earthquakes.

Although moderate-size earthquakes are poorly studied by lack of near-fault observations, they can provide key information about larger damaging earthquakes. Here we propose a new approach, inspired by double-difference relocation, that uses high-coherency waveforms recorded at neighboring sensors, to study the preparation phase and dynamics of moderate-size earthquakes. We validate this technique by analyzing the 2016, M w 5.2 Borrego Springs earthquake in Southern California and find consistent rupture velocities of 2 km/s highlighting two main rupture asperities. The analysis of the 2019, Ml5.2 Le Teil earthquake in France reveals slow nucleation at depth that migrates to the surface and propagates northward with a velocity of ∼2.8 km/s, highlighting two main rupture events also imaged by InSAR. By providing unprecedented resolution in our observation of the rupture dynamics, this approach will be useful in better understanding the preparation phase and rupture of both tectonic and induced earthquakes.

Superlocalization of Excitons in Carbon Nanotubes at Cryogenic Temperature.

At cryogenic temperature and at the single emitter level, the optical properties of single-wall carbon nanotubes depart drastically from that of a one-dimensional (1D) object. In fact, the (usually unintentional) localization of excitons in local potential wells leads to nearly 0D behaviors such as photon antibunching, spectral diffusion, inhomogeneous broadening, etc. Here, we present a hyperspectral imaging of this spontaneous exciton localization effect at the single nanotube level using a super-resolved optical microscopy approach. We report on the statistical distribution of the trap localization, depth, and width. We use a quasi-resonant photoluminescence excitation approach to probe the confined quantum states. Numerical simulations of the quantum states and exciton diffusion show that the excitonic states are deeply modified by the interface disorder inducing a remarkable discretization of the excitonic absorption spectrum and a quenching of the free 1D exciton absorption.

Publisher Correction: Carbon nanotubes as emerging quantum-light sources.

In the version of this Perspective originally published, the x-axis label of Fig. 1d was missing; it should have read 'Wavelength (nm)'. The units of the y axis of Fig. 3b were incorrect; they should have been meV. And the citation of Fig. 3c in the main text was incorrect; it should have been to Fig. 3b. These issues have now been corrected.

Carbon nanotubes as emerging quantum-light sources.

Progress in quantum computing and quantum cryptography requires efficient, electrically triggered, single-photon sources at room temperature in the telecom wavelengths. It has been long known that semiconducting single-wall carbon nanotubes (SWCNTs) display strong excitonic binding and emit light over a broad range of wavelengths, but their use has been hampered by a low quantum yield and a high sensitivity to spectral diffusion and blinking. In this Perspective, we discuss recent advances in the mastering of SWCNT optical properties by chemistry, electrical contacting and resonator coupling towards advancing their use as quantum light sources. We describe the latest results in terms of single-photon purity, generation efficiency and indistinguishability. Finally, we consider the main fundamental challenges stemming from the unique properties of SWCNTs and the most promising roads for SWCNT-based chip integrated quantum photonic sources.

Exploiting One-Dimensional Exciton-Phonon Coupling for Tunable and Efficient Single-Photon Generation with a Carbon Nanotube.

Condensed-matter emitters offer enriched cavity quantum electrodynamical effects due to the coupling to external degrees of freedom. In the case of carbon nanotubes, a very peculiar coupling between localized excitons and the one-dimensional acoustic phonon modes can be achieved, which gives rise to pronounced phonon wings in the luminescence spectrum. By coupling an individual nanotube to a tunable optical microcavity, we show that this peculiar exciton-phonon coupling is a valuable resource to enlarge the tuning range of the single-photon source while keeping an excellent exciton-photon coupling efficiency and spectral purity. Using the unique flexibility of our scanning fiber cavity, we are able to measure the efficiency spectrum of the very same nanotube in the Purcell regime for several mode volumes. Whereas this efficiency spectrum looks very much like the free-space luminescence spectrum when the Purcell factor is small (large mode volume), we show that the deformation of this spectrum at lower mode volumes can be traced back to the strength of the exciton-photon coupling. It shows an enhanced efficiency on the red wing that arises from the asymmetry of the incoherent energy exchange processes between the exciton and the cavity. This allows us to obtain a tuning range up to several hundred times the spectral width of the source.

