Vortex conveyor belt for matter-wave coherent splitting and interferometry

We numerically study a matter wave interferometer realized by splitting a trapped Bose-Einstein condensate with phase imprinting. We show that a simple step-like imprinting pattern rapidly decays into a string of vortices that can generate opposite velocities on the two halves of the condensate. We first study in detail the splitting and launching effect of these vortex structures, whose functioning resembles the one of a conveyor belt, and we show that the initial exit velocity along the vortex conveyor belt can be controlled continuously by adjusting the vortex distance. We finally characterize the complete interferometric sequence, demonstrating how the phase of the resulting interference fringe can be used to measure an external acceleration. The proposed scheme has the potential to be developed into compact and high precision accelerometers

Non-equilibrium quantum thermodynamics in ultracold atomic mixtures

This thesis is devoted to the experimental study of non-equilibrium quantum thermodynamics. In it, I describe the design and development of a system that allowed our team to perform pioneering experiments on non-equilibrium quantum gases close to the absolute zero. Using such a system, we achieved the realization of long-lived non-equilibrium Bose-Einstein condensates with condensed fractions exceeding those of equilibrium samples with the same parameters. We achieved this by immersing an ultracold Bose gas of 87Rb in a cloud of 39K with a temperature difference of four orders of magnitude, providing a controlled source of dissipation. Then, I report the state of the current project: the implementation of a single-atom quantum engine using a single 41K atom as the working fluid and an ultracold cloud of 87Rb as the thermal bath. Lastly, I show that it is possible to realize the FrenkelKontorova model using a system of interacting Rydberg-dressed atoms placed in an optical lattice. To do so, I studied the properties of the ground states of the system and its phonon spectra for different sets of parameters by simulating the cited system

Non-Volatile Photonic Memory Based on a SAHAS Configuration

[EN] The non-volatile memory is a crucial functionality for a wide range of applications in photonic integrated circuits, however, it still poses a challenge in silicon photonic technology. This problem has been overcome in the microelectronic industry by using SONOS (silicon-oxide-nitride-oxide-silicon) memory cells, in which the non-volatility is enabled by a dielectric trapping layer such as silicon nitride. Analogously, in this work, a similar approach in which the nitride has been replaced by a hafnium oxide layer, named as SAHAS configuration, is proposed for enabling a programmable erasable photonic memory fully compatible with the silicon platform. The structure features an efficient performance with writing and erasing times of 100 mu s, retention times over 10 years and energy consumption in the pJ range, which improve the current SONOS or floating gate based photonic approaches that exploit the plasma dispersion effect in silicon. The proposed non-volatile photonic memory device shows an extinction ratio above 12 dB and insertion losses below 1 dB in a compact footprint. In addition, because the memory is optically read, ultrafast access times in the picosecond range are also achieved.This work was supported in part by Ministerio de Economia y Competitividad (MINECO/FEDER, UE) (TEC2016-76849), in part by Generalitat Valenciana (PROMETEO/2019/123), in part by Ministerio de Ciencia e Innovacion (MINECO/FEDER, UE) (PID2019-111460GB-I00, FPU17/04224), and in part by Universitat Politecnica de Valencia (FPI Grant).Olivares-Sánchez-Mellado, I.; Parra Gómez, J.; Sanchis Kilders, P. (2021). Non-Volatile Photonic Memory Based on a SAHAS Configuration. IEEE Photonics Journal. 13(2):1-9. https://doi.org/10.1109/JPHOT.2021.3060144S1913

Potential Accumulative Effect of the Herbicide Glyphosate on Glyphosate-Tolerant Maize Rhizobacterial Communities over a Three-Year Cultivation Period

