Pion and kaon condensation in a 3-flavor NJL model

We analyze the phase diagram of a three-flavor Nambu-Jona-Lasinio model at finite temperature $T$ and chemical potentials $\mu_u, \mu_d, \mu_s$. We study the competition of pion and kaon condensation and we propose a physical situation in which kaon condensation could be led only by light quark finite densities.Comment: 21 pages, 8 figures include

A NJL-based study of the QCD critical line

We employ a 3 flavor NJL model to stress some general remarks about the QCD critical line. The dependence of the critical curve on $\mu_q=(\mu_u+\mu_d)/2$ and $\mu_I=(\mu_u-\mu_d)/2$ is discussed. The quark masses are varied to confirm that, in agreement with universality arguments, the order of transition depends on the number of active flavors $N_f$. The slope of the critical curve vs. chemical potential is studied as a function of $N_f$. We compare our results with those recently obtained in lattice simulations to establish a comparison among different models.Comment: 17 pages, 5 figure

Structural and spectral characterisation of Er3+ and Nd3+ doped Ga-La-S-Se glasses

In this work, the spectroscopy of Er3+ and Nd3+ doped Se-GLS glasses was studied. A structural comparison between doped and non-doped samples was done to assess the differences between the glasses. For this comparison, Raman spectroscopy and thermal analysis were employed. The spectral properties of the samples were studied in order to identify the mechanisms responsible for quenching the fluorescence lifetime of the dopants. In particular, cross-relaxation and concentration quenching were observed in Nd3+ doped samples, whilst co-operative upconversion, radiation trapping and concentration quenching were observed in Er3+ doped samples. The results obtained demonstrated the fundamental role of the phonon energy in the mechanism of fluorescence. The low phonon energy of chalcogenides decreased the rate of non-radiative processes promoting co-operative upconversion. This effect could be exploited to design new lasers and sensitizers for solar energy harvesters

Resonance Recombination Model and Quark Distribution Functions in the Quark-Gluon Plasma

We investigate the consequences of space-momentum correlations in quark phase-space distributions for coalescence processes at the hadronization transition. Thus far it has been proved difficult to reconcile such correlations with the empirically observed constituent quark number scaling (CQNS) at the Relativistic Heavy-Ion Collider (RHIC). To address this problem we combine our earlier developed quark recombination model with quark phase-space distributions computed from relativistic Langevin simulations in an expanding Quark-Gluon Plasma (QGP). Hadronization is based on resonance formation within a Boltzmann equation which recovers thermal equilibrium and obeys energy conservation in the quark-coalescence process, while the fireball background is adjusted to hydrodynamic simulations of semi-central Au-Au collisions at RHIC. To facilitate the applicability of the Langevin process, we focus on strange and charm quarks. Their interactions in the QGP are modeled using leading-order perturbative QCD augmented by effective Lagrangians with resonances which smoothly merge into hadronic states formed at T_c. The interaction strength is adjusted to reproduce the empirical saturation value for the quark-elliptic flow, v_{2,q}^{sat}~7-8%. The resulting phi and J/\psi elliptic flow recover CQNS over a large range in transverse momentum (p_T) within a few percent. As a function of transverse kinetic energy, both the quark spectra from the Langevin simulations and the meson spectra generated via resonance recombination recover CQNS from zero to at least 3 GeV.Comment: 10 pages, 6 figures; v2: modified title, light-quark results taken out, version accepted for publication in PR

Real Time Full-Color Imaging in a Meta-Optical Fiber Endoscope

Endoscopes are an important component for the development of minimally invasive surgeries. Their size is one of the most critical aspects, because smaller and less rigid endoscopes enable higher agility, facilitate larger accessibility, and induce less stress on the surrounding tissue. In all existing endoscopes, the size of the optics poses a major limitation in miniaturization of the imaging system. Not only is making small optics difficult, but their performance also degrades with downscaling. Meta-optics have recently emerged as a promising candidate to drastically miniaturize optics while achieving similar functionalities with significantly reduced size. Herein, we report an inverse-designed meta-optic, which combined with a coherent fiber bundle enables a 33% reduction in the rigid tip length over traditional gradient-index (GRIN) lenses. We use the meta-optic fiber endoscope (MOFIE) to demonstrate real-time video capture in full visible color, the spatial resolution of which is primarily limited by the fiber itself. Our work shows the potential of meta-optics for integration and miniaturization of biomedical devices towards minimally invasive surgery

