Search results for "theoretical physics"
showing 10 items of 751 documents
Multi-field, multi-frequency bosonic stars and a stabilization mechanism
2021
Scalar bosonic stars (BSs) stand out as a multi-purpose model of exotic compact objects. We enlarge the landscape of such (asymptotically flat, stationary, everywhere regular) objects by considering multiple fields (possibly) with different frequencies. This allows for new morphologies ${\it and}$ a stabilization mechanism for different sorts of unstable BSs. First, any odd number of complex fields, yields a continuous family of BSs departing from the spherical, equal frequency, $\ell-$BSs. As the simplest illustration, we construct the $\ell$ = ${\it 1}$ ${\it BSs}$ ${\it family}$, that includes several single frequency solutions, including even parity (such as spinning BSs and a toroidal,…
Unified description of structure and reactions: implementing the Nuclear Field Theory program
2015
The modern theory of the atomic nucleus results from the merging of the liquid drop (Niels Bohr and Fritz Kalckar) and of the shell model (Marie Goeppert Meyer and Axel Jensen), which contributed the concepts of collective excitations and of independent-particle motion respectively. The unification of these apparently contradictory views in terms of the particle-vibration (rotation) coupling (Aage Bohr and Ben Mottelson) has allowed for an ever increasingly complete, accurate and detailed description of the nuclear structure, Nuclear Field Theory (NFT, developed by the Copenhagen-Buenos Aires collaboration) providing a powerful quantal embodiment. In keeping with the fact that reactions are…
The structure of cosmic voids in a LCDM Universe
2013
Eulerian cosmological codes are especially suited to properly describe the low density regions. This property makes this class of codes excellent tools to study the formation and evolution of cosmic voids. Following such ideas, we present the results of an Eulerian adaptive mesh refinement (AMR) hydrodynamical and N-body simulation, that contrary to the common practice, has been designed to refine the computational grid in the underdense regions of the simulated volume. Thus, the void regions are better described due to the combined effect of the Eulerian character of the numerical technique and the use of high numerical resolution from the AMR approach. To analyse the outcome of this simul…
Exploring Interacting Topological Insulators with Ultracold Atoms: The Synthetic Creutz-Hubbard Model
2016
25 pags., 13 figs. -- Open Access funded by Creative Commons Atribution Licence 4.0
Role of information backflow in the emergence of quantum Darwinism
2019
Quantum Darwinism attempts to explain the emergence of objective reality of the state of a quantum system in terms of redundant information about the system acquired by independent non interacting fragments of the environment. The consideration of interacting environmental elements gives rise to a rich phenomenology, including the occurrence of non-Markovian features, whose effects on objectification {\it a' la} quantum Darwinism needs to be fully understood. We study a model of local interaction between a simple quantum system and a multi-mode environment that allows for a clear investigation of the interplay between information trapping and propagation in the environment and the emergence…
Open questions about homogeneous fluid dynamos: The VKS experiment
2002
International audience; We consider several problems that arise in the context of homogeneous fluid dynamos such as the effect of turbulence on the dynamo threshold, the saturation level of the generated magnetic field above the threshold and its dynamics. We compare some of our predictions with the recent experimental results of the Karlsruhe and Riga experiments. Finally, we present the VKS experiment that we have designed to answer some of the remaining open questions. We study, in particular, the response of a turbulent flow to an external magnetic field.
Elucidating the electron transport in semiconductors via Monte Carlo simulations: An inquiry-driven learning path for engineering undergraduates
2015
Within the context of higher education for science or engineering undergraduates, we present an inquiry-driven learning path aimed at developing a more meaningful conceptual understanding of the electron dynamics in semiconductors in the presence of applied electric fields. The electron transport in a nondegenerate n-type indium phosphide bulk semiconductor is modelled using a multivalley Monte Carlo approach. The main characteristics of the electron dynamics are explored under different values of the driving electric field, lattice temperature and impurity density. Simulation results are presented by following a question-driven path of exploration, starting from the validation of the model…
Enseñanza de las ciencias : revista de investigación y experiencias didácticas
2021
Resumen. La conservación de la energía es uno de los conceptos más importantes de la física porque unifi ca todos los fenómenos. En este artículo presentamos algunos resultados de una investigación sobre el proceso de enseñanza-aprendizaje del concepto de energía y su conservación realizado en el nivel de la educación secundaria española. El análisis de los datos pone de manifiesto que la conservación de la energía se introduce en mecánica y termodinámica pero no en todos los campos de la física. Los resultados experimentales se han utilizado para desarrollar un nuevo enfoque de la enseñanza de la energía. Palabras clave. Energía, educación en física, actividades de enseñanza. Summary. The …
The virial theorem and the dark matter problem in hybrid metric-Palatini gravity
2012
Hybrid metric-Palatini gravity is a recently proposed theory, consisting of the superposition of the metric Einstein-Hilbert Lagrangian with an f(R) term constructed a la Palatini. The theory predicts the existence of a long-range scalar field, which passes the Solar System observational constraints, even if the scalar field is very light, and modifies the cosmological and galactic dynamics. Thus, the theory opens new possibilities to approach, in the same theoretical framework, the problems of both dark energy and dark matter. In this work, we consider the generalized virial theorem in the scalar-tensor representation of the hybrid metric-Palatini gravity. More specifically, taking into ac…
A duality-invariant Einstein-Planck relation and its consequences on micro-black holes.
2013
We discuss the consequences of a duality-invariant Einstein–Planck (DIEP) relation on the equation of state of micro black holes. The results are analogous to those obtained from the "world-crystal" model, but with some significative differences, as for instance a limiting vanishing value for temperature for very small black holes. The model leads to a total evaporation of micro black holes but with the final stage being very slow.