Continuous mode cooling and phonon routers for phononic quantum networks

We study the implementation of quantum state transfer protocols in phonon networks, where in analogy to optical networks, quantum information is transmitted through propagating phonons in extended mechanical resonator arrays or phonon waveguides. We describe how the problem of a non-vanishing thermal occupation of the phononic quantum channel can be overcome by implementing optomechanical multi- and continuous mode cooling schemes to create a 'cold' frequency window for transmitting quantum states. In addition, we discuss the implementation of phonon circulators and switchable phonon routers, which rely on strong coherent optomechanical interactions only, and do not require strong magnetic fields or specific materials. Both techniques can be applied and adapted to various physical implementations, where phonons coupled to spin or charge based qubits are used for on-chip networking applications.Comment: 33 pages, 8 figures. Final version, a few minor changes and updated reference

Nitrogen uptake and rate-limiting step in low-temperature nitriding of iron

Recently, a method to nitride iron in NH3 ambients at low temperature (225-350 degrees C) has been developed. In this method, the Fe is covered with a thin (similar to 40 nm) Ni layer, which acts as a catalyst for the nitriding process. From experiments, in which the amount of nitrogen uptake is measured as a function of nitriding time, it is concluded that the decomposition of NH3 at the Ni surface contains the rate-limiting step in this low-temperature nitriding process. From a model calculation, it is further concluded that the reaction step NH3-->NH2+H at the Ni surface is the rate-limiting step with an activation energy of similar to 1.5 eV

Morphological evolution of pulsed laser deposited ZrO2 thin films

Morphological evolution of ZrO2 thin films deposited during pulsed laser deposition of Zr in O2 atmosphere has been experimentally studied at two different film deposition temperatures, 300 and 873 K. The roughness exponent, , the growth exponent, , the coarsening exponent, 1/z, and the exponent defining the evolution of the characteristic wavelength of the surface, p, for depositions at 300 K amounted to = 1.00.1, = 0.40.1, 1/z= 0.340.03, and p= 0.490.03, whereas for depositions carried out at 873 K amounted to = 0.30.3, = 0.40.2, and 1/z= 0.00.2. Experimental error becomes important due to the flat morphology of the films inherent to the deposition technique. The change in the surface topography with the film temperature has been studied with the help of a simple Monte Carlo model which indicates the existence of two different growth regimes: a shadowing dominated growth, occurring at low temperatures, characterized by calculated values = 1.000.04, = 0.500.04, p= 0.460.01, and 1/z= 0.350.02 and a diffusion dominated growth that takes place at high temperatures as well as at low deposition rates, characterized by calculated values = 0.150.08, = 0.330.04, and 1/z= 0.330.07. The good agreement obtained between the experimental and simulated parameters is discussed within the frame of the general characteristics of the deposition method.Universidad Nacional Autónoma de México-PAPIIT-IN107808Consejo Nacional de Ciencia y Tecnología de México-CONACyT-50203-FMinisterio de Ciencia, Innovación y Universidades de España-MAT 2007-65764, PIE 200960I132 y CONSOLIDER INGENIO 2010-CSD2008-00023Junta de Andalucía-TEP2275 y P07-FQM-0329

Polypeptide-grafted macroporous polyHIPE by surface-initiated N-Carboxyanhydride (NCA) polymerization as a platform for bioconjugation

