We present a calculation of a neutrino decay scenario in the early Universe. The specific decay is ν_{2} \to ν_{1} + ϕ, where ϕis a boson. If there is a neutrino mass hierarchy, m_{ν_{e}} m_{ν_μ} m_{ν_τ}, we show that it is possible to generate stimulated decay and effects similar to atomic lasing without invoking new neutrinos, even starting from identical neutrino distributions. Under the right circumstances the decay can be to very low momentum boson states thereby producing something similar to a Bose condensate, with possible consequences for structure formation. Finally, we argue that this type of decay may also be important other places in early Universe physics.
Category: particle physics – Page 549
The Sun Is Spitting Out Strange Patterns of Gamma Rays—and No One Knows Why
Scientists have studied this ebb and flow for centuries, but only began understanding its effects on our planet at the dawn of the space age in the mid-20th century. Now it is clear that around solar maximum the sun is more likely to bombard Earth with charged particles that damage satellites and power grids. The solar cycle also plays a minor role in climate, as variations in irradiance can cause slight changes in average sea-surface temperatures and precipitation patterns. Thus, a better understanding of the cycle’s physical drivers is important for sustainable living on Earth.
Yet scientists still lack a model that perfectly predicts the cycle’s key details, such as the exact duration and strength of each phase. “I think the solar cycle is so stable and clear that there is something fundamental that we are missing,” says Ofer Cohen, a solar physicist at the University of Massachusetts Lowell. One obstacle to figuring it out, he says, is that crucial details of the apparent mechanisms behind the cycle—such as the sun’s magnetic field—are largely hidden from our view. But that might be about to change.
Tim Linden, an astronomer at The Ohio State University, and his colleagues recently mapped how the sun’s high-energy glow dances across its face over time. They found a potential link between these high-energy emissions, the sun’s fluctuating magnetic field and the timing of the solar cycle. This, many experts argue, could open a new window into the inner workings of our nearest, most familiar star.
Research sheds light on how silver ions kill bacteria
The antimicrobial properties of silver have been known for centuries. While it is still a mystery as to exactly how silver kills bacteria, University of Arkansas researchers have taken a step toward better understanding the process by looking at dynamics of proteins in live bacteria at the molecular level.
Traditionally, the antimicrobial effects of silver have been measured through bioassays, which compare the effect of a substance on a test organism against a standard, untreated preparation. While these methods are effective, they typically produce only snapshots in time, said Yong Wang, assistant professor of physics and an author of the study, published in the journal Applied and Environmental Microbiology.
Instead, Wang and his colleagues used an advanced imaging technique, called “single-particle-tracking photoactivated localization microscopy,” to watch and track a particular protein found in E. coli bacteria over time.
Quantum Computing With Particles Of Light: A $215 Million Gamble
PsiQuantum is a little-known quantum computing startup, however it recently had no trouble raising almost a quarter of a billion dollars from Microsoft’s M12 venture fund and other investors. That is in addition to a whopping $230 million it received last year from a fund formed by Andy Rubin, developer of the Android operating system.
The company was founded in 2016 by British professor Jeremy O’Brien and three other academics, Terry Rudolph, Mark Thompson, and Pete Shadbolt. In just a few years, they have quietly grown the company from a few employees to a robust technical staff of more than 100.
Compared to today’s modest quantum computing capabilities, PsiQuantum’s elevator pitch for investors sounds like a line from a science fiction movie. O’Brien not only says he is going to build a fault-tolerant quantum computer with a staggering one million qubits, he also says he is going to do it within five years. O’Brien’s technology of choice for this claim is silicon photonics, which uses particles of light called photons to perform quantum calculations. Theoretically, photons behave as both waves and particles, but that’s a subject for another article. Quantum computing technologies in use today are primarily superconductors and trapped ion. However, there is plenty of research that shows photonics holds a lot of promise.
Neutrinos could shed light on why the Universe has so much more matter than antimatter
A major finding in particle physics reminds us of the importance of robust preliminary results — and paves the way for more exciting discoveries.
A quantum metasurface that can simultaneously control multiple properties of light
:oooo.
Metasurfaces are artificial materials designed at the nanoscale, which can control the scattering of light with exceptionally high precision. Over the past decade or so, these materials have been used to create a variety of technological tools ranging from sensors to lenses and imaging techniques.
A research team led by Mikhail Lukin at Harvard University has recently proposed a new type of metasurface that can control both the spatiotemporal and quantum properties of transmitted and reflected light. In a paper published in Nature Physics, the team showed that realizing a quantum metasurface is possible and could be achieved by entangling the macroscopic response of thin atom arrays to light.
“Quantum metasurfaces are an entirely new type of materials designed atom by atom, which enable applications such as quantum computation with photons,” Rivka Bekenstein, the lead author of the recent paper, told Phys.org. “We combined a state-of-the-art technique for manipulating the state of many atoms by long-range interactions (i.e., Rydberg interactions) with a recent discovery of how a single sheet of atoms can reflect light. We identified an architecture that can be realized in the laboratory, in which a single layer of atoms can act as a switchable quantum mirror.”
Researchers solve puzzle of Compton scattering: New approach for testing theories in quantum mechanics
When the American physicist Arthur Compton discovered that light waves behave like particles in 1922, and could knock electrons out of atoms during an impact experiment, it was a milestone for quantum mechanics. Five years later, Compton received the Nobel Prize for this discovery. Compton used very shortwave light with high energy for his experiment, which enabled him to neglect the binding energy of the electron to the atomic nucleus. Compton simply assumed for his calculations that the electron rested freely in space.
During the following 90 years up to the present, numerous experiments and calculations have been carried out with regard to Compton scattering that continually revealed asymmetries and posed riddles. For example, it was observed that in certain experiments, energy seemed to be lost when the motion energy of the electrons and light particles (photons) after the collision were compared with the energy of the photons before the collision. Since energy cannot simply disappear, it was assumed that in these cases, contrary to Compton’s simplified assumption, the influence of the nucleus on the photon-electron collision could not be neglected.
For the first time in an impact experiment with photons, a team of physicists led by Professor Reinhard Dörner and doctoral candidate Max Kircher at Goethe University Frankfurt has now simultaneously observed the ejected electrons and the motion of the nucleus. To do so, they irradiated helium atoms with X-rays from the X-ray source PETRA III at the Hamburg accelerator facility DESY. They detected the ejected electrons and the charged rest of the atom (ions) in a COLTRIMS reaction microscope, an apparatus that Dörner helped develop and which is able to make ultrafast reactive processes in atoms and molecules visible.
Physicists to improve plasma fusion mirror devices with $5 million grant
Fusion research began in earnest in the 1960s, when scientists developed mirror machines. These linear tubes have pinched magnetic field lines on either end that act like mirrors, reflecting the charged plasma particles inward and retaining them and their heat in the machine. American researchers halted mirror research three decades ago, mainly due to an inability to contain the plasma.
WHAM will essentially take the team’s research back to the mirror machine days, but with significant upgrades.
“We hope to go well beyond what was done in the mirror program because we have access to very-high-field superconducting magnets like those being built by our partners for toroidal (donut-shaped) plasmas,” Forest says. “These magnets and heating systems simply weren’t available 20 years ago. It’s a new look at an older concept using new technology.”