Phonon-Photon Mapping in a Color Center in Hexagonal Boron Nitride.

We report on the ultraviolet optical response of a color center in hexagonal boron nitride. We demonstrate a mapping between the vibronic spectrum of the color center and the phonon dispersion in hexagonal boron nitride, with a striking suppression of the phonon assisted emission signal at the energy of the phonon gap. By means of nonperturbative calculations of the electron-phonon interaction in a strongly anisotropic phonon dispersion, we reach a quantitative interpretation of the acoustic phonon sidebands from cryogenic temperatures up to room temperature. Our analysis provides an original method for estimating the spatial extension of the electronic wave function in a point defect.

Widely Tunable Single-Photon Source from a Carbon Nanotube in the Purcell Regime.

The narrow emission of a single carbon nanotube at low temperature is coupled to the optical mode of a fiber microcavity using the built-in spatial and spectral matching brought by this flexible geometry. A thorough cw and time-resolved investigation of the very same emitter both in free space and in cavity shows an efficient funneling of the emission into the cavity mode together with a strong emission enhancement corresponding to a Purcell factor of up to 5. At the same time, the emitted photons retain a strong sub-Poissonian statistics. By exploiting the cavity feeding effect on the phonon wings, we locked the emission of the nanotube at the cavity resonance frequency, which allowed us to tune the frequency over a 4 THz band while keeping an almost perfect antibunching. By choosing the nanotube diameter appropriately, this study paves the way to the development of carbon-based tunable single-photon sources in the telecom bands.

Unifying the low-temperature photoluminescence spectra of carbon nanotubes: the role of acoustic phonon confinement.

At low temperature the photoluminescence of single-wall carbon nanotubes show a large variety of spectral profiles ranging from ultranarrow lines in suspended nanotubes to broad and asymmetrical line shapes that puzzle the current interpretation in terms of exciton-phonon coupling. Here, we present a complete set of photoluminescence profiles in matrix embedded nanotubes including unprecedented narrow emission lines. We demonstrate that the diversity of the low-temperature luminescence profiles in nanotubes originates in tiny modifications of their low-energy acoustic phonon modes. When low-energy modes are locally suppressed, a sharp photoluminescence line as narrow as 0.7 meV is restored. Furthermore, multipeak luminescence profiles with specific temperature dependence show the presence of confined phonon modes.

Optically gated resonant emission of single quantum dots.

We report on the resonant emission in coherently driven single semiconductor quantum dots. We demonstrate that an ultraweak nonresonant laser acts as an optical gate for the quantum dot resonant response. We show that the gate laser suppresses Coulomb blockade at the origin of a resonant emission quenching, and that the optically gated quantum dots systematically behave as ideal two-level systems in both regimes of coherent and incoherent resonant emission.

Detection of a biexciton in semiconducting carbon nanotubes using nonlinear optical spectroscopy.

We report the observation of the biexciton in semiconducting single-wall carbon nanotubes by means of nonlinear optical spectroscopy. Our measurements reveal the universal asymmetric line shape of the Fano resonance intrinsic to the biexciton transition. For nanotubes of the (9,7) chirality, we find a biexciton binding energy of 106 meV. From the calculation of the χ((3)) nonlinear response, we provide a quantitative interpretation of our measurements, leading to an estimation of the characteristic Fano factor q of 7 ± 3. This value allows us to extract the first experimental information on the biexciton stability and we obtain a biexciton annihilation rate comparable to the exciton-exciton annihilation one.

Hot electron cooling by acoustic phonons in graphene.

