Directed and elliptic flows of neutrons and light-charged particles were measured for the reaction ${}^{197}\mathrm{Au}+{}^{197}\mathrm{Au}$ at 400 MeV/nucleon incident energy within the ASY-EOS experimental campaign at the GSI laboratory. The detection system consisted of the Large Area Neutron Detector (LAND), combined with parts of the CHIMERA multidetector, the ALADIN Time-of-flight Wall, and the Washington University Microball detector. The latter three arrays were used for the event characterization and reaction-plane reconstruction. In addition, an array of triple telescopes, KRATTA was used for complementary measurements of the isotopic composition and flows of light-charged particles. From the comparison of the elliptic-flow ratio of neutrons with respect to charged particles with UrQMD predictions, a value $\gamma =0.72\pm 0.19$ is obtained for the power-law coefficient describing the density dependence of the potential part in the parametrization of the symmetry energy. It represents a new and more stringent constraint for the regime of suprasaturation density and confirms, with a considerably smaller uncertainty, the moderately soft to linear density dependence deduced from the earlier FOPI-LAND data. The densities probed are shown to reach beyond twice saturation.

There have been substantial advances in the ability to monitor the activity of hazardous volcanoes in recent decades. However, obtaining early warning of eruptions remains challenging, because the patterns and consequences of volcanic unrests are both complex and nonlinear. Measuring volcanic gases has long been a key aspect of volcano monitoring since these mobile fluids should reach the surface long before the magma. There has been considerable progress in methods for remote andin-situgas sensing, but measuring the flux of volcanic CO₂—the most reliable gas precursor to an eruption—has remained a challenge. Here we report on the first direct quantitative measurements of the volcanic CO₂flux using a newly designed differential absorption lidar (DIAL), which were performed at the restless Campi Flegrei volcano. We show that DIAL makes it possible to remotely obtain volcanic CO₂flux time series with a high temporal resolution (tens of minutes) and accuracy (<30%). The ability of this lidar to remotely sense volcanic CO₂represents a major step forward in volcano monitoring and will contribute improved volcanic CO₂flux inventories. Our results also demonstrate the unusually strong degassing behavior of Campi Flegrei fumaroles in the current ongoing state of unrest.

We discuss results concerning the behavior of hot nuclear sources formed in 40,48Ca+40,48Ca reactions at 25~MeV/nucleon. A correlation between the neutron-to-proton ratio of the total systems and heavy residue production is found. This correlation underlines the strong role played by the neutron-to-proton ratio degree of freedom on the behavior of hot nuclei at intermediate energies. Comparisons of our data with Constrained Molecular Dynamics calculations confirm that a moderately stiff behavior of the symmetry potential must be used to reproduce experimental data. These findings open the way for future investigations with exotic beams at radioactive ion beam facilities.

The DFM/OPA-based lidar BILLI was used to investigate the volcanic plume released by the hydrothermal vent of Pisciarelli, in the Campi Flegrei volcano. BILLI remotely measured ${\mathrm{CO}}_2$ concentrations in cross-sections of the near-vent plume using the differential absorption technique. To our knowledge, this is the first example of lidar-based measurement of volcanic ${\mathrm{CO}}_2$. The spatial resolution was 1.5 m and the temporal resolution 20 s.

Quantum interference is a central resource in many quantum-enhanced tasks, from computation to communication. While usually occurring between identical photons, it can also be enabled by performing projective measurements that render the photons indistinguishable, a process known as quantum erasing. Structured light forms another hallmark of photonics, achieved by manipulating the degrees of freedom of light, and enables a multitude of applications in both classical and quantum regimes. By combining these ideas, we design and experimentally demonstrate a simple and robust scheme that tailors quantum interference to engineer photonic states with spatially structured coalescence along the transverse profile, a type of quantum mode with no classical counterpart. To achieve this, we locally tune the distinguishability of a photon pair by spatially structuring the polarization and creating a structured quantum eraser. We believe that these spatially engineered multiphoton quantum states may be of significance in fields such as quantum metrology, microscopy, and communication.