By probing the Universe on atomic scales and smaller, we can reveal the entirety of the Standard Model, and with it, the quantum Universe.
Category: particle physics
Tiny objects swimming in a superfluid of light move against the flow
Superfluids are intriguing states of matter in which particles behave like a giant collective wave, allowing them to flow without any friction. When this fluid flows past a fixed obstacle at a velocity below a specific threshold, it moves around it without slowing down or exerting any drag. Above this critical velocity, however, the superfluid state starts to break down, and the energy from the flow dissipates in the form of ripples and vortices in the fluid.
Researchers at Sorbonne University, the University of Porto, Côte d’Azur University and Paris-Saclay University recently investigated this phenomenon in a superfluid of light, a system in which light behaves like a superfluid. Their paper, published in Physical Review Letters, shows that under specific conditions, a mobile obstacle in a superfluid of light can start swimming against the flow.
“Our project naturally came about as a collaborative effort to bridge theory and experiment, sparked during joint discussions when Pierre-Élie Larré, now at LPTMS in Paris-Saclay, visited our lab in 2022,” Quentin Glorieux, co-senior author of the paper, told Phys.org.
15-atom Iridium Nanoclusters Stay Stable 20 Hours, Outperform Commercial Catalysts
An international research team from Tohoku University, Tokyo University of Science, Vanderbilt University and the University of Adelaide has discovered a novel, exceptionally simple method to precisely synthesize extremely small iridium nanoclusters in ambient air. Such a feat was previously considered highly challenging. In addition, the nanoclusters outperform conventional, commercially available iridium catalysts by 1.5 times in mass activity, while maintaining sustained operational stability without degradation for more than 20 hours.
This breakthrough could result in improved production of green hydrogen, which is considered the ultimate clean fuel. The findings were published in the Journal of the American Chemical Society.
The Oxygen Evolution Reaction (OER) can create green hydrogen, but the reaction requires so much energy that producing green hydrogen efficiently is a huge challenge. Furthermore, because the reaction takes place in a highly corrosive, strongly acidic environment, iridium (Ir) is virtually the only rare and expensive catalyst capable of enduring it.
What’s New in Science: Cosmic Surprises, Newton Supreme, A New Collider, and Feynman Dines Out?
I think this was one of my most enjoyable dialogues in our What’s new series. Maybe Sabine and I are getting more used to each other’s cadence and interests or maybe it was the subject matter. Either way, I think you will find this to be a fascinating and provocative discussion of science at the forefront, and at the not-so-forefront, because that science is interesting too! We began our discussion describing a new finding of a Giant Ring of galaxies billions of light years across in the sky. The key questions are: Is it real? And is it surprising? We both have slightly different takes on this. Next we described a new measurement of the strength of gravity on scales from 80 to 800 million light years in distance. And guess what? Gravity falls off just like Newton predicted! This may seem like a big yawn, but one of the most popular models that claims to do away with dark matter would imply that Gravity would fall off differently on these scales. Does this new result kill that idea? Stay tuned. Microsoft, which has cried wolf a number of times so far when it comes to something called Majorana qubits as the basis of a new viable quantum computer just published a new paper claiming they finally have it. Sabine and I discuss why we are both still skeptical, but why the effort is worth it. Next, CERN, the large European particle physics laboratory, and the world particle physics community seem to have converged on plans for building a huge new accelerator in the current CERN site… this time involving an underground ring 91 km in circumference, in which electrons and positrons would collide to explore the detailed properties of the Higgs particle. Is the effort worth it? Again, Sabine and I have slightly different takes on this. Fusion power, which we have talked about in a number of earlier episodes, continues to tempt humanity with the promise of unlimited energy. Many people, myself included, have tended to argue that fusion seems to be 25 years in the future, and may always be 25 years in the future. But many new efforts are underway, so who knows. Unfortunately, a group of economists has analyzed fusion in the context of other large energy programs and have argued that even if we can achieve it, it may not be as economically viable as many claim. Finally, one day Richard Feynman went to a Thai restaurant with his young companion Ralph Leighton, and wondered what he should order. Should it be the same old dish he loved or something new. An equation filled napkin later, and he had the answer. Fifty years later some cognitive scientists resurrected Feynman’s napkin and explained it, and argued it might have important implications in other social situations. Such is the power of science. Consider supporting the podcast and the Origins Project Foundation at https://www.originsproject.org/ To see commercial-free, full HD video episodes, join us at lawrence krauss.substack.com Thank you for your support! iTunes: https://podcasts.apple.com/us/podcast… https://TheOriginsPodcast.com Twitter: / theoriginspod Instagram:
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/ theoriginspod The Origins Podcast, a production of The Origins Project Foundation, features in-depth conversations with some of the most interesting people in the world about the issues that impact all of us in the 21st century. Host, theoretical physicist, lecturer, and author, Lawrence M. Krauss, will be joined by guests from a wide range of fields, including science, the arts, and journalism. The topics discussed on The Origins Podcast reflect the full range of the human experience — exploring science and culture in a way that seeks to entertain, educate, and inspire. Full Episodes Playlist:
• Ricky Gervais — The Origins Podcast with L…
Hidden electric space waves are quietly cleaning Earth’s ‘killer’ electrons
High above our heads, a silent battle is unfolding within Earth’s magnetic shield. For decades, scientists have tracked “killer electrons”—ultrafast particles capable of piercing satellite armor and endangering astronauts as they zip through the Van Allen radiation belts. While we knew these dangerous particles eventually leak out of the belts and into the atmosphere, the primary mechanism “cleaning” the highest-energy electrons has remained a persistent mystery of space weather.
