In a groundbreaking discovery, physicists from Aalto University have unveiled a new framework that unites gravity with the forces described by the Standard Model of particle physics, potentially bringing us closer to the long-awaited “Theory of Everything.” This discovery doesn’t just reframe gravity—it offers a fresh perspective on how the fundamental forces of nature might work together¹
Researchers, in a recent Physical Review Letters paper, introduce a new mechanism that may finally allow ultralight dark photons to be considered serious candidates for dark matter, with promising implications for detection efforts.
Around 85% of all matter is believed to be dark matter, yet this elusive substance continues to puzzle scientists because it cannot be observed directly.
One of the candidates for dark matter particles is dark photons. These hypothetical particles are similar to regular photons but have mass and interact only weakly with normal matter.
An international team of researchers, including members from the Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU, WPI), has directly observed “highly charged muonic ions,” a completely new class of exotic atomic systems, in a gas-phase experiment for the first time. The study was published online on June 16 in Physical Review Letters.
The observation highlights the capabilities of advanced superconducting transition-edge-sensor (TES) microcalorimeters in revealing previously inaccessible atomic phenomena.
Normal atoms consist of a nucleus and bound electrons and are electrically neutral. However, when many electrons are removed, the atom becomes highly charged. These charged atoms, known as highly charged ions, are valuable tools for research across various fields, including fundamental physics, nuclear fusion, surface science, and astronomy.
As the number of particles in a physical system increases, its properties can change and different phase transitions (i.e., shifts into different phases of matter) can take place. Microscopic systems (i.e., containing only a few particles) and macroscopic ones (i.e., containing many particles) are thus typically very different, even if the types of particles they are made up of are the same.
Mesoscopic systems lie somewhere between microscopic and macroscopic systems, as they are small enough for individual particle fluctuations to impact their dynamics and yet large enough to support collective particle dynamics. Studying these middle-sized physical systems can yield interesting insight into how the fluctuations of individual particles can give rise to the collective particle behavior observed as a system grows.
Researchers at the University of California Berkeley and Columbia University recently introduced a new approach to precisely realize physical systems that are ideal for studying mesoscopic physics and the underpinnings of phase transitions. Their approach, outlined in a paper published in Nature Physics, relies on the use of atom tweezer arrays to control the number of atoms in a system and how they interact with light.
The answer, it turns out, is yes. In a breakthrough experiment, scientists have observed signs of anyons in a one-dimensional ultracold gas for the first time. The research, published in Nature, involved teams from the University of Innsbruck, Université Paris-Saclay, and Université Libre de Bruxelles.
To reveal the presence of anyons, the scientists carefully injected and accelerated a mobile impurity into a tightly controlled gas of bosons at near absolute zero.
Absolute zero is the theoretical lowest temperature on the thermodynamic scale, corresponding to 0.00 K (−273.15 °C or −459.67 °F). At this point, atomic motion ceases entirely, and the substance no longer emits or absorbs thermal energy.
Researchers have demonstrated the slowing and subsequent reacceleration of a muon beam, increasing the potential of muon beams as a research tool.
About every second, the average human has a rare messenger from the edge of space passing through their body. Muons―similar to electrons but with 200 times the mass―are created naturally when cosmic ions strike the upper atmosphere, producing a shower of particles. Muons can also be created artificially, but these muon beams are very sparse compared to more conventional electron, proton, and ion beams. Over the past few decades, researchers have developed a way to make much denser beams [1, 2], but the difficulty of working with such beams has kept scientists from fulfilling their potential as a research tool. Now a team at the Japan Proton Accelerator Research Complex (J-PARC) has successfully demonstrated the capability to manipulate a dense muon beam, accelerating the muons in a radio-frequency device for the first time [3].
Research from the University of St Andrews has set a new benchmark for the precision with which researchers can explore fundamental physics in quantum materials. The work has implications extending from materials science to advanced computing, as well as confirming a nearly 100-year-old prediction.
The researchers explored magnetoelastic coupling, which is the change in the size or shape of a material when exposed to a magnetic field. It is usually a small effect, but one that has technological consequences.
A team from the School of Physics and Astronomy at the University of St Andrews has now discovered that this effect is remarkably large in a case where one wouldn’t have expected it—in a transition metal oxide. Oxides are a chemical compound containing at least one oxygen atom and one other element in its chemical formula. High-temperature superconductors are one of the most prominent examples of a transition metal oxide.
In 1912, astronomer Victor Hess discovered strange, high-energy particles known as “cosmic rays.” Since then, researchers have hunted for their birthplaces. Today, we know about some of the cosmic ray “launch pads”, ranging from the Sun and supernova explosions to black holes and distant active galactic nuclei. What astronomers are now searching for are sources of cosmic rays within the Milky Way Galaxy.
In a pair of presentations at the recent American Astronomical Society meeting, a team led by Michigan State University’s Zhuo Zhang, proposed an interesting place where cosmic rays originate: a pulsar wind nebula in our own Milky Way Galaxy. A pulsar is a rapidly rotating neutron star, formed as a result of a supernova explosion. High-energy particles and the neutron star’s strong magnetic field combine to interact with the nearby interstellar medium. The result is a pulsar wind nebula that can be detected across nearly the whole electromagnetic spectrum, particularly in X-rays. It makes sense that this object would be a source of cosmic rays. Pulsars are found throughout the Galaxy, which makes them a useful category in the search for cosmic ray engines in the Milky Way.
The Vela Pulsar is a good example of a pulsar wind nebula. The pulsar is at the center, and the surrounding cloudiness is the nebula. Courtesy NASA.