Results for "É . Dumur"

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A V-shape superconducting artificial atom based on two inductively coupled transmonsJan 20 2015May 07 2015Circuit quantum electrodynamics systems are typically built from resonators and two-level artificial atoms, but the use of multi-level artificial atoms instead can enable promising applications in quantum technology. Here we present an implementation ... More
Unidirectional Distributed Acoustic Reflection Transducers for Quantum ApplicationsMay 08 2019Recent significant advances in coupling superconducting qubits to acoustic wave resonators has led to demonstrations of quantum control of surface and bulk acoustic resonant modes as well Wigner tomography of quantum states in these modes. These advances ... More
Fast high fidelity quantum non-demolition qubit readout via a non-perturbative cross-Kerr couplingMay 01 2019May 02 2019Qubit readout is an indispensable element of any quantum information processor. In this work we propose an original coupling scheme between qubit and cavity mode based on a non-perturbative cross-Kerr interaction. It leads to an alternative readout mechanism ... More
Phonon-mediated quantum state transfer and remote qubit entanglementMar 13 2019Phonons, and in particular surface acoustic wave phonons, have been proposed as a means to coherently couple distant solid-state quantum systems. Recent experiments have shown that superconducting qubits can control and detect individual phonons in a ... More
Is motion under the conservative self-force in black hole spacetimes an integrable Hamiltonian system?Mar 16 2015A point-like object moving in a background black hole spacetime experiences a gravitational self-force which can be expressed as a local function of the object's instantaneous position and velocity, to linear order in the mass ratio. We consider the worldline ... More
Ultrafast QND measurements based on diamond-shape artificial atomFeb 15 2013We propose a Quantum Non Demolition (QND) read-out scheme for a superconducting artificial atom coupled to a resonator in a circuit QED architecture, for which we estimate a very high measurement fidelity without Purcell effect limitations. The device ... More
Cosmological backreaction and spatially averaged spatial curvatureSep 11 2008It has been suggested that the accelerated expansion of the Universe is due to backreaction of small scale density perturbations on the large scale spacetime geometry. While evidence against this suggestion has accumulated, it has not yet been definitively ... More
Hawking radiation in a two-component Bose-Einstein condensateJul 10 2013Oct 03 2013We consider a simple realization of an event horizon in the flow of a one-dimensional two-component Bose-Einstein condensate. Such a condensate has two types of quasiparticles; In the system we study, one corresponds to density fluctuations and the other ... More
Kerr non-linearity in a superconducting Josephson metamaterialJul 04 2018Jul 05 2018We present a detailed experimental and theoretical analysis of the dispersion and non-linear Kerr frequency shifts of plasma modes in a one-dimensional Josephson junction chain containing 500 SQUIDs in the regime of weak nonlinearity. The measured low-power ... More
The size and structure of the spheroid of IC 1613Feb 19 2007Nearby galaxies, spirals as well as irregulars, have been found to be much larger than previously believed. The structure of the huge spheroid surrounding dwarf galaxies could give clues to their past gravitational history. Thanks to wide field imagers, ... More
Post-1-Newtonian tidal effects in the gravitational waveform from binary inspiralsJan 09 2011The gravitational wave signal from an inspiralling binary neutron star system will contain detailed information about tidal coupling in the system, and thus, about the internal physics of the neutron stars. To extract this information will require highly ... More
Gravitomagnetic resonant excitation of Rossby modes in coalescing neutron star binariesJan 07 2006Feb 02 2007In coalescing neutron star binaries, r-modes in one of the stars can be resonantly excited by the gravitomagnetic tidal field of its companion. This post-Newtonian gravitomagnetic driving of these modes dominates over the Newtonian tidal driving previously ... More
