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We review the so-called Nikiforov-Uvarov method along with some basic results about classical orthogonal polynomials and hypergeometric functions related to the hypergeometric differential equation. The method is employed to address certain eigenvalue problems that appear in quantum mechanics, namely, time-independent Schr\"odinger equation, paying special attention to properly and completely characterising its spectrum. Finally, some potentials are discussed and solved.

By means of a diffusion Monte Carlo technique, we study one-dimensional mixtures of fermionic Ytterbium atoms ($^{173}$Yb, $^{171}$Yb) in which the total number of $^{173}$Yb particles is different from the sum of all the atoms belonging to the $^{171}$Yb isotope. Even tough self-bound droplets are possible for different compositions, the most stable ones are clusters with a slight excess of attractively interacting $^{171}$Yb particles belonging to different spins with respect to the number of spin-polarized $^{173}$Yb atoms., Comment: arXiv admin note: text overlap with arXiv:2312.17654

Using a diffusion Monte Carlo algorithm, we calculated the spectra of all possible $S$-wave fully heavy pentaquarks within the framework of the quark model. Our aim was to compare the masses of different spin-color configurations corresponding to the same spatial wavefunction for each quark composition. In particular, we computed the masses of the configuration with the maximum number of undistinguishable quarks and those of all the possible baryon+meson splittings compatible with the total number of $b$'s and $c$'s for a given pentaquark. What we found was that, in all cases, compact baryon+meson configurations had lower masses than their more symmetric counterparts. Moreover, those "molecular" associations were unstable (with larger masses) that their infinitely separated non-interacting pieces except int the case of $(ccb)(c\bar{b})$ and $(bbc)(b\bar{c})$ pentaquarks. In any case, even for unstable arrangements, the excess masses are so small ($\sim$20-60 MeV) as to make those compact molecular structures serious candidates to be experimentally detected.

Learning about databases is indispensable for individuals studying software engineering or computer science or those involved in the IT industry. We analyzed a remote educational escape room for teaching about databases in four different higher education courses in two consecutive academic years. We employed three instruments for evaluation: a pre- and post-test to assess the escape room's effectiveness for student learning, a questionnaire to gather students' perceptions, and a Web platform that unobtrusively records students' interactions and performance. We show novel evidence that educational escape rooms conducted remotely can be engaging as well as effective for teaching about databases.

Using a diffusion Monte Carlo (DMC) technique, we calculated the phase diagram of 3He adsorbed on a first solid layer of a molecular hydrogen isotope (H2,HD and D2) on top of graphite. The results are qualitatively similar in all cases: a two-dimensional gas spanning from the infinite dilution limit to a second-layer helium density of 0.048 +/- 0.004 Ang^{-2}. That gas is in equilibrium with a 7/12 commensurate structure, more stable than any incommensurate triangular solid of similar density. These findings are in reasonably good agreement with available experimental data., Comment: To appear in J. Chem. Phys

Contribution: This article analyzes the learning effectiveness of a virtual educational escape room for teaching software engineering and compares this activity with traditional teaching through a randomized controlled trial. Background: Educational escape rooms have been used across a wide variety of disciplines at all levels of education and they are becoming increasingly popular among teachers. Nevertheless, there is a clear general need for more robust empirical evidence on the learning effectiveness of these novel activities and, particularly, on their application in software engineering education. Research Questions: Is game-based learning using educational escape rooms more effective than traditional lectures for teaching software engineering? What are the perceptions of software engineering students toward game-based learning using educational escape rooms? Methodology: The study presented in this article is a randomized controlled trial with a pre-and post-test design that was completed by a total of 326 software engineering students. The 164 students belonging to the experimental group learned software modeling by playing an educational escape room whereas the 162 students belonging to the control group learned the same subject matter through a traditional lecture. Findings: The results of the randomized controlled trial show that the students who learned software modeling through the educational escape room had very positive perceptions toward this activity, significantly increased their knowledge, and outperformed those students who learned through a traditional lecture in terms of knowledge acquisition., Comment: 9 pages, 1 figure. Journal article published in IEEE Transactions on Education

