Three-antenna two-dimensional imaging correlation radiometer: concept and preliminary results

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The Young Modulus of Black Strings and the Fine Structure of Blackfolds

We explore corrections in the blackfold approach, which is a worldvolume theory capturing the dynamics of thin black branes. The corrections probe the fine structure of the branes, going beyond the approximation in which they are infinitely thin, and account for the dipole moment of worldvolume stress-energy as well as the internal spin degrees of freedom. We show that the dipole correction is induced elastically by bending a black brane. We argue that the long-wavelength linear response coefficient capturing this effect is a relativistic generalization of the Young modulus of elastic materials and we compute it analytically. Using this we draw predictions for black rings in dimensions greater than six. Furthermore, we employ our corrected blackfold equations to various multi-spinning black hole configurations in the blackfold limit, finding perfect agreement with known analytic solutions.Comment: v1: 28 pages + appendices. v2: Important sign corrections in sec. 3. Other minor correction

Chemistry on quantum computers with virtual quantum subspace expansion

Several novel methods for performing calculations relevant to quantum chemistry on quantum computers have been proposed but not yet explored experimentally. Virtual quantum subspace expansion [T. Takeshita et al., Phys. Rev. X 10, 011004 (2020)] is one such algorithm developed for modeling complex molecules using their full orbital space and without the need for additional quantum resources. We implement this method on the IBM Q platform and calculate the potential energy curves of the hydrogen and lithium dimers using only two qubits and simple classical post-processing. A comparable level of accuracy would require twenty qubits with previous approaches. We also develop an approach to minimize the impact of experimental noise on the stability of a generalized eigenvalue problem that is a crucial component of the algorithm. Our results demonstrate that virtual quantum subspace expansion works well in practice

La place de l'estime de soi globale et physique dans la construction identitaire de l'adolescent

International audienceA partir d'un recueil de données réalisé auprès de plus de 500 collégien(ne)s, nous proposons d'évaluer l'estime de soi dans les domaines global et physique. En effet, de profondes modifications physiques, psychologiques et sociales interviennent à l'adolescence et l'objet de cette recherche est de préciser les répercussions possibles de ces transformations physiques et psychologiques sur l'estime de soi, en fonction de l'âge et du genre. À un moment où le corps se métamorphose et où certaines de ces transformations physiques peuvent être délicates à vivre, l'adolescent se focalise sur son image corporelle. La perception du corps joue donc un rôle essentiel dans la construction de l'estime de soi, et plus particulièrement à l'adolescence (Bruchon-Schweitzer, 1990). Depuis près de 20 ans, le concept de soi physique émerge comme une construction essentielle et constitutive de l'identité, particulièrement dans nos cultures occidentales qui attachent beaucoup d'importance à l'apparence et aux capacités physiques. En effet, par son apparence, ses attributs corporels et ses compétences physiques, le sujet étaye son soi physique, et dans certaines conditions renforce son estime de soi globale (Bégarie et al., 2011).L'objectif de cette communication consiste à confirmer l'importance de cette dimension physique du soi auprès d'un échantillon d'adolescents tout-venants. Dans une perspective développementale, il s'agit de montrer que les niveaux d'estime de soi globale et physique chez ces adolescents évoluent en fonction du genre et de l'âge. Dans cette optique, nous avons mené une étude empirique sur 579 collégien(ne)s de la région Midi Pyrénées, âgés de 11 à 17 ans (M = 13,34 ; ET = 1,20) qui ont renseigné l'échelle de Rosenberg (1965) et l'Inventaire de Soi Physique de Ninot, Delignières et Fortes (2000). Nos résultats (Fourchard & Courtinat-Camps, 2013) confirment ceux des recherches antérieures (Bolognini et al., 1996 ; Seidah et al., 2004) : les filles obtiennent des niveaux d'estime de soi physique et globale plus faibles que les garçons. De plus, les scores d'estime de soi diminuent avec l'âge avec une baisse plus marquée entre 12 et 13 ans, c'est-à-dire en pleine transformation corporelle et psychologique. La discussion s'oriente ensuite sur l'interprétation des différences de genre dans l'évaluation de l'estime de soi globale et physique et sur l'interprétation de différences au cours du développement de la personne

Antimagnets: Controlling magnetic fields with superconductor-metamaterial hybrids

Magnetism is very important in science and technology, from magnetic recording to energy generation to trapping cold atoms. Physicists have managed to master magnetism - to create and manipulate magnetic fields- almost at will. Surprisingly, there is at least one property which until now has been elusive: how to 'switch off' the magnetic interaction of a magnetic material with existing magnetic fields without modifying them. Here we introduce the antimagnet, a design to conceal the magnetic response of a given volume from its exterior, without altering the external magnetic fields, somehow analogous to the recent theoretical proposals for cloaking electromagnetic waves with metamaterials. However, different from these devices requiring extreme material properties, our device is feasible and needs only two kinds of available materials: superconductors and isotropic magnetic materials. Antimagnets may have applications in magnetic-based medical techniques such as MRI or in reducing the magnetic signature of vessels or planes.Comment: 14 pages, 4 figure

Designing oxynitride nanostructured thin films to enhance europium white light emission for efficient solid state emitters

CLEO®/Europe-EQEC 2015, Munich (ICM), Germany, June 21st, - 25th, 2015; http://2015.cleoeurope.org/In the present work we study the visible light emission of europium (Eu) ions embedded in two different matrices (amorphous aluminum oxide (a-Al2O3) and ceramic SiAlON) as a function of the Eu distribution and concentration. Eu-doped thin films were produced using the pulsed laser deposition technique by the alternating ablation of the matrix target and the Eu target; as a result nanostructured Eu-doped multilayers were formed. The Eu in-depth distribution was modified by varying the host inter-layer thickness, which ranged from 1 to 15 nm, and the Eu content per layer was modified by varying the number of pulses on the Eu target. Under UV excitation (355 nm), the as-deposited films of both matrices showed a broadband emission (FWHM ¿200 nm), that has been related to the superposition of the 5d levels to the 4f levels of the Eu2+, which is rarely found in pure oxides. This broad emission was further enhanced keeping the same spectral distribution upon annealing treatments up to 500 oC for the a-Al2O3 (Fig. 1a) and 700 oC for the SiAlON (Fig. 1c). However for samples with higher Eu content and at the higher annealing temperatures the spectral shape emission changed and the emission spectra showed narrow and well-defined emission peaks. These have been identified as resulting from the 4f ¿ 4f transitions of Eu3+ (Fig. 1b). Therefore, it has been found that two distinct and efficient Eu-related emissions can be obtained by a suitable design of the Eu distribution and concentration. This is due to a change of oxidation state of Eu in the films, which will be discussed. These Eu-doped films have a high potential for the development of either solid state lighting LEDs with broadband emission, or integrated lasers with narrow emission lines. Acknowledgements. This work has been financially supported by the Spanish Ministry of Economy and Competitiveness through the project TEC2012_38901-C02-01. I.C. acknowledges the financial support through JAE-Pre-2011_00578. A.M. acknowledges the financial support through BES-2013-062593.This work has been financially supported by the Spanish Ministry of Economy and Competitiveness through the project TEC2012_38901-C02-01. I.C. acknowledges the financial support through JAE-Pre-2011_00578. A.M. acknowledges the financial support through BES-2013-062593.Peer Reviewe