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In this work, we use valley-topological triangular resonators coupled to an input waveguide to evaluate the quality of the topological protection. To that purpose, we first analyze via numerical simulations the existence of backward scattering at cavity corners or transmission with pseudo-spin conversion at the splitter between the input waveguide and the cavity. We evidence that a breakdown of topological protection takes place, in particular at sharp corners, which results in transmission minima and split-resonances, otherwise non-existent. In order to evaluate the small coupling coefficients associated to this breakdown, a phenomenological model based on an exact parameterization of scattering matrices at splitters and corners of the resonators is then introduced. By comparison with the numerical simulations, we are able to quantify the loss of topological protection at sharp bends and splitters. Finally, we use the obtained set of phenomenological parameters to compare the predictions of the phenomenological model with full numerical simulations for fractal-inspired cavities based on the Sierpi\'nski triangle construction. We show that the agreement is overall good, but shows more differences for the cavity composed of the smallest triangles. Our results suggest that even in a system exempt of geometrical and structural defects, topological protection is not complete at corners, sharp bends and splitters. However, simpler but predictive calculations can be realized with a phenomenological approach, allowing simulations of very large devices beyond the reach of standard simulation methods, which is crucial to design photonic devices which gather compactness and low losses through topological conduction of electromagnetic waves., Comment: 24 pages, 7 figures, one supplementary informations file

El presente trabajo versa sobre la concurrencia de varios delitos cometidos por una misma persona. El principal problema que se plantea es la delimitación entre aquellos supuestos en los que se comete una única infracción y, por tanto, habrá que aplicar un solo precepto de los concurrentes, y aquellos supuestos en que se cometen varios delitos, en cuyo caso estaremos ante un auténtico concurso de delitos. Además, será preciso distinguir cuándo un sujeto ha cometido una pluralidad de delitos a través de una única acción o a través de varias acciones, pues de ello va a depender que estemos ante un concurso ideal o real, lo cual tiene importantes consecuencias desde el punto de vista del régimen punitivo de ambos tipos de concurso., This work deals with the concurrence of several crimes committed by a same person. The main problem considered is the delimitation between those cases in which an only offense is committed and, therefore, a single precept will have to be applied, and those cases in which several crimes are committed, in which case we will face an authentic concurrence. Furthermore, it will be necessary to distinguish when a subject has committed multiple crimes by means of an only action or through various actions, since this will determine if we are facing an ideal or a real concurrence, which has important consequences from the punitive regime’s point of view of both types of concurrence, Departamento de Derecho Penal e Historia y Teoría del Derecho, Grado en Derecho

Revealing universal behaviors is a hallmark of statistical physics. Phenomena such as the stochastic growth of crystalline surfaces, of interfaces in bacterial colonies, and spin transport in quantum magnets all belong to the same universality class, despite the great plurality of physical mechanisms they involve at the microscopic level. This universality stems from a common underlying effective dynamics governed by the non-linear stochastic Kardar-Parisi-Zhang (KPZ) equation. Recent theoretical works suggest that this dynamics also emerges in the phase of out-of-equilibrium systems displaying macroscopic spontaneous coherence. Here, we experimentally demonstrate that the evolution of the phase in a driven-dissipative one-dimensional polariton condensate falls in the KPZ universality class. Our demonstration relies on a direct measurement of KPZ space-time scaling laws, combined with a theoretical microscopic analysis that consistently reveals the other key signatures of this universality class, together with the possible resilience of KPZ dynamics to the presence of space-time vortices. Our results highlight fundamental physical differences between out-of-equilibrium condensates and their equilibrium counterparts, and open a new paradigm for exploring universal behaviors in open systems.

Over the past decade, exciton-polaritons in semiconductor microcavities have attracted a great deal of interest as a driven-dissipative quantum fluid. These systems offer themselves as a versatile platform for performing Hamiltonian simulations with light, as well as for experimentally realizing nontrivial out-of-equilibrium phase transitions. In addition, polaritons exhibit a sizeable mutual interaction strength that opens up a whole range of possibilities in the context of quantum state generation. While squeezed light emission from polaritons has been reported previously, the granular nature of polaritons has not been observed to date. The latter capability is particularly attractive for realizing strongly correlated many-body quantum states of light on scalable arrays of coupled cavities. Here we demonstrate that by optically confining polaritons to a very small effective mode volume, one can reach the weak blockade regime, in which the nonlinearity turns strong enough to become significant at the few particle level, and thus produce a non-negligible antibunching in the emitted photons statistics. Our results act as a door opener for accessing the newly emerging field of quantum polaritonics, and as a proof of principle that optically confined exciton-polaritons can be considered as a realistic, new strategy to generate single photons., Comment: 12 pages, 10 figures

Gallium Arsenide and related compound semiconductors lie at the heart of optoelectronics and integrated laser technologies. Shaped at the micro and nano-scale, they allow strong interaction with quantum dots and quantum wells, and promise to result in stunning devices. However gallium arsenide optical structures presently exhibit lower performances than their silicon-based counterparts, notably in nanophotonics where the surface plays a chief role. Here we report on advanced surface control of miniature gallium arsenide optical resonators, using two distinct techniques that produce permanent results. One leads to extend the lifetime of free-carriers and enhance luminescence, while the other strongly reduces surface absorption originating from mid-gap states and enables ultra-low optical dissipation devices. With such surface control, the quality factor of wavelength-sized optical disk resonators is observed to rise up to six million at telecom wavelength, greatly surpassing previous realizations and opening new prospects for Gallium Arsenide nanophotonics.