Prethermalization in a quenched one-dimensional quantum fluid of light: Intrinsic limits to the coherent propagation of a light beam in a nonlinear optical fiberOct 19 2015Jan 11 2016We study the coherence properties of a laser beam after propagation along a one-dimensional lossless nonlinear optical waveguide. Within the paraxial, slowly-varying-envelope, and single-transverse-mode approximations, the quantum propagation of the light ... More
Propagation of a quantum fluid of light in a cavityless nonlinear optical medium: General theory and response to quantum quenchesDec 17 2014Sep 16 2015Making use of a generalized quantum theory of paraxial light propagation where the radiation-axis and the temporal coordinates play exchanged roles, we discuss the potential of bulk nonlinear optical media in cavityless configurations for quantum statistical ... More
Primordial non-Gaussianities in single field inflationary models with non-trivial initial statesOct 16 2013Sep 17 2014We compute the non-Gaussianities that arise in single field, slow roll inflationary models arising from arbitrary homogeneous initial states, as well as subleading contributions to the power spectrum. Non Bunch-Davies vacuum initial states can arise if ... More
Static Self-Forces in a Five-Dimensional Black Hole SpacetimeApr 17 2015Nov 18 2015We obtain the electric field and scalar field for a static point charge in closed form in the 5D Schwarzschild-Tangherlini black hole spacetime. We then compute the static self-force in each of these cases by assuming that the appropriate singular field ... More
Optomechanical signature of a frictionless flow of superfluid lightMay 09 2014May 14 2015We propose an experimental setup that should make it possible to reveal the frictionless flow of a superfluid of light from the suppression of the drag force that it exerts onto a material obstacle. In the paraxial-propagation geometry considered here, ... More
Feed drive modelling for the simulation of tool path tracking in multi-axis High Speed MachiningJul 16 2011Within the context of High Speed Machining, it is essential to manage the trajectory generation to achieve both high surface quality and high productivity. As feed drives are one part of the set Machine tool - Numerical Controller, it is necessary to ... More
High-performance NC for high-speed machining by means of polynomial trajectoriesSep 15 2013This paper summarises works carried out for defining tool trajectory formats well adapted to High Speed Machining (HSM). Advantages in using native polynomial formats, calculated directly from the CAD model, are highlighted. In particular, polynomial ... More
Model-based versus model-free control designs for improving microalgae growth in a closed photobioreactor: Some preliminary comparisonsMay 10 2016May 11 2016Controlling microalgae cultivation, i.e., a crucial industrial topic today, is a challenging task since the corresponding modeling is complex, highly uncertain and time-varying. A model-free control setting is therefore introduced in order to ensure a ... More
Fast high fidelity quantum non-demolition qubit readout via a non-perturbative cross-Kerr couplingMay 01 2019Qubit readout is an indispensable element of any quantum information processor. In this work we propose an original coupling scheme between qubit and cavity mode based on a non-perturbative cross-Kerr interaction. It leads to an alternative readout mechanism ... More
Astrometric Effects of a Stochastic Gravitational Wave BackgroundSep 21 2010Nov 27 2012A stochastic gravitational wave background causes the apparent positions of distant sources to fluctuate, with angular deflections of order the characteristic strain amplitude of the gravitational waves. These fluctuations may be detectable with high ... More
Postquench prethermalization in a disordered quantum fluid of lightDec 22 2017We study the coherence of a disordered and interacting quantum light field after propagation along a nonlinear optical fiber. Disorder is generated by a cross-phase modulation with a randomized auxiliary classical light field, while interactions are induced ... More
A study in sums of productsMay 09 2014Jan 17 2015We give a general version of cancellation in exponential sums that arise as sums of products of trace functions satisfying a suitable independence condition related to the Goursat-Kolchin-Ribet criterion, in a form that is easily applicable in analytic ... More
