Unifying machine learning and physics.
In this video, Dr. Ardavan (Ahmad) Borzou will discuss the history of unifications in physics and how we can unify physics and machine learning.
Continue reading “Unifying Physics and Machine Learning: The Next Big Breakthrough?” »
How do you find and measure nuclear particles, like antineutrinos, that travel near the speed of light?
Antineutrinos are the antimatter partner of a neutrino, one of nature’s most elusive and least understood subatomic particles. They are commonly observed near nuclear reactors, which emit copious amounts of antineutrinos, but they also are found abundantly throughout the universe as a result of Earth’s natural radioactivity, with most of them originating from the decay of potassium-40, thorium-232 and uranium-238 isotopes.
When an antineutrino collides with a proton, a positron and a neutron are produced—a process known as inverse beta decay (IBD). This event causes scintillating materials to light up, making it possible to detect these antineutrinos; and if they can be detected, they can be used to study the properties of a reactor’s core or Earth’s interior.
At night, charged particles from the sun caught by Earth’s magnetosphere rain down into the atmosphere. The impacting particles rip electrons from atoms in the atmosphere, creating both beauty and chaos. These high-energy interactions cause the northern and southern lights, but they also scatter radio signals, wreaking havoc on ground-based and satellite communications.
Scientists would like to track electrical activity in the ionosphere by measuring the distribution of plasma, the form matter takes when positive ions are separated from their electrons, to help better predict how communications will be affected by electromagnetic energy.
But analyzing plasma in the ionosphere is a challenge because its distribution changes quickly and its movements are often unpredictable. In addition, collisional physics makes detecting true motion in the lower ionosphere exceedingly difficult.
In the quest for ultra-precise timekeeping, scientists have turned to nuclear clocks. Unlike optical atomic clocks—which rely on electronic transitions—nuclear clocks utilize the energy transitions in the atom’s nucleus, which are less affected by outside forces, meaning this type of clock could potentially keep time more accurately than any previously existing technology.
However, building such a clock has posed major challenges—thorium-229, one of the isotopes used in nuclear clocks, is rare, radioactive, and extremely costly to acquire in the substantial quantities required for this purpose.
Reported in a study published in Nature, a team of researchers, led by JILA and NIST Fellow and University of Colorado Boulder Physics professor Jun Ye, in collaboration with Professor Eric Hudson’s team at UCLA’s Department of Physics and Astronomy, have found a way to make nuclear clocks a thousand times less radioactive and more cost-effective, thanks to a method creating thin films of thorium tetrafluoride (ThF4).
MIT physicists have created a new and long-lasting magnetic state in a material, using only light.
In a study that appears in Nature, the researchers report using a terahertz laser —a light source that oscillates more than a trillion times per second—to directly stimulate atoms in an antiferromagnetic material. The laser’s oscillations are tuned to the natural vibrations among the material’s atoms, in a way that shifts the balance of atomic spins toward a new magnetic state.
The results provide a new way to control and switch antiferromagnetic materials, which are of interest for their potential to advance information processing and memory chip technology.
Atomic simulations deepen the mystery of how engineered materials known as refractory high-entropy alloys can suffer so little damage by radiation.
Refractory high-entropy alloys are materials made from multiple high-melting-point metals in roughly equal proportions. Those containing tungsten exhibit minimal changes in mechanical properties when exposed to continuous radiation and could be used to shield the crucial components of future nuclear reactors. Now Jesper Byggmästar and his colleagues at the University of Helsinki have performed atomic simulations that explore the uncertain origins of this radiation resistance [1]. The findings could help scientists design novel materials that are even more robust than these alloys in extreme environments.
The researchers studied a tungsten-based refractory high-entropy alloy using state-of-the-art simulations guided by machine learning. In particular, they modeled the main mechanism by which radiation can disrupt such an alloy’s atomic structure. In this mechanism, the incoming radiation causes one atom in the alloy to displace another atom, forming one or more structural defects. The team determined the threshold energy needed to induce such displacements and its dependence on the masses of the two involved atoms.
A laser-driven electron accelerator delivers beams of 10-GeV electrons—an approach that could lead to cheaper, more compact alternatives to large-scale x-ray sources and particle accelerators.
In the early moments following the Big Bang, matter and antimatter should have been created in equal amounts. However, 13.8 billion years later, the Universe is overwhelmingly made of matter, with antimatter nearly absent. This strange imbalance has baffled scientists for decades, hinting that something must have occurred to tilt the balance in favor of matter.
One of the leading theories to explain this disparity is charge–parity (CP) violation, a phenomenon predicted by the Standard Model of particle physics. CP violation refers to a small but measurable difference in how matter and antimatter behave.
However, the Standard Model predicts that the number of CP violations is far too small to account for the vast predominance of matter. So far, CP violation has only been observed in certain particle decays, notably in mesons — particles made of quarks and an antiquark. To truly understand the origins of the matter-antimatter imbalance, scientists need to see CP violation in a broader range of particles, particularly baryons, composed of three quarks.
Newly discovered altermagnetism at the Swiss Light Source SLS opens door to new physics & spintronics. Learn about this new addition to magnetic family!
The LOREX experiment utilizes lorandite ore to gauge historical solar neutrino flux, revealing insights about the Sun’s development and climatic effects through advanced decay rate measurements.
The Sun, Earth’s life-sustaining powerhouse, generates immense energy through nuclear fusion while emitting a steady stream of neutrinos — subatomic particles that reveal its inner workings. While modern neutrino detectors shed light on the Sun’s current behavior, key questions remain about its stability over millions of years — a timeframe encompassing human evolution and major climate changes.
Addressing these questions is the mission of the LORandite EXperiment (LOREX), which depends on accurately determining the solar neutrino cross-section for thallium. An international team of scientists has now achieved this crucial measurement using the unique Experimental Storage Ring (ESR) at GSI/FAIR in Darmstadt. Their groundbreaking results, advancing our understanding of the Sun’s long-term stability, have been published in the journal Physical Review Letters.