Ladder-QCD at finite isospin chemical potential

We use an effective QCD model (ladder-QCD) to explore the phase diagram for chiral symmetry breaking and restoration at finite temperature with different $u,d$ quark chemical potentials. In agreement with a recent investigation based on the Nambu-Jona-Lasinio model, we find that a finite pion condensate shows up for high enough isospin chemical potential $\mu_{I}=(\mu_{u}-\mu_{d})/2$. For small $\mu_{I}$ the phase diagram in the $(\mu_B,T)$ plane shows two first order transition lines and two critical ending points.Comment: Typed in RevTex4, pages 12, figures 2. Two references adde

A calculation of the QCD phase diagram at finite temperature, and baryon and isospin chemical potentials

We study the phases of a two-flavor Nambu-Jona-Lasinio model at finite temperature $T$, baryon and isospin chemical potentials: $\mu_{B}=(\mu_{u}+\mu_{d})/2$, $\mu_{I}=(\mu_{u}-\mu_{d})/2$. This study completes a previous analysis where only small isospin chemical potentials $\mu_{I}$ were consideredComment: 21 pages, 13 figures included, two more refernces adde

Occupational risk of nano-biomaterials: Assessment of nano-enabled magnetite contrast agent using the BIORIMA Decision Support System

The assessment of the safety of nano-biomedical products for patients is an essential prerequisite for their market authorization. However, it is also required to ensure the safety of the workers who may be unintentionally exposed to the nano-biomaterials (NBMs) in these medical applications during their synthesis, formulation into products and end-of-life processing and also of the medical professionals (e.g., nurses, doctors, dentists) using the products for treating patients. There is only a handful of workplace risk assessments focussing on NBMs used in medical applications. Our goal is to contribute to increasing the knowledge in this area by assessing the occupational risks of magnetite (Fe3O4) nanoparticles coated with PLGA-b-PEG-COOH used as contrast agent in magnetic resonance imaging (MRI) by applying the software-based Decision Support System (DSS) which was developed in the EU H2020 project BIORIMA. The occupational risk assessment was performed according to regulatory requirements and using state-of-the-art models for hazard and exposure assessment, which are part of the DSS. Exposure scenarios for each life cycle stage were developed using data from literature, inputs from partnering industries and results of a questionnaire distributed to healthcare professionals, i.e., physicians, nurses, technicians working with contrast agents for MRI. Exposure concentrations were obtained either from predictive exposure models or monitoring campaigns designed specifically for this study. Derived No-Effect Levels (DNELs) were calculated by means of the APROBA tool starting from in vivo hazard data from literature. The exposure estimates/measurements and the DNELs were used to perform probabilistic risk characterisation for the formulated exposure scenarios, including uncertainty analysis. The obtained results revealed negligible risks for workers along the life cycle of magnetite NBMs used as contrast agent for the diagnosis of tumour cells in all exposure scenarios except in one when risk is considered acceptable after the adoption of specific risk management measures. The study also demonstrated the added value of using the BIORIMA DSS for quantification and communication of occupational risks of nano-biomedical applications and the associated uncertainties

Degenerate distributions in complex Langevin dynamics: one-dimensional QCD at finite chemical potential

We demonstrate analytically that complex Langevin dynamics can solve the sign problem in one-dimensional QCD in the thermodynamic limit. In particular, it is shown that the contributions from the complex and highly oscillating spectral density of the Dirac operator to the chiral condensate are taken into account correctly. We find an infinite number of classical fixed points of the Langevin flow in the thermodynamic limit. The correct solution originates from a continuum of degenerate distributions in the complexified space.Comment: 20 pages, several eps figures, minor comments added, to appear in JHE

The QCD confinement transition: hadron formation

We review the foundations and the applications of the statistical and the quark recombination model as hadronization models.Comment: 45 pages, 16 figures, accepted for publication in Landolt-Boernstein Volume 1-23