Teleporting Toward a Quantum Internet NGC 3718, NGC 3729 and other galaxies have been analyzed using machine learning algorithms that can be “taught” to recognize astrophysical similarities. The same technology is now being applied to cancer images, as well. Credits: Catalina Sky Survey, U of Arizona, and Catalina Realtime Transient Survey, Caltech. A lung specimen that was analyzed using the same machine learning algorithms that were originally developed for space research. Credits: Early Research Detection Network/University of Colorado JPL and National Cancer Institute Renew Big Data Partnership Every day, NASA spacecraft beam down hundreds of petabytes of data, all of which has to be codified, stored and distributed to scientists across the globe. For the past 15 years, the big data techniques pioneered by NASA’s Jet Propulsion Laboratory in Pasadena, California, have been revolutionizing biomedical research. Crichton said JPL has led the way when it comes to taking data from raw observations to scientific conclusions.
Record : une intrication de 219 ions pour l'ordinateur quantique ! Les ions de béryllium, rendus visibles par fluorescence sur cette image (il est possible d'en distinguer 91 à gauche et 124 à droite), forment un réseau cristallin de maille triangulaire. Ils constituent un simulateur quantique et ouvrent une nouvelle voie pour obtenir peut-être un jour au moins un calculateur quantique. © NIST Record : une intrication de 219 ions pour l'ordinateur quantique ! - 1 Photo Quand il explorait le concept d’ordinateur quantique au début des années 1980, Richard Feynman pensait à une machine de Turing universelle, capable d'exécuter n’importe quel algorithme, mais aussi à un simulateur quantique. Par exemple, le comportement des électrons dans les supraconducteurs exotiques à hautes températures critiques est mal compris. Deux problèmes à résoudre pour réaliser un ordinateur quantique Pour être performantes, ces machines imposent un grand nombre de qubits, les équivalents quantiques des bits d’informations des ordinateurs classiques. À voir aussi sur Internet
Computer solves a major time travel problem It is more than 120 years since H.G. Wells published The Time Machine, the novel that was to popularise the concept of time travel and lead to myriad stories on the theme. But it is only now that we have finally developed a plotline for time travel that makes logical sense – and it has been penned by a machine. The breakthrough involves the grandfather paradox – that favourite plaything of philosophers where somebody travels into the past and kills their own grandfather, preventing the existence of one of their parents, and therefore their own. But the problem is, if the protagonist doesn’t exist, then how could they go back in time to set off the chain of events in the first place? The paradox is often extended, in various guises, to regard any action that alters the past – such as Marty McFly avoiding the amorous attention of his mother, Lorraine, and ensuring she marries his father, George, in Back to the Future. Resolving the paradox with just one universe has proved trickier.
Introduction aux algorithmes d’apprentissage profonds — Notes de cours IFT6266 Hiver 2012 Pour une revue récente de l’apprentissage profond, voir: Yoshua Bengio, Learning Deep Architectures for AI, Foundations and Trends in Machine Learning, 2(1), 2009 Profondeur Les calculs effectués pour produire une sortie à partir d’entrées peuvent être représentés par un graphe de flot: un graphe de flot est un graphe qui représente un calcul, dans lequel chaque nœud représente une opération élémentaire et une valeur (le résultat de cette opération sur les enfants de ce nœud). Les nœuds d’entrée n’ont pas d’enfants, et les nœuds de sortie n’ont pas de parents. Le graphe de flot de l’expression peut être représenté par un graphe avec: deux noeuds d’entrée, et ;un nœud pour la division, , dont les entrées (les enfants) sont et ;un nœud pour le carré, prenant seulement comme entrée;un nœud pour l’addition, dont la valeur serait , prenant comme entrées les nœuds et ;un nœud de sortie calculant le sinus, dont la seule entrée est le nœud d’addition. Manque de profondeur nœuds (pour .
Scientists visualise quantum behaviour of hot electrons for first time Scientists have, for the first time, identified a method of visualising the quantum behaviour of electrons on a surface. The findings present a promising step forward towards being able to manipulate and control the behaviour of high energy, or 'hot', electrons. A Scanning Tunnelling Microscope was used to inject electrons into a silicon surface, decorated with toluene molecules. By measuring the precise atomic positions from which molecules departed on injection, the team were able to identify that electrons were governed by quantum mechanics close to the tip, and then by more classical behaviour further away. The team found that the molecular lift-off was "suppressed" near the point of charge injection, because the classical behaviour was inhibited. The research, published in Nature Communications, is the result of ongoing collaboration between the University of Birmingham and the University of Bath. "These findings are, crucially, undertaken at room temperature. More information: K.
Ghost particles may explain why gravity is so surprisingly weak ESO/T.Preibisch Ghostly particles could be haunting our universe. A new theory claims that the cosmos is full of unseen particle families that don’t interact with each other. If true, the model could explain why gravity is so puzzlingly weak. The idea is an alternative to supersymmetry, a theory in which every known particle has a heavier partner. Maybe that’s because we need not just one set of partner particles, but many, says Nima Arkani-Hamed at Princeton University. “The idea is a little wild,” admits Tim Cohen at the University of Oregon in Eugene, who teamed up with Arkani-Hamed and others to work on the new theory. Advertisement The group began by tweaking the story of what happened in the big bang. Then, because particles always want to decay into something less energetic, the reheatons broke down into smaller particles – the ones that structure the universe today. Next, the physicists took our familiar standard model of particles, and introduced many copies of it into the story.