BACKGROUND: Glyphosate is a herbicide that is liable to be used in the extensive cultivation of glyphosate-tolerant cultivars. The potential accumulation of the relative effect of glyphosate on the rhizobacterial communities of glyphosate-tolerant maize has been monitored over a period of three years. METHODOLOGY/PRINCIPAL FINDINGS: The composition of rhizobacterial communities is known to vary with soil texture, hence, the analyses have been performed in two agricultural fields with a different soil texture. The accumulative effects of glyphosate have been monitored by means of high throughput DNA pyrosequencing of the bacterial DNA coding for the 16S rRNA hypervariable V6 region from rhizobacterial communities. The relative composition of the rhizobacterial communities does vary in each field over the three-year period. The overall distribution of the bacterial phyla seems to change from one year to the next similarly in the untreated and glyphosate-treated soils in both fields. The two methods used to estimate bacterial diversity offered consistent results and are equally suitable for diversity assessment. CONCLUSIONS/SIGNIFICANCE: The glyphosate treatment during the three-year period of seasonal cultivation in two different fields did not seem to significantly change the maize rhizobacterial communities when compared to those of the untreated soil. This may be particularly relevant with respect to a potential authorisation to cultivate glyphosate-tolerant maize in the European Union

Gremio, democracia y asociatividad: el Colegio de Periodistas de Chile ante los comunicadores de hoy.

La baja asociatividad que presenta el Colegio de Periodistas, plantea dudas respecto a la real vigilancia democrática e injerencia en la vida pública de un gremio debilitado. En efecto, la asociatividad de los profesionales es baja en comparación a gremios similares; registrando sólo un 2,9% del total de egresados en la Octava Región durante los últimos cinco años, cifra similar al resto del país. Esta realidad implica una responsabilidad de la propia entidad, por cuanto el colegio desconoce el creciente protagonismo de los periodistas en el ámbito organizacional y corporativo –de hecho un 64% de los profesionales de la región se desempeña en estas áreas-, existiendo una evidente despreocupación por cautivar y comprometer a aquéllos no vinculados al periodismo tradicional. En síntesis, la crisis de representatividad en que se encuentran los periodistas cuestiona su rol social, el carácter del Colegio y -más aún- la formación profesional misma.The low associability around Colegio de Periodistas, states serious doubts about the real democratic vigilance and influence into the public life of a weakened guild. In fact, the journalists’ associability is down compared to similar guilds, whit just a 2.9% to the total of graduates in the Eighth Region during last five years, similar quantity in the rest of the country. This reality implicates a responsibility from the Colegio de Periodistas, because the entity don’t know the journalists’ increasing leading into the organizational and corporative area – in fact, a 64% from the Eighth Region professionals work on these areas- showing an evident unconcern to charm and compromise to those non-linked at the traditional journalism. In summary, the journalists’ representatively crisis questions their social role, Colegio de Periodistas’ character and more over professional formation itself

Realizing the Frenkel-Kontorova model with Rydberg-dressed atoms

We propose a method to realize the Frenkel-Kontorova model using an array of Rydberg dressed atoms. Our platform can be used to study this model with a range of realistic interatomic potentials. In particular, we concentrate on two types of interaction potentials: a springlike potential and a repulsive long-range potential. We numerically calculate the phase diagram for such systems and characterize the Aubry-like and commensurate-incommensurate phase transitions. Experimental realizations of this system that are possible to achieve using current technology are discussed.Comment: Added a few reference

Poultices Generated Mechanically with Compressed Air: “Gunpoint Mix System” Characterization and Properties. Comparison with “Handmade” Poultices

The authors have developed an automated method Gunpoint mix hQps youtu be 4uXC_OoP7EM for the manufacture of poultrices The proper es of the cellulose poultrices placed manually with those placed with the GunPoint Mix method applied on stone substrates of known characteris cs are compared Arbocel BWW40 is used in both cases The physical parameters of the cellulose the microscopic texture the absorp on and desorp on proper es the penetra on of a consolida ng product and the ease of cleaning are measured The main advantage of the Gunpoint mix method lies in the speed of the applica on that allows a very exact control of the applica on mes Given its good adhesion it can be applied with the same speed in the roof and top of the vaults upside down without the risk of landslides The water parameters of each type of poultrice provide informa on to the restorer to decide on what type of treatment is more appropriate to use a handmade poultrice or a Gunpoint mix poultric

Ultra-compact non-volatile Mach-Zehnder switch enabled by a high-mobility transparent conducting oxide

