Influence of the coherence of spectral domain interference of Fano resonance on the degree of polarization of light

We show an intriguing connection between the coherence of spectral domain interference of two electromagnetic modes in Fano resonance and the resulting degree of polarization of light. A theoretical treatment is developed by combining a general electromagnetic model of partially coherent interference of a spectrally narrow and a broad continuum mode leading to Fano resonance and the cross-spectral density matrix of the interfering polarized fields of light. The model suggests a characteristic variation of the degree of polarization across the region of spectral dip and the peak of Fano resonance as an exclusive signature of the connection between the degree of polarization and the coherence of the interfering modes. The predictions of the model is experimentally verified in the partially polarized Fano resonance spectra from metal Chalcogenides systems, which emerged due to the interference of a narrow excitonic mode with the background continuum of scattered light in the reflectance spectra from the system. The demonstrated connection between polarization and coherence in the spectral domain Fano-type interference of electromagnetic modes is fundamentally important in the context of a broad variety of non-trivial wave phenomena that originate from fine interference effects, which may also have useful practical implications

Probing Spin Dynamics of 2D Excitons with Twisted Light

We propose a mechanism of intravalley spin–flip scattering in spin–valley-coupled two-dimensional (2D) systems by transferring the momentum of light into the exciton center of mass using optical vortex (OV) beams. By varying the dispersion of light using the topological charge of the OV beam, we demonstrate a unique approach to control the intravalley spin–flip scattering rate of excitons. From our photoluminescence measurements, we demonstrate that the intravalley scattering rate in W-based TMDs can be tuned externally by OV beams. Variation of photoluminescence intensity with topological charges shows a crossover temperature (>150 K), indicating competition among time scales involving radiative recombination, spin–flip scattering, and thermal relaxations. Our proposed technique utilizing a structured light beam can open up a new approach to exploring the physics of excitons in 2D systems

An updated mass-radius analysis of the 2017-2018 NICER data set of PSR J0030+0451

<p>Summarised posterior sample files associated with the preprint "An updated mass-radius analysis of the 2017-2018 NICER data set of PSR J0030+0451" by Vinciguerra et al. (2023; <a href="https://doi.org/10.48550/arXiv.2308.09469">arXiv</a>; accepted for publication in ApJ).</p><p>Also included are examples of model modules in the Python language using the X-PSI framework; and Jupyter analysis notebooks.</p><p>Please refer to the READme for detailed information.</p&gt

An updated mass-radius analysis of the 2017-2018 NICER data set of PSR J0030+0451

International audienceIn 2019 the NICER collaboration published the first mass and radius inferred for PSR J0030+0451, thanks to NICER observations, and consequent constraints on the equation of state characterising dense matter. Two independent analyses found a mass of $\sim 1.3-1.4\,\mathrm{M_\odot}$ and a radius of $\sim 13\,$km. They also both found that the hot spots were all located on the same hemisphere, opposite to the observer, and that at least one of them had a significantly elongated shape. Here we reanalyse, in greater detail, the same NICER data set, incorporating the effects of an updated NICER response matrix and using an upgraded analysis framework. We expand the adopted models and jointly analyse also XMM-Newton data, which enables us to better constrain the fraction of observed counts coming from PSR J0030+0451. Adopting the same models used in previous publications, we find consistent results, although with more stringent inference requirements. We also find a multi-modal structure in the posterior surface. This becomes crucial when XMM-Newton data is accounted for. Including the corresponding constraints disfavors the main solutions found previously, in favor of the new and more complex models. These have inferred masses and radii of $\sim [1.4 \mathrm{M_\odot}, 11.5$ km] and $\sim [1.7 \mathrm{M_\odot}, 14.5$ km], depending on the assumed model. They display configurations that do not require the two hot spots generating the observed X-rays to be on the same hemisphere, nor to show very elongated features, and point instead to the presence of temperature gradients and the need to account for them