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We describe some dynamical properties of one parameter families of billiards on convex curves (ovals) which are deformed by the curvature (curve-shortening) flow. We obtain the bifurcations of the period two orbits and some special non-Birkhoff orbits, the normal periodic orbits. We prove the destruction of non-convex caustics of the ellipse by deforming it through the curvature flow.

In this study we perform numerical calculations of the spatial and time variation of the magnetic induction, current density and temperature in an infinite superconducting slab with macroscopic inhomogeneities. We also modeled an homogeneuos superconductor as a referential material, considering characteristic magnetothermal properties of a high-T$_c$ single crystal. The theoretical formalism is enclosed in the dynamical regime and a continuum electrodynamic approach. In particular, we studied the correlation between the magnetic jumps and temperature rise occurrence with the presence of macroscopical inhomogeneities, modeled through an stochastic current-carrying ability spatial profile.

Homemade spectrometers are commonly used tools to analyze light sources and determine its physical characteristics. We perform an assessment of homemade spectrometers in terms of spectral resolution and accuracy in the determination of intensity, through the comparison of results with a spectroscope commonly used in the physics and chemistry labs. We found that the homemade spectrometer used is sufficiently accurate in wavelength, and can be used by undergraduate students to perform precise measurements as, for example, the spectrum of the Sun, leading to the determination of its temperature., Comment: 15 pages, 6 figures

We find constraints on the highest scale of symmetry breaking of a model with gauge symmetry $SU(3)_C \otimes SU(3)_L \otimes U(1)_X$ with heavy neutral leptons in the fermion triplets, calculating the anomalous magnetic moment of the muon and using results of the relic abundance of dark matter and experiments searching for its direct detection. In order to do this, we have calculated the one-loop contribution of new particles in the model to $(g-2)_{\mu}$, finding a favoured region for the scale at which $SU(3)_L$ is broken, and we have found lower bounds for this scale making a comparison of the predictions for the detection of a fermion dark matter candidate in the model in terms of simplified dark matter models, identifying the dominant portal for its interactions with standard model particles, and using constraints for the relic abundance and spin-independent scattering cross section of the fermion candidate with protons., Comment: 25 pages, 1 Table, 6 figures

This is the third out of five chapters of the final report [1] of the Workshop on Physics at HL-LHC, and perspectives on HE-LHC [2]. It is devoted to the study of the potential, in the search for Beyond the Standard Model (BSM) physics, of the High Luminosity (HL) phase of the LHC, defined as $3~\mathrm{ab}^{-1}$ of data taken at a centre-of-mass energy of $14~\mathrm{TeV}$, and of a possible future upgrade, the High Energy (HE) LHC, defined as $15~\mathrm{ab}^{-1}$ of data at a centre-of-mass energy of $27~\mathrm{TeV}$. We consider a large variety of new physics models, both in a simplified model fashion and in a more model-dependent one. A long list of contributions from the theory and experimental (ATLAS, CMS, LHCb) communities have been collected and merged together to give a complete, wide, and consistent view of future prospects for BSM physics at the considered colliders. On top of the usual standard candles, such as supersymmetric simplified models and resonances, considered for the evaluation of future collider potentials, this report contains results on dark matter and dark sectors, long lived particles, leptoquarks, sterile neutrinos, axion-like particles, heavy scalars, vector-like quarks, and more. Particular attention is placed, especially in the study of the HL-LHC prospects, to the detector upgrades, the assessment of the future systematic uncertainties, and new experimental techniques. The general conclusion is that the HL-LHC, on top of allowing to extend the present LHC mass and coupling reach by $20-50\%$ on most new physics scenarios, will also be able to constrain, and potentially discover, new physics that is presently unconstrained. Moreover, compared to the HL-LHC, the reach in most observables will generally more than double at the HE-LHC, which may represent a good candidate future facility for a final test of TeV-scale new physics., Comment: Report from Working Group 3 on the Physics of the HL-LHC, and Perspectives at the HE-LHC; v2: final version updated with the latest contributions and summaries; 239 pages + refs; v3: typos and character misprint in Fig. 7.2 fixed; v4: added one missing author

