In this paper we propose a two-field model of warm inflation motivated from a heterotic string construction. The model contains an axion and a dilaton-like field. We show that while warm inflation can take place in the axion-field direction, thermal corrections coming from the radiation gauge fields, which couples to both the axion and the dilaton, prevent warm inflation to happen in the dilaton-field direction. We explore the background dynamics for different parameters, and identify a diversity of dynamical behaviors allowed in this model, denoting different regimes of warm inflation.

We analyze the dynamics of the Bianchi I universe in modified loop quantum cosmology (Model I, or mLQC-I), uncovering a robust mechanism for isotropization. As in the standard LQC, the classical singularities are resolved by quantum bounce. Remarkably, mLQC-I exhibits a distinctive feature: following the bounce, the shear is dynamically suppressed and decays rapidly to zero within the deep quantum regime. This occurs independently of the collapsing matter fields, leading to a natural quantum isotropization. Consequently, the three spatial directions expand rapidly to macroscopic scales, producing a homogeneous and isotropic universe directly from the quantum epoch without fine-tuning. Our findings demonstrate that mLQC-I not only resolves singularities but also provides a more effective pathway for suppressing anisotropies than other models, thereby reinforcing its viability as a description of the early universe.

We clarify how the weak-interaction-driven bulk viscosity $\zeta$ and the bulk relaxation time $\tau_\Pi$ of neutrino-transparent $npe$ matter depend on the nuclear symmetry energy. We show that, at saturation density, the equation-of-state dependence of these transport quantities is fully determined by the experimentally constrained nuclear symmetry energy $S$ and its slope $L$. Variations of $L$ can change the bulk viscosity by orders of magnitude, which can affect both the dissipative and the conservative tidal response of neutron stars. This suggests that both conservative and dissipative effects encoded in the gravitational-wave signatures of binary neutron star inspirals may help constrain nuclear symmetry energy properties.

We propose a new method to investigate the existence and location of the conjectured high-temperature critical point of strongly interacting matter via contours of constant entropy density. By approximating these lines as a power series in the baryon chemical potential $\mu_B$, one can extrapolate them from first-principle results at zero net-baryon density, and use them to locate the QCD critical point, including the associated first-order and spinodal lines. As a proof of principle, we employ currently available continuum-extrapolated first-principle results from the Wuppertal--Budapest collaboration to find a critical point at a temperature and a baryon chemical potential of $T_c = 114.3 \pm 6.9$MeV and$\mu_{B,c} = 602.1 \pm 62.1$ MeV, respectively. We advocate for a more precise determination of the required expansion coefficients via lattice QCD simulations as a means of pinpointing the location of the critical endpoint in the phase diagram of strongly interacting matter.

The Southern Photometric Local Universe Survey (S-PLUS) is a project to map $\sim9300$ sq deg of the sky using twelve bands (seven narrow and five broadbands). Observations are performed with the T80-South telescope, a robotic telescope located at the Cerro Tololo Observatory in Chile. The survey footprint consists of several large contiguous areas, including fields at high and low galactic latitudes, and towards the Magellanic Clouds. S-PLUS uses fixed exposure times to reach point source depths of about $21$ mag in the $griz$ and $20$ mag in the $u$ and the narrow filters. This paper describes the S-PLUS Data Release 4 (DR4), which includes calibrated images and derived catalogues for over 3000 sq deg, covering the aforementioned area. The catalogues provide multi-band photometry performed with the tools \texttt{DoPHOT} and \texttt{SExtractor} -- point spread function (\PSF) and aperture photometry, respectively. In addition to the characterization, we also present the scientific potential of the data. We use statistical tools to present and compare the photometry obtained through different methods. Overall we find good agreement between the different methods, with a slight systematic offset of 0.05\,mag between our \PSF and aperture photometry. We show that the astrometry accuracy is equivalent to that obtained in previous S-PLUS data releases, even in very crowded fields where photometric extraction is challenging. The depths of main survey (MS) photometry for a minimum signal-to-noise ratio $S/N = 3$ reach from $\sim19.5$ for the bluer bands to $\sim21.5$ mag on the red. The range of magnitudes over which accurate \PSF photometry is obtained is shallower, reaching $\sim19$ to $\sim20.5$ mag depending on the filter. Based on these photometric data, we provide star-galaxy-quasar classification and photometric redshift for millions of objects.

