Pump-probe spectroscopy is a nonlinear technique utilized to investigate the dynamics of ultrafast electrons [1]. This method involves focusing a short pulse of a strong pump beam and, after a certain delay time, a weak probe beam on a sample to record its transmittance, influenced by the pump. In the majority of experiments targeting nonlinear optical phenomena, such as the pump-probe...
Hexagonal boron nitride (h-BN) is a promising two-dimensional material due to its properties, such as high thermal conductivity and excellent thermochemical stability (1). h-BN can host numerous optically structural defects (2,3). The production of h-BN films on Cu foil using an ammonia borane (NH3BH3) precursor is investigated. The growth is performed via atmospheric-pressure chemical vapor...
Hf/ZrO2 -based ferroelectric (FE) thin films provide increasingly promising technical solutions for extensive application in low-power and high-speed memory due to its CMOS-compatibility and high scalability. Ferroelectricity in Hf/ZrO2 thin films arises from the polar orthorhombic Pca21 phase (o-phase), while in bulk the stable phases are the monoclinic P21/c phase (m-phase) around room...
Topological insulators have attracted researchers’ attention recently due to their unique surface states protected by time-reversal symmetry [1-5]. Since Bi2Se3 has a low bandgap, it is expected to perform well in photodetection for visible and infrared optoelectronics [6, 7]. Here, we present the preliminary results from our work on the growth, cleanroom fabrication, and characterization of...
Despite the shortcomings of the Standard Model, all experimental observations so far have not indicated the existence of new physics (NP) at or near the TeV scale. The gravitational channel is another promising avenue to test NP and can potentially probe particles with masses far beyond those accessible at current collider experiments. With this in mind, we perform a phenomenological study of...
We explore the implications of low reheating temperatures in the early Universe, focusing on scenarios where a minimal threshold of $4$ MeV is crucial to preserve the accuracy of Big Bang Nucleosynthesis (BBN) predictions. We specifically investigate the freeze-in mechanism, wherein Dark Matter (DM) candidates are Boltzmann suppressed due to their mass exceeding the reheating temperature....
We analyze two-dimensional scattering matrices for particles transforming in the fundamental representation of the U(N) global symmetry group, assuming no bound states. In particular, we use the S-matrix bootstrap formalism to construct the allowed space of S-matrices for such processes, which in turn need to be consistent with the usual conditions of unitarity, crossing and analyticity....
Conformal field theories (CFTs) are a subset of quantum field theories which are invariant under conformal transformations. CFTs are of great theoretical interest, partly due to the AdS/CFT conjecture, which asserts that a gravitational theory living in $d$-dimensional Anti-de Sitter (AdS) space is dual to a CFT on the $(d-1)$-dimensional boundary of this space. This is a powerful...
The presently open problem of the Hubble tension is shown to be removed in the context of a modified theory of gravity with a non-minimal coupling between curvature and matter. By evolving the cosmological parameters that match the cosmic microwave background data until their values from direct late-time measurements, we will show how to obtain an agreement between different experimental...
What does a black hole look like? In 1 + 3 spacetime dimensions, the optical appearance of a black hole is a bidimensional region in the observer’s sky often called the black hole shadow, as supported by the EHT observations. In higher dimensions this question is more subtle and observational setup dependent. Previous studies considered the shadows of higher dimensional black holes to remain...
Sulfonamides are a class of synthetic broad spectrum antimicrobial drugs widely used in animal farms and human medicine. Sulfamethoxazole (SMX) is the most prevalent sulfonamide and has been detected in different aquatic environments in concentrations as high as 49.7 µg L-1 [1]. The scientific community and health organizations are increasingly concerned due to the potential toxicity to...
The Pierre Auger Observatory, the world’s largest experiment in the study of the highest energy astroparticles, is being upgraded with new detector technologies to reduce its current systematic uncertainties and accurately determine the mass composition of Ultra High Energy Cosmic Rays (UHECRs). The Underground Muon Detector (UMD), a part of the recent low-energy extension of the observatory,...
We perform Monte-Carlo measurements of two and three-point functions of
charged operators in the critical O(2) model in 3 dimensions. Our results are compatible
with the predictions of the large charge superfluid effective field theory. We improved the Worm algorithm to obtain reliable
measurements for large charge values. We devised
a measurement scheme that mitigates the uncertainties...