Contribution: This article analyzes the learning and motivational impact of teacher-authored educational video games on computer science education and compares its effectiveness in both face-to-face and online (remote) formats. This work presents comparative data and findings obtained from 217 students who played the game in a face-to-face format (control group) and 104 students who played the game in an online format (experimental group). Background: Serious video games have been proven effective at computer science education, however, it is still unknown whether the effectiveness of these games is the same regardless of their format, face-to-face or online. Moreover, the usage of games created through authoring tools has barely been explored. Research Questions: Are teacher-authored educational video games effective in terms of learning and motivation for computer science students? Does the effectiveness of teacher-authored educational video games depend on whether they are used in a face-to-face or online format? Methodology: A quasi-experiment has been conducted by using three instruments (pre-test, post-test, and questionnaire) with the purpose of comparing the effectiveness of game-based learning in face-to-face and online formats. A total of 321 computer science students played a teacher-authored educational video game aimed to learn about software design. Findings: The results reveal that teacher-authored educational video games are highly effective in terms of knowledge acquisition and motivation both in face-to-face and online formats. The results also show that some students' perceptions were more positive when a face-to-face format was used., Comment: 10 pages, 3 figures. Accepted version of a journal article published in IEEE Transactions on Education

Significant research work has been undertaken related to the game-based learning approach over the last years. However, a closer look at this work reveals that further research is needed to examine some types of game-based learning approaches such as virtual reality serious games and LEGO Serious Play. This article examines and compares the effectiveness for learning Scrum and related agile practices of a serious game based on virtual reality and a learning activity based on the LEGO Serious Play methodology. The presented study used a quasi-experimental design with two groups, pre- and post-tests, and a perceptions questionnaire. The sample was composed of 59 software engineering students, 22 of which belonged to group A, while the other 37 were part of group B. The students in group A played the virtual reality serious game, whereas the students in group B conducted the LEGO Serious Play activity. The results show that both game-based learning approaches were effective for learning Scrum and related agile practices in terms of learning performance and motivation, but they also show that the students who played the virtual reality serious game outperformed their peers from the other group in terms of learning performance., Comment: 15 pages, 4 figures. Journal article published in Applied Sciences

The wave-like behaviour of matter in quantum physics has spurred insightful analogies between the dynamics of particles and waves in classical systems. In this study, drawing inspiration from synchrotrons that resonate to accelerate ions along a closed path, we introduce the concept of a synchrowave: a waveguide designed to generate and sustain travelling water waves within a closed annular channel. In analogy to unavoidable energy losses in conventional particle accelerators due to electromagnetic radiation and inelastic collisions, the system displays undesired water-wave dampening, which we address through the synchronised action of underwater wavemakers. Our analogies extend the resonance mechanisms of synchrotrons to generate gravity waves in closed waveguides efficiently. A proof-of-concept experiment at a laboratory scale demonstrates the unique capability of this technique to build up anomalously large travelling waves displaying a flat response in the long-wave limit. Besides quantifying the performance of wave generation, our findings offer a framework for both industrial and computational applications, opening up unexplored possibilities in hydraulics, coastal science and engineering. In a broader context, our experimental apparatus and methods highlight the versatility of a simple yet powerful concept: a closed-path continuous-energy-pumping scheme to effectively harvest prominent resonant responses within wave-supporting systems displaying weak dissipation., Comment: 7 figures

Multiquark systems appear less frequently than mesons and baryons despite the enormous world-wide experimental effort that has been made during the last two decades. In this work, we will propose a possible explanation for that fact, restricting ourselves to the case of sets including only $c$ and $\bar{c}$ quarks. We will show that those multiquarks can be thought as different combinations of smaller units that associate together to produce colorless assemblies with a definite value of the total spin. For instance, for the $cccccc$ hexaquark with $S=0$, we have three possibilities: a set of six undistinguishable $c$ quarks, an association of two $ccc$ baryons, or a set of three $cc$ diquarks close together. This means we can have three different values for the mass of an open-charm hexaquark with $S=0$. Using the diffusion Monte Carlo method, we calculate all possible combinations compatible with tetraquark $cc \bar{c} \bar{c}$, pentaquark $cccc \bar{c}$, open-charm $cccccc$ and hidden-charm $ccc \bar{c} \bar{c} \bar{c}$ hexaquark structures with the minimum value of total spin ($S=0$ or $S=1/2$). We consider compact structures with radial wave functions including interactions between all the quarks in the cluster. We find that, in all cases, the mass of the multiquark decreases with the number of small units that conform the set of quarks. For instance, an open charm hexaquark made up of three diquarks has a smaller mass than a set of six of $c$ undistinguishable units. When the pieces that conform the multiquark are themselves colorless with a definite value of the total spin, the cluster splits into those smaller units that separate infinitely from each other., Comment: 6 pages, 2 tables