Luminosity distance in Swiss cheese cosmology with randomized voids and galaxy halosJul 16 2012We study the fluctuations in luminosity distance due to gravitational lensing produced both by galaxy halos and large scale voids. Voids are represented via a "Swiss cheese" model consisting of a \LambdaCDM Friedman-Robertson-Walker background in which ... More
Violating Bell's inequality with remotely-connected superconducting qubitsAug 09 2018Oct 17 2018Quantum communication relies on the efficient generation of entanglement between remote quantum nodes, due to entanglement's key role in achieving and verifying secure communications. Remote entanglement has been realized using a number of different probabilistic ... More
Observer dependence of angular momentum in general relativity and its relationship to the gravitational-wave memory effectNov 17 2014Feb 01 2016We define a procedure by which observers can measure a type of special-relativistic linear and angular momentum $(P^a, J^{ab})$ at a point in a curved spacetime using only the spacetime geometry in a neighborhood of that point. The method is chosen to ... More
Interplay of anisotropy and frustration: triple transitions in a triangular-lattice antiferromagnetDec 18 2008Aug 24 2009The classical Heisenberg antiferromagnet on a triangular lattice with the single-ion anisotropy of the easy-axis type is theoretically investigated. The mean-field phase diagram in an external magnetic field is constructed. Three finite-temperature Berezinskii-Kosterlitz-Thouless ... More
A four-dimensional description of five-dimensional N-brane modelsApr 14 2010Sep 03 2010We propose a new method for obtaining the four-dimensional effective gravitational theory for five-dimensional braneworld models with arbitrary numbers of branes in a low energy regime, based on a two-lengthscale expansion. The method is straightforward ... More
Gravitational Interactions in a General Multibrane ModelSep 23 2010Jan 26 2011The gravitational interactions of the four-dimensional effective theory describing a general $N$-brane model in five dimensions without radion stabilization are analyzed. Both uncompactified and orbifolded models are considered. The parameter space is ... More
Conserved charges of the extended Bondi-Metzner-Sachs algebraOct 12 2015Nov 14 2016Isolated objects in asymptotically flat spacetimes in general relativity are characterized by their conserved charges associated with the Bondi-Metzner-Sachs (BMS) group. These charges include total energy, linear momentum, intrinsic angular momentum ... More
Thermalization and Bose-Einstein condensation of quantum light in bulk nonlinear mediaMay 06 2016Jul 08 2016We study the thermalization and the Bose-Einstein condensation of a paraxial, spectrally narrow beam of quantum light propagating in a lossless bulk Kerr medium. The spatiotemporal evolution of the quantum optical field is ruled by a Heisenberg equation ... More
Properties of the giant HII regions and bar in the nearby spiral galaxy NGC5430Jun 08 2012In order to better understand the impact of the bar on the evolution of spiral galaxies, we measure the properties of giant HII regions and the bar in the SB(s)b galaxy NGC5430. We use two complementary data sets, both obtained at the Observatoire du ... More
The sliding-sum method for short exponential sumsJun 29 2013Aug 04 2015We introduce a method to estimate sums of oscillating functions on finite abelian groups over intervals or (generalized) arithmetic progressions, when the size of the interval is such that the completing techniques of Fourier analysis are barely insufficient ... More
Infrared variability of radio-loud narrow-line Seyfert 1 galaxiesJul 16 2018Most of the radio-loud narrow-line Seyfert 1 (NLS1) galaxies resemble compact steep-spectrum sources. However, the extremely radio-loud ones show blazar-like characteristics, like flat radio spectra, compact radio cores, substantial variability and high ... More
Four hot DOGs in the microwaveOct 14 2015Hot dust-obscured galaxies (hot DOGs) are a rare class of hyperluminous infrared galaxies identified with the Wide-field Infrared Survey Explorer (WISE) satellite. The majority of them is at high redshifts (z~2-3), at the peak epoch of star formation ... More
Stellar Populations in Barred GalaxiesOct 02 2009We developed an iterative technique to better characterize stellar populations and the central activity of barred galaxies using evolutionary synthesis codes and OASIS data. The case of NGC5430 is presented here. Our results are reinforcing the role played ... More
