Quantum illumination uses entangled signal-idler photon pairs to boost the detection efficiency of low-reflectivity objects in environments with bright thermal noise. Its advantage is particularly ...evident at low signal powers, a promising feature for applications such as noninvasive biomedical scanning or low-power short-range radar. Here, we experimentally investigate the concept of quantum illumination at microwave frequencies. We generate entangled fields to illuminate a room-temperature object at a distance of 1 m in a free-space detection setup. We implement a digital phase-conjugate receiver based on linear quadrature measurements that outperforms a symmetric classical noise radar in the same conditions, despite the entanglement-breaking signal path. Starting from experimental data, we also simulate the case of perfect idler photon number detection, which results in a quantum advantage compared with the relative classical benchmark. Our results highlight the opportunities and challenges in the way toward a first room-temperature application of microwave quantum circuits.
We investigate a general scheme for generating, either dynamically or in the steady state, continuous variable entanglement between two mechanical resonators with different frequencies. We employ an ...optomechanical system in which a single optical cavity mode driven by a suitably chosen two-tone field is coupled to the two resonators. Significantly large mechanical entanglement can be achieved, which is extremely robust with respect to temperature.
We propose and analyse a feasible experimental scheme for a quantum force sensor based on the elimination of backaction noise through coherent quantum noise cancellation (CQNC) in a hybrid ...atom-cavity optomechanical setup assisted with squeezed vacuum injection. The force detector, which allows for a continuous, broadband detection of weak forces well below the standard quantum limit (SQL), is formed by a single optical cavity simultaneously coupled to a mechanical oscillator and to an ensemble of ultracold atoms. The latter acts as a negative-mass oscillator so that atomic noise exactly cancels the backaction noise from the mechanical oscillator due to destructive quantum interference. Squeezed vacuum injection enforces this cancellation and allows sub-SQL sensitivity to be reached in a very wide frequency band, and at much lower input laser powers.
L’exposition archéologique tenue à Gênes d’octobre 2004 à janvier 2005, consacrée aux Ligures, a été accompagnée d’un important volume-catalogue. Les six cents pages font le point des connaissances ...actuelles concernant ce peuple qui occupait un territoire allant de la Provence à l’Arno et de la côte ligure aux Alpes occidentales, jusqu’au Pô. La période concernée se situe entre les guerres ligures et les débuts de la romanisation (II–Ier siècle) depuis le Bronze Moyen (XVIe siècle). Durant cette dernière période, les protohistoriens reconnaissent en Italie nord-occidentale, au sud du Pô, plusieurs éléments culturels ayant de nombreuses affinités avec les civilisations contemporaines du Midi de la France plus qu’avec le reste de l’Italie septentrionale. L’exposition d’objets archéologiques choisis dans une soixantaine de musées, la relecture des sources historiographiques gréco-latines, la présentation des nouvelles découvertes provenant du travail des Surintendances Archéologiques de la Ligurie, de la Toscane, de l’Emilie-Romagne et du Piémont, font de ce catalogue
une somme scientifique qui manquait encore à la littérature archéologique. Cet ouvrage apporte de nombreux éléments inédits propices àla discussion sur l’une des plus importantes populations de la Méditerranée occidentale. Les Ligures qui, dans la géographie de l’oikoumène connue par les Grecs des VIe et IVe siècles, étaient le synonyme d’Ouest après le Sud et l’Orient des Ethiopiens et avant le Nord des Celtes et des Scythes.
•A low-power benchtop TXRF system was used for analysis of 70 wine samples.•The metal content of K, Ca, Fe, Cu, Zn, Mn, Sr, Rb, Ba, Pb, Ni, Cr and V was estimated by chemometric methods.•Mn, K, Ni, ...Sr, Rb and Ba were the main variables used to differentiate by wine type and origin.•LDA showed good detection and prediction abilities with selected elements.•Classification of origin and type of Croatian wines by chemometric tools.
The contents of selected metals (K, Ca, Fe, Cu, Zn, Mn, Sr, Rb, Ba, Pb, Ni, Cr and V) in 70 wine samples from Continental and Adriatic part of Croatia and different types of wine (red and white) were determined by TXRF. The aim of this study was to compare the elemental composition of wines from two different regions and to determine the discriminant ability of each variable and to indicate which variables discriminate between the four categories considered.
Principal component analysis and cluster analysis showed that K, Mn, Ba and Ni can be considered as the most important characteristics to distinguish between Continental red and white wines, Rb, Ni and Ba for Continental red and Adriatic red wines while Sr is the only metal that completely distinguishes the samples of each category. Finally, linear discriminant analysis showed good recognition (100%) and prediction abilities (96.43%) using these selected elements.
We present an experimental study of dynamical back-action cooling of the fundamental vibrational mode of a thin semitransparent membrane placed within a high-finesse optical cavity. We study how the ...radiation-pressure interaction modifies the mechanical response of the vibrational mode, and the experimental results are in agreement with a Langevin equation description of the coupled dynamics. The experiments are carried out in the resolved sideband regime, and we have observed cooling by a factor of 350. We have also observed the mechanical frequency shift associated with the quadratic term in the expansion of the cavity mode frequency versus the effective membrane position, which is typically negligible in other cavity optomechanical devices.
PDF