Dry-wall laser inertial fusion (LIF) chambers will have to withstand strong bursts of fast charged particles which will deposit tens of kJ m$^{-2}$ and implant more than 10$^{18}$ particles m$^{-2}$ in a few microseconds at a repetition rate of some Hz. Large chamber dimensions and resistant plasma-facing materials must be combined to guarantee the chamber performance as long as possible under the expected threats: heating, fatigue, cracking, formation of defects, retention of light species, swelling and erosion. Current and novel radiation resistant materials for the first wall need to be validated under realistic conditions. However, at present there is a lack of facilities which can reproduce such ion environments. This contribution proposes the use of ultra-intense lasers and high-intense pulsed ion beams (HIPIB) to recreate the plasma conditions in LIF reactors. By target normal sheath acceleration, ultra-intense lasers can generate very short and energetic ion pulses with a spectral distribution similar to that of the inertial fusion ion bursts, suitable to validate fusion materials and to investigate the barely known propagation of those bursts through background plasmas/gases present in the reactor chamber. HIPIB technologies, initially developed for inertial fusion driver systems, provide huge intensity pulses which meet the irradiation conditions expected in the first wall of LIF chambers and thus can be used for the validation of materials too.

Our main result states that whenever we have a non-Euclidean norm $\|\cdot\|$ on a two-dimensional vector space $X$, there exists some $x\neq 0$ such that for every $\lambda\neq 1, \lambda>0$, there exist $y, z\in X$ verifying that $\|y\|=\lambda\|x\|$, $z\neq 0$, and $z$ belongs to the bisectors $B(-x,x)$ and $B(-y,y)$. Throughout this paper we also state and prove some other simple but maybe useful results about the geometry of the unit sphere of strictly convex planes.

The curvature tensor of a symplectic connection, as well as its covariant derivatives, satisfy certain identities that hold on any manifold of dimension less than or equal to a fixed n. In this paper, we prove certain results regarding these curvature identities. Our main result describes, for any fixed dimension and any even number p of indices, the first space (provided we have filtered the identities by a homogeneity condition) of p-covariant curvature identities. To this end, we use recent results on the theory of natural operations on Fedosov manifolds. These results allow us to apply the invariant theory of the symplectic group, with a method that is analogous to that used in Riemannian or Kahler geometry., Comment: Accepted for publication in Journal of Geometry and Physics

Current methods to identify and classify racist language in text rely on small-n qualitative approaches or large-n approaches focusing exclusively on overt forms of racist discourse. This article provides a step-by-step generalizable guideline to identify and classify different forms of racist discourse in large corpora. In our approach, we start by conceptualizing racism and its different manifestations. We then contextualize these racist manifestations to the time and place of interest, which allows researchers to identify their discursive form. Finally, we apply XLM-RoBERTa (XLM-R), a cross-lingual model for supervised text classification with a cutting-edge contextual understanding of text. We show that XLM-R and XLM-R-Racismo, our pretrained model, outperform other state-of-the-art approaches in classifying racism in large corpora. We illustrate our approach using a corpus of tweets relating to the Ecuadorian ind\'igena community between 2018 and 2021., Comment: 37 pages, 5 figures, 4 tables

We reveal for the first time by experiments that within a narrow parameter regime, two cavitation bubbles with identical energy generated in anti-phase develop a supersonic jet. High-resolution numerical simulation shows a mechanism for jet amplification based on toroidal shock wave and bubble necking interaction. The micro-jet reaches velocities in excess of 1000 m/s. We demonstrate that potential flow approximation established for Worthington jets accurately predicts the evolution of the bubble gas-liquid interfaces., Comment: 17 pages, 8 figures