Dark Energy or Modified Gravity? An Effective Field Theory ApproachNov 29 2012Sep 23 2013We take an Effective Field Theory (EFT) approach to unifying existing proposals for the origin of cosmic acceleration and its connection to cosmological observations. Building on earlier work where EFT methods were used with observations to constrain ... More
Quantum fluctuations around black hole horizons in Bose-Einstein condensatesOct 20 2011Jan 18 2012We study several realistic configurations allowing to realize an acoustic horizon in the flow of a one dimensional Bose-Einstein condensate. In each case we give an analytical description of the flow pattern, of the spectrum of Hawking radiation and of ... More
Modification to the Luminosity Distance Redshift Relation in Modified Gravity TheoriesOct 02 2008Feb 11 2009We derive an expression for the luminosity distance as a function of redshift for a flat Robertson-Walker spacetime perturbed by arbitrary scalar perturbations possibly produced by a modified gravity theory with two different scalar perturbation potentials. ... More
The branching Brownian motion seen from its tipApr 19 2011Sep 28 2012It has been conjectured since the work of Lalley and Sellke (1987) that the branching Brownian motion seen from its tip (e.g. from its rightmost particle) converges to an invariant point process. Very recently, it emerged that this can be proved in several ... More
Polarization hydrodynamics in a one-dimensional polariton condensateSep 13 2013We study the hydrodynamics of a nonresonantly-pumped polariton condensate in a quasi-one-dimensional quantum wire taking into account the spin degree of freedom. We clarify the relevance of the Landau criterion for superfluidity in this dissipative two-component ... More
Wave pattern induced by a localized obstacle in the flow of a one-dimensional polariton condensateJul 06 2012Motivated by recent experiments on generation of wave patterns by a polariton condensate incident on a localized obstacle, we study the characteristics of such flows under the condition that irreversible processes play a crucial role in the system. The ... More
Self-forces on static bodies in arbitrary dimensionsFeb 29 2016We derive exact expressions for the scalar and electromagnetic self-forces and self-torques acting on arbitrary static extended bodies in arbitrary static spacetimes with any number of dimensions. Non-perturbatively, our results are identical in all dimensions. ... More
Self-forces in arbitrary dimensionsAug 25 2017Bodies coupled to electromagnetic or other long-range fields are subject to radiation reaction and other effects in which their own fields can influence their motion. Self-force phenomena such as these have been poorly understood for spacetime dimensions ... More
Computation of Relative Magnetic Helicity in Spherical CoordinatesJun 08 2018Magnetic helicity is a quantity of great importance in solar studies because it is conserved in ideal magneto-hydrodynamics. While many methods to compute magnetic helicity in Cartesian finite volumes exist, in spherical coordinates, the natural coordinate ... More
Quantum transport modeling of Fe/MgO/Fe magnetic tunnel junction with FeO$_{0.5}$ buffer layer: the effects of correlationsDec 06 2012We report \textit{ab initio} simulations of quantum transport properties of Fe/MgO/Fe trilayer structures with FeO$_{0.5}$ buffer iron oxide layer, where on-site Coulomb interaction is explicitly taken into account by local density approximation + Hubbard ... More
A Color Quantization Optimization Approach for Image Representation LearningNov 18 2017Nov 23 2017Over the last two decades, hand-crafted feature extractors have been used in order to compose image representations. Recently, data-driven feature learning have been explored as a way of producing more representative visual features. In this work, we ... More
Luminosity distance in Swiss cheese cosmology with randomized voids. II. Magnification probability distributionsSep 09 2011Nov 14 2011We study the fluctuations in luminosity distances due to gravitational lensing by large scale (> 35 Mpc) structures, specifically voids and sheets. We use a simplified "Swiss cheese" model consisting of a \Lambda -CDM Friedman-Robertson-Walker background ... More
Foundations of the self-force problem in arbitrary dimensionsApr 10 2018The self-force problem---which asks how self-interaction affects a body's motion---has been poorly studied for spacetime dimensions $d \neq 4$. We remedy this for all $d \geq 3$ by nonperturbatively constructing momenta such that forces and torques acting ... More