We have investigated the energy loss of hot electrons in metallic graphene by means of GHz noise thermometry at liquid helium temperature. We observe the electronic temperature T ∝ V at low bias in agreement with the heat diffusion to the leads described by the Wiedemann-Franz law. We report on T ∝ √V behavior at high bias, which corresponds to a T(4) dependence of the cooling power. This is the signature of a 2D acoustic phonon cooling mechanism. From a heat equation analysis of the two regimes we extract accurate values of the electron-acoustic phonon coupling constant Σ in monolayer graphene. Our measurements point to an important effect of lattice disorder in the reduction of Σ, not yet considered by theory. Moreover, our study provides a strong and firm support to the rising field of graphene bolometric detectors.

Hyper-Kähler Manifolds of Generalized Kummer Type and the Kuga-Satake Correspondence.

We first describe the construction of the Kuga-Satake variety associated to a (polarized) weight-two Hodge structure of hyper-Kähler type. We describe the classical cases where the Kuga-Satake correspondence between a hyper-Kähler manifold and its Kuga-Satake variety has been proved to be algebraic. We then turn to recent work of O'Grady and Markman which we combine to prove that the Kuga-Satake correspondence is algebraic for projective hyper-Kähler manifolds of generalized Kummer deformation type.

Elastic exciton-exciton scattering in photoexcited carbon nanotubes.

We report on original nonlinear spectral hole-burning experiments in single wall carbon nanotubes that bring evidence of pure dephasing induced by exciton-exciton scattering. We show that the collision-induced broadening in carbon nanotubes is controlled by exciton-exciton scattering as for Wannier excitons in inorganic semiconductors, while the population relaxation is driven by exciton-exciton annihilation as for Frenkel excitons in organic materials. We demonstrate that this singular behavior originates from the intrinsic one-dimensionality of excitons in carbon nanotubes, which display unique hybrid features of organic and inorganic systems.

Case reports of medication-related osteonecrosis of the jaw (MRONJ) treated with uncultured stromal vascular fraction and L-PRF.

Medication-related osteonecrosis of the jaw (MRONJ) is a challenging affection, considering the absence of a "Gold Standard" treatment. Cell therapy and tissue engineering, using adipose-tissue stromal vascular fraction (SVF) containing mesenchymal stromal cells (MSC) and endothelial progenitor cells (EPC); and a scaffold with healing properties, l-platelet-rich fibrin (L-PRF), could be a therapeutic option. Two cases of MRONJ were treated by tissue engineering. The patients presented respectively a stage-II and a stage-III MRONJ. The protocol consists of SVF injection in the L-PRF applied on the cleaned bone. Patients are followed clinically and by medical imaging (MI) for 18 months. The buccal mucosa was closed within a month. No recurrence was observed during the follow-up. The MI highlighted bone formation. MSC and EPC presence, in the SVF, were confirmed by immunophenotyping. We report the preliminary results of MRONJ patients successfully treated with the association of autologous fresh L-PRF-SVF.

Infant swimming in chlorinated pools and the risks of bronchiolitis, asthma and allergy.

Recent studies suggest that swimming in chlorinated pools during infancy may increase the risks of lower respiratory tract infection. The aim of the present study was to assess the influence of swimming in chlorinated pools on the risks of bronchiolitis and its late consequences. A total of 430 children (47% female; mean age 5.7 yrs) in 30 kindergartens were examined. Parents completed a questionnaire regarding the child's health history, swimming practice and potential confounders. Attendance at indoor or outdoor chlorinated pools ever before the age of 2 yrs was associated with an increased risk of bronchiolitis (OR 1.68; 95% CI 1.08-2.68; p = 0.03), which was exposure-dependent for both types of pool (p-value for trend <0.01). Associations persisted, and were even strengthened, by the exclusion of other risk factors. Among children with no parental antecedents of atopic disease or no day-care attendance, odds ratios for bronchiolitis amounted to 4.45 (1.82-10.9; p = 0.001) and 4.44 (1.88-10.5; p = 0.007) after >20 h spent in chlorinated pools during infancy. Infant swimmers who developed bronchiolitis also showed higher risks of asthma and respiratory allergies later in childhood. Swimming pool attendance during infancy is associated with a higher risk of bronchiolitis, with ensuing increased risks of asthma and allergic sensitisation.