The structure of self-bound one-dimensional droplets containing a mixture of Ytterbium fermionic isotopes ($^{173}$Yb, $^{171}$Yb) is calculated by means of a diffusion Monte Carlo technique. We considered only balanced setups in which all the atoms of one isotope are spin-polarized, while the atoms of the other can have up to three different spin values, that difference being a necessary requirement to achieve stable systems. Our results indicate that these droplets consist of consecutive "molecules" made up of one $^{173}$Yb and one $^{171}$Yb atom. In other words, we have up to three different kinds of composite bosons, corresponding to the number of spin components in the non-polarized isotope. The fermionic nature of those Yb atoms makes pairs with identical spin composition avoid each other, creating a Pauli-like-hole filed by another molecule in which at least one of the Yb atoms has a different spin from that of their closest neighbors. This effective repulsion is akin to an antiferromagnetic short-range interaction between different kinds of composite bosons., Comment: 5 pages, 4 figures

The influence of attractive boron impurities, embedded on a graphene sheet, on the phase diagrams of $^4$He and H$_2$ adsorbed on top was studied using the diffusion Monte Carlo method. The doping of graphene was made by distributing the boron atoms following the same pattern found in an experimentally synthesized substrate. Our results show that while the different incommensurate solid phases of both adsorbates remain largely unchanged after doping, the liquid/gas equations of state are significanty different from the ones on pristine graphene. Doping graphene produces new translationally invariant stable phases for $^4$He, depending on the concentration of boron impurities, but makes the H$_2$ ground state to remain solid. In addition, several new registered phases appear for both adsorbates., Comment: 8 pages

Dark matter and cosmic inflation represent two of the major puzzles in cosmology. They are typically addressed by introducing separate fields with independent dynamics. On the other hand, extra dimensions might play an important role for observable physics. We introduce a five-dimensional model called dark inflaxion that includes an axion-like particle, whose Kaluza-Klein modes can describe inflation and dark matter. We show that a simple yet natural choice of the mass scale of the effective four-dimensional fields of our model can accommodate simultaneously the observable values of inflationary parameters and dark-matter abundance. It will be interesting to explore the consequences and predictions of more generic scenarios within the scope of our model, which include the possibility of multifield inflation and dark matter., Comment: 29 pages + references, 13 figures, 2 tables

The properties of fully-heavy arrangements including a number of quarks between 5 and 12 were calculated within the framework of a constituent quark model by using a diffusion Monte Carlo technique. We considered only clusters in which all the quarks had the same mass, and whose number of particles and antiparticles were adequate to produce color singlets. All the multiquarks were in their lowest possible values of $L^2$ and $S^2$ operators. This means that we considered only color-spin wavefunctions that were antisymmetric with respect to the interchange of {\em any} two quarks of the same type. We found that in both all-$c$ and all-$b$ multiquarks, the mass per particle levels off for arrangements with a number of quarks larger of equal than six. The analysis of their structure implies that the fully-heavy multiquarks are compact structures., Comment: 5 pages, 4 figures

Rejuvenation and memory, long considered the distinguishing features of spin glasses, have recently been proven to result from the growth of multiple length scales. This insight, enabled by simulations on the Janus~II supercomputer, has opened the door to a quantitative analysis. We combine numerical simulations with comparable experiments to introduce two coefficients that quantify memory. A third coefficient has been recently presented by Freedberg et al. We show that these coefficients are physically equivalent by studying their temperature and waiting-time dependence., Comment: 10 pages, 8 figures

We unveil the multifractal behavior of Ising spin glasses in their low-temperature phase. Using the Janus II custom-built supercomputer, the spin-glass correlation function is studied locally. Dramatic fluctuations are found when pairs of sites at the same distance are compared. The scaling of these fluctuations, as the spin-glass coherence length grows with time, is characterized through the computation of the singularity spectrum and its corresponding Legendre transform. A comparatively small number of site pairs controls the average correlation that governs the response to a magnetic field. We explain how this scenario of dramatic fluctuations (at length scales smaller than the coherence length) can be reconciled with the smooth, self-averaging behavior that has long been considered to describe spin-glass dynamics., Comment: 15 pages, 15 figures