By applying copositivity criterion to the scalar potential of the economical $3-3-1$ model, we derive necessary and sufficient bounded-from-below conditions at tree level. Although these are a large number of intricate inequalities for the dimensionless parameters of the scalar potential, we present general enlightening relations in this work. Additionally, we use constraints coming from the minimization of the scalar potential by means of the orbit space method, the positivity of the squared masses of the extra scalars, the Higgs boson mass, the $Z'$ gauge boson mass and its mixing angle with the SM $Z$ boson in order to further restrict the parameter space of this model., Comment: 22 pages, 7 figures, added text and references. Matches published version

The goal of this research is the study of the thermomagnetic consequences in isotropic type-II superconductors, subjected to multi-component magnetic fields $\mathbf{H}_a = H_{ay}\hat{y}+H_{az}\hat{z}$, because the instability field $\mathbf{H}_{fi}$ is closely related with a flux jump occurrence. At the critical-state model framework, once the Lorentz $\mathbf{F}_L$ and pinning forces $\mathbf{F}_P$ are at equilibrium, the current density reaches a critical value $j_c$ and a stationary magnetic induction distribution $\mathbf{B}$ is established. The equilibrium of forces is analytically solved considering that the pinning force is mainly affected by temperature increments; the energy dissipation is incorporated throughout the heat equation at the adiabatic regime. The theory is able to obtain the instability field according to the thermal bath and applied field values; moreover, it provides of instability field branches comprising both partial and full penetrates states. With this information is possible to construct a field-temperature map. The results are compared with already published experimental data, finding a qualitatively agreement between them. This theoretical study works with a first order perturbation, then the perturbation presents a periodical behavior along the thickness direction; considering this environment it is constructed the magnetic induction distributions which resemble flexible cantilever structures., Comment: 11 pages,2 figures, 1 table

We present the construction and performance of an ultra-low temperature scanning tunneling microscope (STM), working in ultra-high vacuum conditions (UHV) and in high magnetic fields up to 9 T. The cryogenic environment of the STM is generated by a single shot $^3$He magnet cryostat in combination with a $^4$He dewar system. At base temperature (300~mK), the cryostat has an operation time of approximately 80 hours. The special design of the microscope allows the transfer of the STM head from the cryostat to a UHV-chamber system, where samples and STM-tips can be easily exchanged. The UHV chambers are equipped with specific surface science treatment tools for the functionalization of samples and tips, including high-temperature treatments and thin film deposition. This, particularly, enables spin-resolved tunneling measurements. We present test measurements using well known samples and tips based on superconductor and metallic materials such as LiFeAs, Nb, Fe and W, respectively. The measurements demonstrate the outstanding performance of the STM with high spatial and energy resolution as well as the spin-resolved capability., Comment: 12 pages, 16 figures

GRB 160625B, one of the brightest bursts in recent years, was simultaneously observed by Fermi and Swift satellites, and ground-based optical telescopes in three different events separated by long periods of time. In this paper the non-thermal multiwavelength observations of GRB 160625B are described and a transition phase from wind-type-like medium to interstellar medium between the early (event II) and the late (event III) afterglow is found. The multiwavelength observations of the early afterglow are consistent with the afterglow evolution starting at $\sim$ 150 s in a stellar wind medium whereas the observations of the late afterglow are consistent with the afterglow evolution in interstellar medium (ISM). The wind-to-ISM transition is calculated to be at $\sim 8\times 10^3$ s when the jet has decelerated, at a distance of $\sim$ 1 pc from the progenitor. Using the standard external shock model, the synchrotron and synchrotron self-Compton emission from reverse shock is required to model the GeV $\gamma$-ray and optical observations in the early afterglow, and synchrotron radiation from the adiabatic forward shock to describe the X-ray and optical observations in the late afterglow. The derived values of the magnetization parameter, the slope of the fast decay of the optical flash and the inferred magnetic fields suggest that Poynting flux-dominated jet models with arbitrary magnetization could account for the spectral properties exhibited by GRB 160625B., Comment: 9 pages, 2 figure and 3 tables. References were added. Accepted for publication in ApJ

We study the resistive switching (RS) mechanism as way to obtain multi-level memory cell (MLC) devices. In a MLC more than one bit of information can be stored in each cell. Here we identify one of the main conceptual difficulties that prevented the implementation of RS-based MLCs. We present a method to overcome these difficulties and to implement a 6-bit MLC device with a manganite-based RS device. This is done by precisely setting the remnant resistance of the RS-device to an arbitrary value. Our MLC system demonstrates that transition metal oxide non-volatile memories may compete with the currently available MLCs., Comment: Accepted for publication in the IEEE Transactions on CAS II