Multi natural inflation is studied in the context of warm inflation. We study the warm multi natural inflation scenario with both linear and cubic dissipation coefficients. The model is motivated by axion-like inflation models with coupling to non-Abelian gauge fields through a dimension five coupling and dissipation originating from sphaleron decay in a thermal bath. Both cases of dissipation coefficients can be compatible with current observations. In the case of the cubic dissipation coefficient, we find that the curvature perturbation starts to grow suddenly when a transition from a weak dissipation to a strong dissipation regime occurs at the later stage of the inflation. We also show that such rapid growth of the curvature perturbation on small scales gives rise to abundant scalar induced gravitational waves, which may be detectable with future gravitational wave detectors such as DECIGO and ET. On the other hand, there are also other parameter regions of the model, in the warm inflation regime of weak to strong dissipation and with sub-Planckian axion decay constant, that can lead to overproduction of primordial black holes on small scales, which are constrained by nucleosynthesis bounds, thus ruling out the model in this region of parameters.

The microscopic quantum field theory origins of warm inflation dynamics are reviewed. The warm inflation scenario is first described along with its results, predictions and comparison with the standard cold inflation scenario. The basics of thermal field theory required in the study of warm inflation are discussed. Quantum field theory real time calculations at finite temperature are then presented and the derivation of dissipation and stochastic fluctuations are shown from a general perspective. Specific results are given of dissipation coefficients for a variety of quantum field theory interaction structures relevant to warm inflation, in a form that can readily be used by model builders. Different particle physics models realising warm inflation are presented along with their observational predictions.

The effective approach in Loop Quantum Cosmology (LQC) has provided means to obtain predictions for observable quantities in LQC models. While an effective dynamics in LQC has been extensively considered in different scenarios, a robust demonstration of the validity of effective descriptions for the perturbative level still requires further attention. The consistency of the description adopted in most approaches requires the assumption of a test field approximation, which is limited to the cases in which the backreaction of the particles gravitationally produced can be safely neglected. Within the framework of LQC, some of the main approaches to quantize the linear perturbations are the dressed metric, the hybrid approaches and the closed/deformed algebra approach. Here, we analyze the consistency of the test field assumption in these frameworks by computing the energy density stored in the particles gravitationally produced compared to the background energy density. This analysis ultimately provides us with a consistency test of the effective descriptions of LQC.

This work investigates a singularity-free early Universe within the paradigm of quantum cosmology. We develop a bouncing model where the singularity is resolved via the de Broglie-Bohm interpretation of quantum mechanics, which provides a deterministic trajectory for the scale factor through a quantum bounce. The primordial power spectrum for scalar perturbations is derived, incorporating a characteristic modulation (distortion function) imprinted by the non-standard quantum gravitational dynamics near the bounce. We confront this model with the Planck 2018 cosmic microwave background data, establishing its strong compatibility with observations. Our analysis places a stringent upper bound on the fundamental scale of the bounce, $k_B$, constraining the parameter space of such quantum cosmological scenarios. Furthermore, the model's specific scale-dependent anti-correlation between the spectral index and amplitude of perturbations offers a potential mechanism for mitigating the $H_0$-$\sigma_8$ tension, presenting a testable signature for future cosmological surveys.

We investigate an explicit example of how spatial decoherence can lead to hydrodynamic behavior in the late-time, long-wavelength regime of open quantum systems. We focus on the case of a single non-relativistic quantum particle linearly coupled to a thermal bath of noninteracting harmonic oscillators at temperature $T$, a la Caldeira and Leggett. Taking advantage of decoherence in the position representation, we expand the reduced density matrix in powers of the off-diagonal spatial components, so that high-order terms are suppressed at late times. Truncating the resulting power series at second order leads to a set of dissipative transient hydrodynamic equations similar to the non-relativistic limit of equations widely used in simulations of the quark-gluon plasma formed in ultrarelativistic heavy-ion collisions. Transport coefficients are directly determined by the damping constant $\gamma$, which quantifies the influence of the environment. The asymptotic limit of our hydrodynamic equations reduces to the celebrated Navier-Stokes equations for a compressible fluid in the presence of a drag force. Our results shed new light on the onset of hydrodynamic behavior in quantum systems with few degrees of freedom.

