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Accelerators like RHIC and LHC routinely turn energy into matter by accelerating pieces of atoms near the speed of light and smashing them into one another. The 2012 discovery of the Higgs particle at the LHC is a notable example. At the time, the Higgs was the final unobserved particle in the Standard Model, a theory that describes the fundamental forces and building blocks of atoms. Impressive as it is, physicists know the Standard Model explains only about 4% of the matter and energy in the universe. The ions are nuclei of massive elements like gold or lead, and ion...

The dynamics of electrons change ever so slightly on each interaction with a photon. Physicists at ETH Zurich have now measured such interplay in its arguably purest form—by recording the attosecond-scale time delays associated with one-photon transitions in an unbound electron. The photoelectric effect, whereby photons impinging on matter cause the emission of electrons, is one of the quintessential effects of quantum mechanics. Einstein famously explained the key mechanism underlying the phenomenon in 1905, earning him the 1921 Nobel Prize in Physics. He built on a concept introduced five years earlier by Max Planck: Electromagnetic energy is absorbed and emitted...

Quantum mechanicsResearch updateWave–particle duality quantified for the first time 01 Sep 2021 Complementarity A new twist on the double-slit experiment. (Courtesy: Shutterstock/Andrey VP) One of the most counterintuitive concepts in physics – the idea that quantum objects are complementary, behaving like waves in some situations and like particles in others – just got a new and more quantitative foundation. In a twist on the classic double-slit experiment, scientists at Korea’s Institute for Basic Sciences (IBS) used precisely controlled photon sources to measure a photon’s degree of wave-ness and particle-ness. Their results, published in Science Advances, show that the properties of...

In a demonstration of Einstein’s E=mc2, collisions of light yielded electrons and positrons "Collide light with light, and poof, you get matter and antimatter. It sounds like a simple idea, but it turns out to be surprisingly hard to prove. A team of physicists is now claiming the first direct observation of the long-sought Breit-Wheeler process, in which two particles of light, or photons, crash into one another and produce an electron and its antimatter counterpart, a positron. Like a discussion from an introductory philosophy course, the detection’s significance hinges on the definition of the word “real.” Some physicists argue...

Astronomers have observed record-breaking photons that strain classical theories of accelerationA little before sunrise on July 4, A.D. 1054, imperial astronomers of the Song Dynasty in China spotted an unknown star lighting up the eastern sky. “It’s as bright as Venus, with pointed rays in all four directions and a reddish-white color,” they wrote in notes delivered to the emperor. The glow, which remained visible to the naked eye during the day for almost a month, was from an explosion caused by the spectacular death of a star located 6,500 light-years away in the constellation of Taurus. Its relics are...

Have you ever stopped to wonder exactly how much light has been produced by all the stars in the Universe, over all the time that has passed? Well, now you can wonder no more. An international team of astronomers has actually calculated the amount of starlight in the cosmos. And it's teaching us new things about the early years of our Universe. In the time since the Big Bang - roughly 13.7 billion years - our Universe has produced many, many galaxies, and many more stars. Perhaps around two trillion galaxies, containing around a trillion-trillion stars. For decades, scientists have...

In new experiments, however, the physicists coaxed individual photons to cozy up to each other and link, similar to the way individual atoms stick together in molecules. The photon dance happens in a lab at MIT where the physicists run table-top experiments with lasers. Cantu, his colleague Aditya Venkatramani, a Ph.D. candidate in atomic physics at Harvard University, and their collaborators start by creating a cloud of chilled rubidium atoms. Rubidium is an alkali metal so it typically looks like a silver-white solid. But vaporizing rubidium with a laser and keeping it ultracold creates a cloud the researchers contain in...

Rosetta spacecraft has made a very surprising discovery – namely that the molecular breakup mechanism of “water and carbon dioxide molecules spewing from the comet’s surface” into the atmosphere of comet 67P/Churyumov-Gerasimenko is caused by “electrons close to the surface.” The surprising results relating to the emission of the comet coma came from measurements gathered by the probes NASA funded Alice instrument and is causing scientists to completely rethink what we know about the wandering bodies, according to the instruments science team. “The discovery we’re reporting is quite unexpected,” said Alan Stern, principal investigator for the Alice instrument at the...