Tailoring the excitation of higher order modes (HOM) is of great importance across several applications within the photonics field, including optofluidics sensing, nonlinear phenomena generation, imaging, and in fiber communication systems. Nevertheless, effectively exciting specific HOM still remains a challenge.
Currently, HOM can be achieved resorting to certain optical devices such as...
A proof-of-concept test bench to assess the quality and operation of rangefinders and LiDARs in a compact setup with a footprint small enough to sit on a usual optical table. In particular, the development subsystem includes an apparatus capable of measuring the maximum range of the rangefinder type of instrument. The range measurement will be implemented by mimicking a real backscattering...
The Standard Model (SM) can be considered an effective low-energy expression of a more fundamental theory.
Several observed phenomena cannot be explained by the SM, the existence of dark matter (DM) being one of them.
At the Large Hadron Collider (LHC), protons can stay intact after the interaction and be scattered by very small angles, which are then detected by the ATLAS Forward Proton...
This presentation summarizes the advances made in the first two years of my PhD fellowship program. Significant progress has been achieved in the area of laser-writing of nitrogen-vacancy (NV) centers, characterization of fluorescence microscopy and developing of ODMR systems and protocols for optimized sensitivity.
Advancements were made in the laser writing of NV center ensembles in...
In High Energy Physics, when testing theoretical models of new physics against
experimental results, the customary approach is to simply sample random points from
the parameter space of the model, calculate their predicted values for the desired
observables and compare them to experimental data. However, due to the typically
large number of parameters in these models, this process is...
We study the dynamical stability of Proca-Higgs stars, in spherical symmetry. These are solutions of the Einstein-Proca-Higgs model, which features a Higgs-like field coupled to a Proca field, both of which minimally coupled to the gravitational field. The corresponding stars can be regarded as Proca stars with self-interactions, while avoiding the hyperbolicity issues of self-interacting...
This study evaluates the performance of the Weather Research and Forecasting (WRF) model in simulating temperature, wind speed, and precipitation across six Weather Types (WTs) in Portugal. We compare six Planetary Boundary Layer (PBL) parameterizations, using observational data from IPMA for validation. Key metrics—Root Mean Square Error (RMSE), Bias, and Standard Deviation of Errors...
Spherical Proca Stars (PSs) are regarded as the ground state amongst the family of PSs. In accordance, spherical PSs are thought to have a fundamental branch of stable solutions.We provide energetic, morphological and dynamical evidence that spherical PSs are actually excited states. The ground state is shown to be a family of static, non-spherical, in fact prolate, PSs. The spherical stars in...
Extreme fire events have been increasingly frequent under changing Climate. Improving landscape resilience is key in reducing the ecological and socio-economic impacts of wildfires. This work aims to provide groundwork to incorporate future climate compatible land management scenarios with fire spread modelling tools. In this scope, the coupled fire-atmosphere modelling system WRF-SFIRE was...
We study the 2→2 scattering in the regime where the wavelength of the scattered objects is comparable to their distance but is much larger than any Compton wavelength in the quantum field theory. We observe that in this regime - which differs from the eikonal - the Feynman diagram expansion takes the form of a geometric series, akin to the Born series of quantum mechanics. Conversely, we can...
Atmospheric aerosols are known to significantly influence global and regional climates through their interactions with radiation and cloud microphysical processes. However, these interactions are difficult to represent in the current atmospheric chemistry models, because of their dependence on aerosol chemical composition, concentration, and size, which are intrinsically linked to aerosol...
Gravitational wave approximants are extremely useful tools in gravitational wave astronomy. By skipping the full evolution of numerical relativity waveforms, their usage allows for dense coverage of the parameter space of binary black hole (BBH) mergers for purposes of parameter inference, or, more generally, match filtering tasks. However, these benefits come at a slight cost to accuracy when...
The baryon asymmetry problem remains a crucial challenge in particle physics and cosmology. Electroweak baryogenesis, a leading mechanisms to produce the matter-antimatter asymmetry we observe today, requires an extension to the Standard Model to achieve a sufficiently strong first order phase transition.
Besides representing a target for several future-generation colliders, such Beyond the...
