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De natura rerum, mais plutôt au niveau subatomique.

What is energy? The reason energy is so hard to define is because it’s an abstract notion.

What is energy?

Physicists Have Uncovered a Weird Problem While Measuring Time. An Ideal Time Time is a tricky thing in physics, especially when it comes to measurement.

Physicists Have Uncovered a Weird Problem While Measuring Time

And clocks may not solve this problem in the way we once thought they did, researchers are now saying. Une nouvelle expérience du "chat" de Schrödinger vise à comprendre les limites du monde quantique. Une équipe de physicien explique avoir trouvé le moyen « d’élever » le chat de Schrödinger (un objet dans une superposition quantique de deux états avec des propriétés opposées) pour produire des versions agrandies qui pourraient révéler un jour les limites du monde quantique.

Une nouvelle expérience du "chat" de Schrödinger vise à comprendre les limites du monde quantique

Vous avez sans doute entendu parler de ce « chat ». Erwin Schrödinger, l’un des piliers de la physique quantique, imaginait en 1935 l’expérience de pensée suivante (une expérience de pensée, c’est se poser la question : que se passerait-il si…) : si l’on enferme son chat dans une boîte close contenant un poison qui tue l’animal dès qu’il détecte la désintégration d’un atome d’un corps radioactif (événement aléatoire, impossible à prédire), que se passerait-il ? De l’extérieur, on ne peut pas savoir ce qui se passe dans la boîte. Quarks et simulation numérique. Plus d’un comptable froncerait les sourcils s’il apprenait que nous avons fait fonctionner en continu un supercalculateur durant plusieurs années pour n’obtenir qu’une dizaine de résultats.

Quarks et simulation numérique

Pourtant, nous n’avons pas perdu notre temps : pour résoudre des problèmes clés de la théorie des particules fondamentales, seul l’ordinateur pouvait venir à bout des tâches que nous lui avions confiées ! Nous nous intéressions particulièrement aux problèmes nés de la chromodynamique quantique, la théorie qui décrit les interactions entre quarks d'une part et l'interaction forte entre hadrons d'autre part. Formulée dans les années 1970, cette théorie de la physique des particules stipule que les quarks s’associent par deux ou trois pour former des hadrons, c’est-à-dire des particules sur lesquelles s’exerce la force nucléaire forte. Mutation in clock gene explains why some night owls stay up late. DuKai/Getty By New Scientist staff and Press Association A gene variant may explain why some people prefer to stay up late and hate early mornings.

Mutation in clock gene explains why some night owls stay up late

The variant is a mutated form of the CRY1 gene, known to play a role in the circadian clock. Physicists Say They've Created a Fluid With 'Negative Mass' Researchers in the US say they've created a fluid with negative mass in the lab... which is exactly as mind-bending as it sounds.

Physicists Say They've Created a Fluid With 'Negative Mass'

What it means is that, unlike pretty much every other known physical object, when you push this fluid, it accelerates backwards instead of moving forwards. Such an oddity could tell scientists about some of the strange behaviour that happens within black holes and neutron stars. But let's take a step back for a second here, because how can something have negative mass? Hypothetically speaking, matter should be able to have negative mass in the same way that an electric charge can be either negative or positive. On paper that works, but it's still debated in the science world whether negative mass objects can really exist without breaking the laws of physics - something that's not helped by the fact that the very concept is hard for us mere humans to wrap our heads around. Roost. Phil McCarthy/Royal Commission for the Exhibition of 1851 By Richard Webb You’re in London to receive the 1851 Royal Commission medal for outstanding influence on science.

roost

What shape are photons? Quantum holography sheds light. Imagine a shaft of yellow sunlight beaming through a window.

What shape are photons? Quantum holography sheds light

Mysteries of time still stump scientists. Why Time FliesAlan BurdickSimon & Schuster, $28 The topic of time is both excruciatingly complicated and slippery.

Mysteries of time still stump scientists

The combination makes it easy to get bogged down. PhysicsGirl.com. 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.

Des noyaux atomiques en forme de bulle

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 ». 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. 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. The first ever photograph of light as both a particle and wave. (Phys.org)—Light behaves both as a particle and as a wave. 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. 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? 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. As the injected charge propagated from the tip, it induced the molecules to react and 'lift off' from the surface. 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.

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. 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. 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. 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. The research, led by physicist Ivan Bozovic, involves a class of compounds called cuprates, which contain layers of copper and oxygen atoms.

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.