[EN] Compact and broadband non-volatile silicon devices are mainly absorption based. Hence, access to low-loss non-volatile phase shifters is still a challenge. Here, this problem is addressed by using a high-mobility transparent conducting oxide such as cadmium oxide as a floating gate in a flash-like structure. This structure is integrated in a Mach¿Zehnder interferometer switch. Results show an active length of only 30 µm to achieve a ¿¿ phase shift. Furthermore, an extinction ratio of 20 dB and insertion loss as low as 1 dB may be attained. The device shows an optical broadband response and can be controlled with low-power pulses in the nanosecond range. These results open a new, to the best of our knowledge, way for enabling compact silicon-based phase shifters with non-volatile performance.Ministerio de Economia y Competitividad (TEC2016-76849); Generalitat Valenciana (PROMETEO/2019/123); Ministerio de Ciencia, Innovacion y Universidades (FPU17/04224).Parra Gómez, J.; Olivares-Sánchez-Mellado, I.; Ramos, F.; Sanchis Kilders, P. (2020). Ultra-compact non-volatile Mach-Zehnder switch enabled by a high-mobility transparent conducting oxide. Optics Letters. 45(6):1503-1506. https://doi.org/10.1364/OL.388363S1503150645

Toward Nonvolatile Switching in Silicon Photonic Devices

[EN] Nonvolatile switching is still a missing functionality in current mainstream silicon photonics complementary metal-oxide-semiconductor platforms. Fundamentally, nonvolatile switching stands for the ability to switch between two or more photonic states reversibly without needing additional energy to hold each state. Therefore, such a feature may push one step further the potential of silicon photonics by offering new ways of achieving photonic reconfigurability with ultrasmall energy consumption. Here, a detailed review of current developments that enable nonvolatile switching in silicon photonic waveguide devices is provided. Nonvolatility is successfully demonstrated either based on device engineering or by hybrid integration of silicon waveguides with materials exhibiting unique optical properties. Furthermore, several approaches with high potential for evolving toward a nonvolatile behavior with enhanced performance are also being explored. In most cases, many development steps are still necessary to ensure reliable devices. However, this research field is expected to progress in the coming years boosted by current and emerging applications benefiting from such functionality, such as new paradigms for photonic computing or advanced reconfigurable circuits for programmable photonic systems.This work was supported by Ministerio de Economia y Competitividad (MINECO) (TEC2016-76849); Ministerio de Ciencia e Innovacion (PID2019-111460GB-I00, FPU17/04224); and Generalitat Valenciana (PROMETEO/2019/123).Parra Gómez, J.; Olivares-Sánchez-Mellado, I.; Brimont, ACJ.; Sanchis Kilders, P. (2021). Toward Nonvolatile Switching in Silicon Photonic Devices. Laser & Photonics Review. 15(6):1-18. https://doi.org/10.1002/lpor.20200050111815

Adaptation of Didactical Suitability criteria for evaluating mathematics educational videos available on Internet

II Congreso Internacional Virtual sobre el Enfoque Ontosemiótico del Conocimiento y la Instrucción Matemáticos (CIVEOS-2), 23-26 de marzo de 2017. [http://enfoqueontosemiotico.ugr.es/]El creciente uso de videos educativos de matemáticas (VEM) disponibles en Internet, hace que su impacto en el aprendizaje de la matemática sea cada vez mayor, independientemente de los objetivos institucionales. Para los estudiantes los videos se están transformando en una fuente confiable de información matemática. Sin embargo, no contamos con juicios educativos sobre su calidad, por lo que consideramos que es necesario valorarlos privilegiando su aproximación didáctica y su contenido matemático. Para llevar a cabo tal valoración, consideramos las seis dimensiones que conforman la noción de idoneidad didáctica propuesta por el EOS, las cuales, mediante una adaptación, proporcionan indicadores medibles que son base de diversos modelos, sustentados en la lógica difusa, los cuales permiten comparar estas producciones. En el presente trabajo, mostramos las consideraciones para dicha adaptación.The increasing use of educational mathematics videos (EMV) available on the Internet makes its impact on learning mathematics increasing, regardless of the institutional objectives. For students videos are becoming a dependable source of mathematical information; however, we do not count with educational judgments about their quality. It is therefore necessary to value them by giving priority to their didactic approach and mathematical content. In order to carry out such assessment, we consider the six dimensions that constitute the notion of didactic suitability proposed by the EOS. Through an adaptation, they provide measurable indicators based on different models, supported by the fuzzy logic, which allow comparing these productions. In the present work, we show the criteria used to carry out this adaptation