Coherent frequency conversion in a superconducting artificial atom with two internal degrees of freedomJan 19 2012By adding a large inductance in a dc-SQUID phase qubit loop, one decouples the junctions' dynamics and creates a superconducting artificial atom with two internal degrees of freedom. In addition to the usual symmetric plasma mode ({\it s}-mode) which ... More
High-resolution radio imaging of the gamma-ray blazar candidate J1331+2932Feb 20 2019Active galactic nuclei are the most luminous persistent (non-transient, even if often variable) objects in the Universe. They are bright in the entire electromagnetic spectrum. Blazars are a special class where the jets point nearly to our line of sight. ... More
Unexpectedly allowed transition in two inductively coupled transmonsJan 20 2016We present experimental results in which the unexpected zero-two transition of a circuit composed of two inductively coupled transmons is observed. This transition shows an unusual magnetic flux dependence with a clear disappearance at zero magnetic flux. ... More
Kerr coefficients of plasma resonances in Josephson junction chainsMay 21 2015Aug 24 2015We present an experimental and theoretical analysis of the self- and cross-Kerr effect of extended plasma resonances in Josephson junction chains. We calculate the Kerr coefficients by deriving and diagonalizing the Hamiltonian of a linear circuit model ... More
Prescriptions for measuring and transporting local angular momenta in general relativityFeb 04 2016For observers in curved spacetimes, elements of the dual space of the set of linearized Poincar\'e transformations from an observer's tangent space to itself can be naturally interpreted as local linear and angular momenta. We present an operational procedure ... More
The most distant radio quasars at the highest resolutionMay 12 2011There are about 50 quasars known at redshifts z>5.7 to date. Only three of them are detected in the radio (J0836+0054, z=5.77; J1427+3312, z=6.12; J1429+5447, z=6.21). The highest-redshift quasars are in the forefront of current astrophysical and cosmological ... More
Quantum signature of analog Hawking radiation in momentum spaceJun 19 2014Jul 07 2015We consider a sonic analog of a black hole realized in the one-dimensional flow of a Bose-Einstein condensate. Our theoretical analysis demonstrates that one- and two-body momentum distributions accessible by present-day experimental techniques provide ... More
High-Resolution Radio Image of a Candidate Radio Galaxy at z=5.72Oct 29 2018Recently, Saxena et al. (2018) reported the discovery of a possible radio galaxy, J1530$+$1049 at a redshift of z=5.72. We observed the source with the European Very Long Baseline Interferometry Network at $1.7$ GHz. We detected two faint radio features ... More
On short sums of trace functionsAug 03 2015Jun 23 2016We consider sums of oscillating functions on intervals in cyclic groups of size close to the square root of the size of the group. We first prove non-trivial estimates for intervals of length slightly larger than this square root (bridging the "Poly\'a-Vinogradov ... More
Nontrivial photon statistics in small scale lasersOct 05 2017Photon statistical measurements on a semiconductor microlaser, obtained using single-photon counting techniques, show that a newly discovered pulsed emission regime is inconsistent with all current theoretical modeling. The observed spike dynamics, typical ... More
Into the central 10 pc of the most distant known radio quasar. VLBI imaging observations of J1429+5447 at z=6.21Jun 03 2011Context: There are about 60 quasars known at redshifts z>5.7 to date. Only three of them are detected in the radio above 1 mJy flux density at 1.4 GHz frequency. Among them, J1429+5447 (z=6.21) is the highest-redshift radio quasar known at present. These ... More
Flaring radio lanterns along the ridge line: long-term oscillatory motion in the jet of S5 1803+784Apr 25 2018We present a detailed analysis of 30 very long baseline interferometric observations of the BL Lac object S5 1803+784 (z=0.679), obtained between mean observational time 1994.67 and 2012.91 at observational frequency 15 GHz. The long-term behaviour of ... More