Photons generally do not interact with each other in free space but instead one passes through the other with no effect to either one. Vienna University of Technology researchers have made a significant and groundbreaking discovery in the field of quantum mechanics. A team of researchers has developed some unique hardware, which enable photons to interact. This hardware is composed of micro-thin fiber made of glass, which in turn attached to a device called a resonator. The photon particle light can enter the resonator, moves in a circular fashion and then returns to the glass fiber. This change in pathways...

Now physicists at the University of Vienna in Austria have "virtually intertwined" or entangled two particles spinning faster than ever in opposite directions. Entanglement occurs when two particles remain connected so that actions performed on one affect the other, despite the distance between them. (Einstein referred to this eerie connection as "spooky action at a distance.") In the new study, Anton Fickler and his colleagues entangled two photons that had a high orbital angular momentum, a property that measures the twisting of a wave of light. In quantum physics, particles such as photons can behave as particles and waves. Such...

What would science fiction be without laser beams? From handheld ray guns to spaceship-mounted turbolasers, the futuristic weapon of choice definitely involves bright, colorful blasts of energy. In the early 21st century, projectiles still remain the standard means of inflicting damage from a distance. Yet continued research into "directed-energy" weapons by the United States military, among others, could someday bring lasers to a battlefield near you. Lasers are already used in guidance, targeting and communication applications, but significant technological obstacles stand in front of turning them into weapons by themselves. For certain niche scenarios, lasers might prove themselves ideal. It...

Enlarge ImageNano vibrator. A tiny device called a zipper cavity can convert laser light into mechanical energy. Credit: Matt Eichenfield and Jasper Chan, Nature Researchers have built a nanoscale device that vibrates when struck by incoming laser light. The contraption, which is sensitive to the energy of a single photon, could speed the development of new optical communications systems. It could also help scientists probe some of the fundamental properties of matter with greater precision. Light beams might not seem capable of performing mechanical work (photons, the carriers of light waves, have no mass), but at the atomic level...

ScienceDaily (Mar. 4, 2009) — In quantum mechanics, a vanguard of physics where science often merges into philosophy, much of our understanding is based on conjecture and probabilities, but a group of researchers in Japan has moved one of the fundamental paradoxes in quantum mechanics into the lab for experimentation and observed some of the 'spooky action at a distance' of quantum mechanics directly, Hardy's Paradox, the axiom that we cannot make inferences about past events that haven't been directly observed while also acknowledging that the very act of observation affects the reality we seek to unearth, poses a conundrum...

Photonic circuit in which optical force is harnessed to drive nanomechanics. New Haven, Conn. — Science fiction writers have long envisioned sailing a spacecraft by the optical force of the sun’s light. But, the forces of sunlight are too weak to fill even the oversized sails that have been tried. Now a team led by researchers at the Yale School of Engineering & Applied Science has shown that the force of light indeed can be harnessed to drive machines — when the process is scaled to nano-proportions. Their work opens the door to a new class of semiconductor devices that...

The speed of light is the speed of light, and that's that. Right? Well, maybe not. Try and figure this out. Astronomers studying radiation coming from a distant galaxy found that the high energy gamma rays arrived a few minutes after the lower-energy photons, even though they were emitted at the same time. If true, this result would overturn Einstein's theory of relativity, which says that all photons should move at the speed of light. Uh oh Einstein. The discovery was made using the new MAGIC (Major Atmospheric Gamma-ray Imaging Cherenkov) telescope, located on a mountain top on the Canary...

LONDON, England (Reuters) -- Beaming people in Star Trek fashion is still in the realms of science fiction but physicists in Denmark have teleported information from light to matter bringing quantum communication and computing closer to reality. Until now scientists have teleported similar objects such as light or single atoms over short distances from one spot to another in a split second. But Professor Eugene Polzik and his team at the Niels Bohr Institute at Copenhagen University in Denmark have made a breakthrough by using both light and matter. "It is one step further because for the first time it...

Abstract: Among a fringe community of paranoids, aluminum helmets serve as the protective measure of choice against invasive radio signals. We investigate the efficacy of three aluminum helmet designs on a sample group of four individuals. Using a $250,000 network analyser, we find that although on average all helmets attenuate invasive radio frequencies in either directions (either emanating from an outside source, or emanating from the cranium of the subject), certain frequencies are in fact greatly amplified. These amplified frequencies coincide with radio bands reserved for government use according to the Federal Communication Commission (FCC). Statistical evidence suggests the use...