We determine the possible trajectories the universe may have followed in the QCD phase diagram during the QCD epoch. We focus on the roles of chiral symmetry breaking and pion condensation under high imbalances in lepton asymmetry. Adopting the quark-meson model as an effective description of QCD at finite temperature, charge and baryon chemical potentials we show that, for sufficiently large but physically motivated asymmetries, the universe may have entered the pion condensation phase through a first-order phase transition, followed by a second-order phase transition when exiting it. Such a first-order phase transition represents a new possible source of primordial gravitational waves during the QCD epoch.

We investigate the influence of spin polarization in strongly interacting matter by introducing a finite spin potential, $\mu_\Sigma$, which effectively controls the spin density of the system without requiring rotation or specific boundary conditions. Inspired by recent lattice QCD simulations that incorporated such a potential, we implement this approach within an effective QCD framework. Our results show that increasing spin polarization leads to a simultaneous decrease in both the chiral and deconfinement restoration temperatures. The resulting phase structure is qualitatively consistent with lattice findings, and notably, we observe the emergence of a first-order chiral phase transition at low temperature. These results suggest that spin-polarized environments can significantly impact the QCD phase diagram and offer a controlled route for studying spin effects in hot and dense matter.

An alternative approach to obtaining neutrino masses, distinct from the traditional seesaw mechanism, is proposed. This method relies on the simultaneous diagonalization of matrices derived from a twisted Lagrangian density of the neutrino matter sector. This approach avoids the need for introducing heavy Majorana neutrinos, thereby reducing the number of free parameters in the Standard Model (SM). We present numerical results for neutrino masses that align with experimental data, and we introduce a new parameter, $\alpha_\nu$, to fine-tune the mass differences $\Delta m^2_{21}$ and $\Delta m^2_{31}$. The proposed framework connects the neutrino mass generation mechanism to the known masses of quarks and charged leptons, providing an unified perspective on the matter sector of the Standard Model.

We consider several families of functions $f(\alpha)$ that appear in the Bona-Masso slicing condition for the lapse function $\alpha$. Focusing on spherically symmetric and time-independent slices we apply these conditions to the Schwarzschild spacetime in order to construct analytical expressions for the lapse $\alpha$ in terms of the areal radius $R$. We then transform to isotropic coordinates and determine the dependence of $\alpha$ on the isotropic radius $r$ in the vicinity of the black-hole puncture. We propose generalizations of previously considered functions $f(\alpha)$ for which, to leading order, the lapse is proportional to $r$ rather than a non-integer power of $r$. We also perform dynamical simulations in spherical symmetry and demonstrate advantages of the above choices in numerical simulations employing spectral methods.

A dissipative mechanism is presented, which emerges in generic interacting quantum field systems and which leads to robust warm inflation. An explicit example is considered, where using typical parameter values, it is shown that considerable radiation can be produced during inflation. The extension of our results to expanding spacetime also is discussed.

The recently released data from the $\textit{Atacama Cosmology Telescope}$ (ACT) confirms that the primordial scalar spectrum is extremely flat. This, together with current upper bounds on the tensor-to-scalar ratio, implies that the simplest models of inflation coming from particle physics (for instance, a minimally-coupled scalar with monomial potentials) need additional ingredients in order to make them compatible with observations. Instead of invoking arbitrary new couplings or new interactions that are not protected symmetries, we argue that dissipation of the inflaton field with the radiation bath should be added as a new physical principle. Accordingly, we show that warm inflation provides the correct paradigm to explain the current observations, given very natural choices of dissipative terms.

In this paper an agent-based simulation is developed in order to evaluate an AmI scenario based on agents. Many AmI applications are implemented through agents but they are not compared to any other existing alternative in order to evaluate the relative benefits of using them. The proposal simulation environment developed in Netlogo analyse such benefits using two evaluation criteria: First, measuring agent satisfaction of different types of desires along the execution. Second, measuring time savings obtained through a correct use of context information. So, here, a previously suggested agent architecture, an ontology and a 12-steps protocol to provide AmI services in airports, is evaluated using a NetLogo simulation environment. The present work uses a NetLogo model considering scalability problems of this application domain but using FIPA and BDI extensions to be coherent with our previous works and our previous JADE implementation of them. The NetLogo model presented simulates an airport with agent users passing through several zones located in a specific order in a map: passport controls, check-in counters of airline companies, boarding gates, different types of shopping. Although initial data in simulations are generated randomly, and the model is just an approximation of real-world airports, the definition of this case of use of Ambient Intelligence through NetLogo agents opens an interesting way to evaluate the benefits of using Ambient Intelligence, which is a significant contribution to the final development of them.