A new class of functional macroporous monoliths from polymerized high internal phase emulsion (polyHIPE) with tunable surface functional groups was developed by direct polypeptide surface grafting. In the first step, amino-functional polyHIPEs were obtained by the addition of 4-vinylbenzyl or 4-vinylbenzylphthalimide to the styrenic emulsion and thermal radical polymerization. The obtained monoliths present the expected open-cell morphology and a high surface area. The incorporated amino group was successfully utilized to initiate the ring-opening polymer- ization of benzyl-L-glutamate N-carboxyanhydride (BLG NCA) and benzyloxycarbonyl-L-lysine (Lys(Z)) NCA, which resulted in a dense homogeneous coating of polypeptides throughout the internal polyHIPE surfaces as confirmed by SEM and FTIR analysis. The amount of polypeptide grafted to the polyHIPE surfaces could be modulated by varying the initial ratio of amino acid NCA to amino-functional polyHIPE. Subsequent removal of the polypeptide protecting groups yielded highly functional polyHIPE-g-poly(glutamic acid) and polyHIPE-g- poly(lysine). Both types of polypeptide-grafted monoliths responded to pH by changes in their hydrohilicity. The possibility to use the high density of function (−COOH or −NH2) for secondary reaction was demonstrated by the successful bioconjugation of enhanced green fluorescent protein (eGFP) and fluorescein isocyanate (FITC) on the polymer 3D-scaffold surface. The amount of eGFP and FITC conjugated to the polypeptide-grafted polyHIPE was significantly higher than to the amino- functional polyHIPE, signifying the advantage of polypeptide grafting to achieve highly functional polyHIPEs

Discovery of a low-mass companion inside the debris ring surrounding the F5V star HD 206893

Aims: Uncovering the ingredients and the architecture of planetary systems is a very active field of research that has fuelled many new theories on giant planet formation, migration, composition, and interaction with the circumstellar environment. We aim at discovering and studying new such systems, to further expand our knowledge of how low-mass companions form and evolve. Methods: We obtained high-contrast H-band images of the circumstellar environment of the F5V star HD 206893, known to host a debris disc never detected in scattered light. These observations are part of the SPHERE High Angular Resolution Debris Disc Survey (SHARDDS) using the InfraRed Dual-band Imager and Spectrograph (IRDIS) installed on VLT/SPHERE. Results: We report the detection of a source with a contrast of 3.6 × 10[SUP]-5[/SUP] in the H-band, orbiting at a projected separation of 270 milliarcsec or 10 au, corresponding to a mass in the range 24 to 73 M[SUB]Jup[/SUB] for an age of the system in the range 0.2 to 2 Gyr. The detection was confirmed ten months later with VLT/NaCo, ruling out a background object with no proper motion. A faint extended emission compatible with the disc scattered light signal is also observed. Conclusions: The detection of a low-mass companion inside a massive debris disc makes this system an analog of other young planetary systems such as β Pictoris, HR 8799 or HD 95086 and requires now further characterisation of both components to understand their interactions.Peer reviewe

Variations in 123I-metaiodobenzylguanidine (MIBG) late heart mediastinal ratios in chronic heart failure: a need for standardisation and validation

BACKGROUND: There is lack of validation and standardisation of acquisition parameters for myocardial (123)I-metaiodobenzylguanidine (MIBG). This lack of standardisation hampers large scale implementation of (123)I-MIBG parameters in the evaluation of patients with chronic heart failure (CHF). METHODS: In a retrospective multi-centre study (123)I-MIBG planar scintigrams obtained on 290 CHF patients (82% male; 58% dilated cardiomyopathy; New York Heart Association [NYHA classification] > I) were reanalysed to determine the late heart-to-mediastinum ratio (H/M). RESULTS: There was a large variation in acquisition parameters. Multivariate forward stepwise regression showed that a significant proportion (31%, p < 0.001) of the variation in late H/M could be explained by a model containing patient-related variables and acquisition parameters. Left ventricular ejection fraction (p < 0.001), type of collimation (p < 0.001), acquisition duration (p = 0.001), NYHA class (p = 0.028) and age (p = 0.034) were independent predictors of late H/M. CONCLUSIONS: Acquisitions parameters are independent contributors to the variation of semi-quantitative measurements of cardiac (123)I-MIBG uptake. Improved standardisation of cardiac (123)I-MIBG imaging parameters would contribute to increased clinical applicability for this procedur