Phase segregation on the nanoscale in Na2C60Jul 10 2006Oct 15 2006Na2C60 is believed to be an electron-hole counterpart of the Mott-Jahn--Teller insulator A4C60 salts. We present a study of infrared, ESR, NMR spectroscopy, X-ray diffraction, chemical composition and neutron scattering on this compound. Our spectroscopic ... More
Comprehensive analysis of HD 105, a young Solar System analogNov 15 2018HD~105 is a nearby, pre-main sequence G0 star hosting a moderately bright debris disc ($L_{\rm dust}/L_{\star} \sim 2.6\times10^{-4}$). HD~105 and its surroundings might therefore be considered an analogue of the young Solar System. We refine the stellar ... More
Epitaxial rhenium microwave resonatorsMay 09 2016We have fabricated rhenium microwave resonators from epitaxial films. We have used thin films of different structural quality depending on their growth conditions. The resonators were coupled to a microwave transmission line which allows the measurement ... More
Nonlinear waves of polarization in two-component Bose-Einstein condensatesAug 04 2013Waves with different symmetries exist in two-component Bose-Einstein condensates (BECs) whose dynamics is described by a system of coupled Gross-Pitaevskii (GP) equations. A first type of waves corresponds to excitations for which the motion of both components ... More
A spinning supermassive black hole binary model consistent with VLBI observations of the S5 1928+738 jetFeb 11 2014Sep 04 2014Very Long Baseline Interferometry (VLBI) allows for high-resolution and high-sensitivity observations of relativistic jets, that can reveal periodicities of several years in their structure. We perform an analysis of long-term VLBI data of the quasar ... More
Dominating Scale-Free Networks Using Generalized Probabilistic MethodsJun 18 2014We study ensemble-based graph-theoretical methods aiming to approximate the size of the minimum dominating set (MDS) in scale-free networks. We analyze both analytical upper bounds of dominating sets and numerical realizations for applications. We propose ... More
Persistent gravitational wave observables: general frameworkDec 31 2018Apr 30 2019The gravitational wave memory effect is characterized by the permanent relative displacement of a pair of initially comoving test particles that is caused by the passage of a burst of gravitational waves. Recent research on this effect has clarified the ... More
Activity driven fluctuations in living cellsMay 24 2015We propose a model for the dynamics of a probe embedded in a living cell, where both thermal fluctuations and nonequilibrium activity coexist. The model is based on a confining harmonic potential describing the elastic cytoskeletal matrix, which undergoes ... More
Modeling the dynamics of a tracer particle in an elastic active gelJul 03 2015The internal dynamics of active gels, both in artificial (in-vitro) model systems and inside the cytoskeleton of living cells, has been extensively studied by experiments of recent years. These dynamics are probed using tracer particles embedded in the ... More
Constraining the parameters of the putative supermassive binary black hole in PG 1302-102 from its radio structureJun 23 2015Sep 08 2015We investigate the pc-scale kinematics and kpc-scale radio morphology of the quasar PG 1302-102, which may harbour a sub-pc separation supermassive binary black hole system at its centre as inferred from optical variability. High-resolution radio interferometric ... More
Thermodynamics at the microscale: from effective heating to the Brownian Carnot engineMay 16 2016We review a series of experimental studies of the thermodynamics of nonequilibrium processes at the microscale. In particular, in these experiments we studied the fluctuations of the thermodynamic properties of a single optically-trapped microparticle ... More
On stochastic gradient Langevin dynamics with dependent data streams in the logconcave caseDec 06 2018Stochastic Gradient Langevin Dynamics (SGLD) is a combination of a Robbins-Monro type algorithm with Langevin dynamics in order to perform data-driven stochastic optimization. In this paper, the SGLD method with fixed step size $\lambda$ is considered ... More
Modeling the RV jitter of early M dwarfs using tomographic imagingJun 06 2016In this paper we show how tomographic imaging (Zeeman Doppler Imaging, ZDI) can be used to characterize stellar activity and magnetic field topologies, ultimately allowing to filter out the radial velocity (RV) activity jitter of M-dwarf moderate rotators. ... More