Mandibular feminization osteotomy-preliminary results.

Strong mandibular angles and a heavy chin are perceived as masculine features, so surgical feminization of female or transgender faces may warrant mandibular base narrowing (borders and angles) and a reduction in chin width and height. With this in mind, we have devised an interdental midline osteotomy (triangular in shape and with a caudal base) to accompany a box-shaped impaction osteotomy of the chin symphysis and horizontal triangular resection of the lateral mandibular border. The reduction of the intergonial width and of the mandibular border and chin widths takes place upon closure of the midline defect. Between November 2016 and August 2017, five patients agreed to the mandibular feminization osteotomy and were followed up thereafter for 6-13 months. All expressed satisfaction with the results; no dental, periodontal, or temporomandibular joint-related complications were encountered. This technique is a viable alternative to buccal decortication, chin reduction osteotomy, and masseter reduction surgery.

Outdoor swimming pools and the risks of asthma and allergies during adolescence.

Exposure to indoor chlorinated swimming pools can be detrimental to the airways of swimmers and increase asthma risks but it is unknown whether these effects concern outdoor pools. The present study examined 847 secondary school adolescents who had attended residential or nonresidential outdoor chlorinated pools at a variable rate. The main outcomes were: ever asthma (physician-diagnosed at any time); current asthma (ever asthma under medication and/or with exercise-induced bronchoconstriction); elevated exhaled nitric oxide; and aeroallergen-specific immunoglobulin (Ig)E in serum. The prevalence of ever and current asthma significantly increased with the lifetime number of hours spent in outdoor pools by up to four and eight times, respectively, among adolescents with the highest attendance (>500 h) and a low exposure to indoor pools (<250 h). Odds for asthma were significantly increased among adolescents with total serum IgE >25 kIU x L(-1), on average by 1-2 units for each 100-h increase in pool attendance. Use of residential outdoor pools was also associated with higher risks of elevated exhaled nitric oxide and sensitisation to cat or house dust mite allergens. Outdoor chlorinated swimming pool attendance is associated with higher risks of asthma, airways inflammation and some respiratory allergies.

Interplay of spectral diffusion and phonon-broadening in individual photo-emitters: the case of carbon nanotubes.

At cryogenic temperatures, the photoluminescence (PL) spectrum of nano-emitters may still be significantly broadened due to interactions with the environment. The interplay of spectral diffusion (SD) and phonon broadening in this context is still a debated issue. Singlewall carbon nanotubes (SWNTs) are a particularly relevant system to address this topic as they show intense spectral diffusion and undergo a high exciton-phonon coupling due to their one-dimensional geometry. Here, we investigate the correlations between the spectral diffusion of the main line and that of the wings in SWNTs quantitatively and demonstrate that the photoluminescence spectrum undergoes spectral jumps as a whole, without distortions. This behavior suggests that the spectral shape of SWNT PL is defined by exciton-phonon interactions and that spectral diffusion results in an additional flat broadening. The methodology developed here can be used to investigate a broad range of non-Lorentzian emitters undergoing spectral diffusion.

Diameter-selective non-covalent functionalization of carbon nanotubes with porphyrin monomers.

We report on the spontaneous non-covalent functionalization of carbon nanotubes with hydrophobic porphyrin molecules in micellar aqueous solution. By monitoring the species concentrations with optical spectroscopies, we can follow the kinetics of the reaction and study its thermodynamical equilibrium as a function of the reagent concentrations. We show that the reaction is well accounted for by a cooperative Hill equation, reaching a molecular coverage close to a compact monolayer for a porphyrin concentration larger than a diameter-specific threshold concentration. The equilibrium constant is measured for 16 nanotube chiral species. The Gibbs energy of the reaction (of the order of -40 kJ mol(-1)) and its evolution with the nanotube diameter is consistent with theoretical calculations of the binding energy. This thermodynamical study shows a strong preferential binding of TPP molecules to larger diameter nanotubes. This original curvature selectivity can be used to induce diameter selective species enrichment.