The Giant Radio Array for Neutrino Detection (GRAND) Project

The GRAND project aims to detect ultra-high-energy neutrinos, cosmic rays and gamma rays, with an array of 200,000 radio antennas over 200,000km$^2$, split into ∼20 sub-arrays of ∼10,000km$^2$ deployed worldwide. The strategy of GRAND is to detect air showers above 10$^{17}$eV that are induced by the interaction of ultra-high-energy particles in the atmosphere or in the Earth crust, through its associated coherent radio-emission in the 50−200MHz range. In its final configuration, GRAND plans to reach a neutrino-sensitivity of ∼10$^{−10}$GeV cm$^{−2}$s$^{−1}$sr$^{−1}$ above 5×10$^{17}$eV combined with a sub-degree angular resolution. GRANDProto300, the 300-antenna pathfinder array, is planned to start data-taking in 2021. It aims at demonstrating autonomous radio detection of inclined air-showers, and study cosmic rays around the transition between Galactic and extra-Galactic sources. We present preliminary designs and simulation results, plans for the ongoing, staged approach to construction, and the rich research program made possible by the proposed sensitivity and angular resolution

The Giant Radio Array for Neutrino Detection (GRAND) Project

The GRAND project aims to detect ultra-high-energy neutrinos, cosmic rays and gamma rays, with an array of 200,000 radio antennas over 200,000km$^2$, split into ∼20 sub-arrays of ∼10,000km$^2$ deployed worldwide. The strategy of GRAND is to detect air showers above 10$^{17}$\,eV that are induced by the interaction of ultra-high-energy particles in the atmosphere or in the Earth crust, through its associated coherent radio-emission in the 50−200\,MHz range. In its final configuration, GRAND plans to reach a neutrino-sensitivity of ∼10$^{−10}$GeVcm$^{−2}$s$^{−1}$sr$^{−1}$ above 5×10$^{17}$\,eV combined with a sub-degree angular resolution. GRANDProto300, the 300-antenna pathfinder array, is planned to start data-taking in 2021. It aims at demonstrating autonomous radio detection of inclined air-showers, and study cosmic rays around the transition between Galactic and extra-Galactic sources. We present preliminary designs and simulation results, plans for the ongoing, staged approach to construction, and the rich research program made possible by the proposed sensitivity and angular resolution

Self-trigger radio prototype array for GRAND

The GRANDProto300 (GP300) array is a pathfinder for the Giant Radio Array for Neutrino Detection (GRAND) project. The deployment of the array, consisting of 300 antennas, will start in 2021 in a radio-quiet area of ~200 km2 near Lenghu (~3000 m a.s.l.) in China. Serving as a test bench, the GP300 array is expected to pioneer techniques of autonomous radio detection including identification and reconstruction of nearly horizontal cosmic-ray (CR) air showers. In addition, the GP300 array is at a privileged position to study the transition between Galactic and extragalactic origins of cosmic rays, due to its large effective area and the precise measurements of both energy and mass composition for CRs with energies ranging from 30 PeV to 1 EeV. Using the GP300 array we will also investigate the potential sensitivity for radio transients such as Giant Radio Pulses and Fast Radio Bursts in the 50-200 MHz range

Investigation of the effect of temper rolling on the texture evolution and mechanical behavior of IF steels using multiscale simulation

The main objective of this study is to simulate texture and deformation during the temper-rolling process. To this end, a rate-independent crystal plasticity model, based on the self-consistent scale-transition scheme, is adopted to predict texture evolution and deformation heterogeneity during temper-rolling process. For computational efficiency, a decoupled analysis is considered between the polycrystalline plasticity model and the finite element analysis for the temper rolling. The elasto-plastic finite element analysis is first carried out to determine the history of velocity gradient during the numerical simulation of temper rolling. The thus calculated velocity gradient history is subsequently applied to the polycrystalline plasticity model. By following some appropriately selected strain paths (i.e., streamlines) along the rolling process, one can predict the texture evolution of the material at the half thickness of the sheet metal as well as other parameters related to its microstructure. The numerical results obtained by the proposed strategy are compared with experimental data in the case of IF steels.French program “Investment in the future” operated by the National Research Agency (ANR)-11-LABX-0008-01, LabEx DAMAS (LST)