Persistent gravitational wave observables: general frameworkDec 31 2018Jan 23 2019The gravitational wave memory effect is characterized by the permanent relative displacement of a pair of initially comoving test particles that is caused by the passage of a burst of gravitational waves. Recent research on this effect has clarified the ... More
A single radio-emitting nucleus in the dual AGN candidate NGC 5515Jun 19 2014The Seyfert galaxy NGC 5515 has double-peaked narrow-line emission in its optical spectrum, and it has been suggested that this could indicate that it has two active nuclei. We observed the source with high resolution Very Long Baseline Interferometry ... More
On stochastic gradient Langevin dynamics with dependent data streams in the logconcave caseDec 06 2018Mar 25 2019Stochastic Gradient Langevin Dynamics (SGLD) is a combination of a Robbins-Monro type algorithm with Langevin dynamics. In this paper, the SGLD method with fixed step size $\lambda$ is considered in order to sample from a logconcave target distribution ... More
From motor-induced fluctuations to mesoscopic dynamics in epithelial tissuesDec 04 2015Molecular motors power spatial fluctuations in epithelial tissues. We evaluate these fluctuations in MDCK monolayers by tracking tricellular junctions, leading us to highlight the non-Gaussian statistics of the junction displacement. Using a mesoscopic ... More
Vibrational spectra of C60C8H8 and C70C8H8 in the rotor-stator and polymer phasesJun 30 2007Sep 19 2007C60-C8H8 and C70-C8H8 are prototypes of rotor-stator cocrystals. We present infrared and Raman spectra of these materials and show how the rotor-stator nature is reflected in their vibrational properties. We measured the vibrational spectra of the polymer ... More
Post-1-Newtonian equations of motion for systems of arbitrarily structured bodiesApr 26 2004Oct 04 2013We give a surface integral derivation of post-1-Newtonian translational equations of motion for a system of arbitrarily structured bodies, including the coupling to all the bodies' mass and current multipole moments. The derivation requires only that ... More
Nanoscale characterization of thin immersion silver coatings on copper substratesFeb 05 2015Microelectronic-grade copper foils were immersion silver plated in a home-made non-cyanide alkaline silver nitrate - thiosulfate solution and in two commercially available industrial baths via contact reductive precipitation. The concentration depth profiles ... More
Archival Legacy Investigations of Circumstellar Environments (ALICE): Statistical assessment of point source detectionsSep 25 2015The ALICE program, for Archival Legacy Investigation of Circumstellar Environment, is currently conducting a virtual survey of about 400 stars, by re-analyzing the HST-NICMOS coronagraphic archive with advanced post-processing techniques. We present here ... More
Real-Time Discrete SPAD Array Readout Architecture for Time of Flight PETJun 15 2014Single photon avalanche diode (SPAD) arrays have proven themselves as serious candidates for time of flight positron emission tomography (PET). Discrete readout schemes mitigate the low-noise requirements of analog schemes and offer very fine control ... More
Four dual AGN candidates observed with the VLBAMay 30 2016According to hierarchical structure formation models, merging galaxies are expected to be seen in different stages of their coalescence. However, currently there are no straightforward observational methods neither to select nor to confirm a large number ... More
An efficient phase-shifting scheme for bolometric additive interferometryJun 02 2008Context: Most upcoming CMB polarization experiments will use direct imaging to search for the primordial gravitational waves through the B-modes. Bolometric interferometry is an appealing alternative to direct imaging that combines the advantages of interferometry ... More
Ground Tests of Einstein's Equivalence Principle: From Lab-based to 10-m Atomic FountainsJul 21 2015To date, no framework combining quantum field theory and general relativity and hence unifying all four fundamental interactions, exists. Violations of the Einstein's equivalence principle (EEP), being the foundation of general relativity, may hold the ... More
On the nature of bright compact radio sources at z>4.5Sep 02 2016High-redshift radio-loud quasars are used to, among other things, test the predictions of cosmological models, set constraints on black hole growth in the early universe and understand galaxy evolution. Prior to this paper, 20 extragalactic radio sources ... More