Les nouveaux éléments chimiques ont un nom ! Nihonium, Moscovium, Tennessine, Oganesson... Le 30 décembre 2015, l’IUPAC (Union internationale de chimie pure et appliquée) avait validé l’intégration dans le tableau de Mendeleïev de quatre noyaux dits transuraniens (plus lourd que l’uranium 92), les éléments 113, 115, 117, 118. Si compléter la septième période du tableau des éléments a pris plus de 10 ans, leur attribuer un nom définitif n’a pris que quelques mois. Désormais, depuis le 8 juin 2016, selon les souhaits des laboratoires découvreurs, l’élément 113 (Nh) est le Nihonium.
Bibliothèque scientifique: Livre : Qu’est-ce que la mécanique quantique? de Thomas Boyer-Kassem PDF Livre : Qu’est-ce que la mécanique quantique? de Thomas Boyer-Kassem PDF La mécanique quantique est une théorie physique contemporaine réputée pour ses défis au sens commun et ses paradoxes. Supercomputer comes up with a profile of dark matter: Standard Model extension predicts properties of candidate particle In the search for the mysterious dark matter, physicists have used elaborate computer calculations to come up with an outline of the particles of this unknown form of matter. To do this, the scientists extended the successful Standard Model of particle physics which allowed them, among other things, to predict the mass of so-called axions, promising candidates for dark matter. The German-Hungarian team of researchers led by Professor Zoltán Fodor of the University of Wuppertal, Eötvös University in Budapest and Forschungszentrum Jülich carried out its calculations on Jülich's supercomputer JUQUEEN (BlueGene/Q) and presents its results in the journal Nature. "Dark matter is an invisible form of matter which until now has only revealed itself through its gravitational effects. What it consists of remains a complete mystery," explains co-author Dr Andreas Ringwald, who is based at DESY and who proposed the current research. Explore further: 3 knowns and 3 unknowns about dark matter
Room-temp superconductors could be possible Superconductors are the holy grail of energy efficiency. These mind-boggling materials allow electric current to flow freely without resistance. But that generally only happens at temperatures within a few degrees of absolute zero (minus 459 degrees Fahrenheit), making them difficult to deploy today. However, if we're able to harness the powers of superconductivity at room temperature, we could transform how energy is produced, stored, distributed and used around the globe. In a recent breakthrough, scientists at the Department of Energy's Brookhaven National Laboratory got one step closer to understanding how to make that possible. Under the right conditions—which, right now, include ultra-chilly temperatures—electrical current flows freely through these cuprate superconductors without encountering any "roadblocks" along the way. Creating the right conditions for superconductivity in cuprates also involves adding other chemical elements such as strontium.
Relaxons Heat Up Thermal Transport Alan McGaughey, Department of Mechanical Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213, USA A recasting of the theory that underlies thermal transport in electrical insulators relies on new vibrational modes called relaxons. Thermal transport—the flow of energy in the form of heat—is ubiquitous in engineered and natural systems. Managing it efficiently is critical for increasing the performance and lifetime of electronic circuitry, energy-conversion devices, and living organisms. In electrically insulating, or dielectric, crystals, all atoms are at regular positions in a periodic lattice. For decades, phonons have formed the basis of our understanding of thermal transport in dielectric crystals. In their study, Cepellotti and Marzari reformulate the problem of thermal transport in dielectric crystals by proposing new vibrational modes called relaxons in the context of the Boltzmann transport equation. The relaxon picture is attractive. References A.
Des noyaux atomiques en forme de bulle On se représente souvent les noyaux atomiques comme des amas plus ou moins sphériques de protons et de neutrons. En réalité, ils présentent parfois des formes étonnantes : en poire, en cigare, avec un halo... Mais dans toutes ces configurations, le « cœur » est dense. Dès les années 1970, cependant, il a été suggéré que certains noyaux pouvaient avoir un cœur appauvri en protons et former des structures creuses, ou noyaux « bulles ». Ces noyaux bulles se distinguent des autres noyaux connus. La variation de densité du noyau atomique depuis le cœur jusque la surface est principalement dictée par l’interaction forte qui a la particularité d’être répulsive à très courte distance (moins de 0,7 femtomètre), attractive à environ un femtomètre et nulle au-delà de deux femtomètres. Quelques noyaux exotiques découverts par la suite, tels que les noyaux à halos, échappent à cette description. Olivier Sorlin et ses collègues se sont intéressés au silicium 34.
What shape are photons? Quantum holography sheds light Imagine a shaft of yellow sunlight beaming through a window. Quantum physics tells us that beam is made of zillions of tiny packets of light, called photons, streaming through the air. But what does an individual photon “look” like? Does it have a shape? Now, Polish physicists have created the first ever hologram of a single light particle. The result could also be important for technologies that require an understanding of the shape of single photons – such as quantum communication and quantum computers. ”We performed a relatively simple experiment to measure and view something incredibly difficult to observe: the shape of wavefronts of a single photon," says Radoslaw Chrapkiewicz, a physicist at the University of Warsaw and lead author of the new paper, published in Nature Photonics. For hundreds of years, physicists have been working to figure out what light is made of. Photons, travelling as waves, can be in step (called having the same phase).