Effects of the turbulent ISM on radio observations of quasarsDec 15 2006In radio bands, the study of compact radio sources can be affected by propagation effects through the Interstellar Medium. These are usually attributed to the presence of turbulent intervening plasma along the line of sight. Here, two of such effects ... More
VLBI observations of four radio quasars at $z>4$: blazars or not?Jan 17 2017Blazars are active galactic nuclei (AGN) whose relativistic jets point nearly to the line of sight. Their compact radio structure can be imaged with very long baseline interferometry (VLBI) on parsec scales. Blazars at extremely high redshifts provide ... More
Electronic conductivity and structural distortion at the interface between insulators SrTiO3 and LaAlO3Nov 04 2005Mar 13 2006When insulator LaAlO3 is grown by epitaxy onto a TiO2-terminated {100} surface of insulator SrTiO3, the resulting system has a metallic character. This phenomenon has been associated with an electrostatic frustration at the interface, as {100} surfaces ... More
HD 65949: Rosetta Stone or Red HerringFeb 15 2010HD 65949 is a late B star with exceptionally strong Hg II at 3984[A], but it is not a typical HgMn star. The Re II spectrum is of extraordinary strength. Abundances, or upper limits are derived here for 58 elements based on a model with Teff = 13100K, ... More
Sound propagation in a uniform superfluid two-dimensional Bose gasApr 11 2018In superfluid systems several sound modes can be excited, as for example first and second sound in liquid helium. Here, we excite propagating and standing waves in a uniform two-dimensional Bose gas and we characterize the propagation of sound in both ... More
A seasonal cycle and an abrupt change in the variability characteristics of the intraday variable source S4 0954+65Apr 23 2012Jul 03 2012The BLLac object S4 0954+65 is one of the main targets of the Urumqi monitoring program targeting IntraDay Variable (IDV) sources. Between August 2005 and December 2009, the source was included in 41 observing sessions, carried out at a frequency of 4.8 ... More
The loud and the quiet: searching for radio counterparts of two radio-weak BL Lac candidates with VLBIOct 02 2018BL Lac objects are known to have compact jets inclined to our line of sight at a small angle, showing prominent radio emission. Two radio-weak BL Lac candidates with no counterparts in current radio surveys were recently reported by Massaro et al. (2017). ... More
Three little radio galaxies in the early UniverseFeb 19 2019Volonteri et al. (2011) found that the number of radio-loud quasars above redshift 4 calculated from the luminosity function (based upon Swift/BAT observations) is much smaller than the number estimated from the known high-redshift beamed sources, blazars, ... More
Wave-front error breakdown in LGS MOAO validated on-sky by CANARYOct 15 2016CANARY is the multi-object adaptive optics (MOAO) on-sky pathfinder developed in the perspective of Multi-Object Spectrograph on Extremely Large Telescopes~(ELTs). In 2013, CANARY was operated on-sky at the William Herschel telescope~(WHT), using three ... More
Electronic and Magnetic Properties of the Candidate Magnetocaloric-Material Double Perovskites La$_2$MnCoO$_6$, La$_2$MnNiO$_6$ and La$_2$MnFeO$_6$Sep 20 2018The search for room-temperature magnetocaloric materials for refrigeration has led to investigations of double perovskites. In particular, a puzzle has appeared in the La$_2$MnNiO$_6$, La$_2$MnCoO$_6$ and La$_2$MnFeO$_6$ family of compounds. They share ... More
HD 164492C: a rapidly-rotating, H$α$-bright, magnetic early B star associated with a 12.5d spectroscopic binaryOct 08 2016We employ high resolution spectroscopy and spectropolarimetry to derive the physical properties and magnetic characteristics of the multiple system HD 164492C, located in the young open cluster M20. The spectrum reveals evidence of 3 components: a broad-lined ... More
FIRST, a fibered aperture masking instrument II. Spectroscopy of the Capella binary system at the diffraction limitOct 29 2013FIRST is a prototype instrument built to demonstrate the capabilities of the pupil remapping technique, using single-mode fibers and working at visible wavelengths. We report on observations of the binary system Capella at three epochs over a period of ... More