Now, a study published in Geophysical Research Letters has uncovered the culprit by diving into three years of NASA’s Van Allen Probes data. Led by Lixian Yang and a team of researchers, the study identifies a hidden population of chorus waves that defies standard physics models.
Unlike typical space waves that are mostly magnetic, these highly oblique quasi-electrostatic (HOQE) waves possess an electric field so powerful it dominates their character. This unique electric punch allows them to knock electrons with energies up to 2 MeV out of orbit and into the atmosphere, scattering them with a force far more potent than any previous model predicted.
Out-of-equilibrium cesium atoms reveal fractional Fermi seas, exposing new critical quantum phase
In a new study published in Physical Review Letters, a team from the Nägerl group, together with theory collaborator Alvise Bastianello from the CNRS and the Université Paris-Dauphine, demonstrates that highly unusual quantum states known as “fractional Fermi seas” can be quantum engineered.
By driving quantum particles—here, ultracold cesium atoms under one-dimensional confinement—far out of equilibrium through cyclic changes of the particle interaction, a novel critical phase of matter emerges, going beyond what is known from the celebrated Tomonaga-Luttinger liquid theory. The new publication serves as the theoretical companion to, and foundation for, recent experimental work in the group of Hanns-Christoph Nägerl at the Department of Experimental Physics.
Usually, particles in the quantum world follow strict rules about how they organize themselves at low temperatures. As Bastianello explains, “Fermions, for instance, stack neatly into the available energy states to form the so-called ‘Fermi sea.’ But what happens if one forces interacting atoms to continuously cycle through extreme conditions, smoothly shifting them from strongly repelling each other to strongly attracting each other?”
Diamond-based particle detector captures one-picosecond electron bursts for high-rate beam diagnostics
Physicists at UC Santa Cruz and other institutes across California and New Mexico have developed a detection system that will allow next-generation particle accelerators to better reveal fundamental biological and chemical processes, as well as advance critical areas such as materials science and energy research.
The Advanced Accelerator Diagnostics Collaboration, a group of two University of California campuses and three U.S. national laboratories, came together to solve a growing need for high-rate beam diagnostics. These accelerators will now jump from 120 pulses a second to 1 million pulses a second, straining current beam diagnostic systems. The results are now published in the journal Physical Review Accelerators and Beams.
“It really highlights the power of collaboration between universities and national laboratories,” said Bruce Schumm, the Long Family Professor of Experimental Physics. “If you took away Lawrence Berkeley Lab, if you took away Los Alamos, if you took away UC Davis, any of those, the whole thing would have fallen apart.”
How do flocking birds and schools of fish move? New research offers crystal-clear answer
Flocking birds and schools of fish are a familiar sight. While previous research has uncovered the broad dynamics driving these movements, their underlying intricacies remain a mystery. Now a study by a team of New York University mathematicians offers new insights into these phenomena. It reveals that flocks and schools behave in ways similar to a soft crystalline material, with individual birds and fish serving as “atoms” that are evenly spaced in a lattice-like formation.
The findings, reported in the journal Physical Review Fluids, offer detailed insights into the hydrodynamic and aerodynamic interactions crucial in aerospace and automotive engineering, robotics and energy harvesting.
“Our findings offer a new way to understand how animal collectives coordinate movement and respond to their environment,” says Christiana Mavroyiakoumou, a researcher at NYU’s Courant Institute School of Mathematics, Computing, and Data Science at the time of the study and now a fellow at Oxford University’s Mathematical Institute. “More specifically, lines of birds or fish behave like an elastic material with regularly spaced individuals held together by flexible, or spring-like, bonds—akin to soft crystalline substances in which atoms are arranged in an orderly, repeating pattern.”
Electrically tunable spin polarization in graphene opens path toward low-power spintronic devices
Researchers at the National Graphene Institute, in collaboration with the National University of Singapore, have shown that the magnetic behavior of electrons in graphene can be precisely controlled using electricity, revealing unusually large spin signals in a carefully engineered graphene system.
The study, published in Nature Communications, demonstrates how placing graphene close to a magnetic material can influence the spin of electrons without permanently altering graphene itself. By combining this magnetic proximity effect with graphene superlattices and operating at very low charge densities, the researchers were able to strongly tune how spins move through the material.
“This work shows that by combining graphene with nearby magnetic materials, we can gain a high level of control over electron spin using electrical signals alone,” said Dr. Daniel Burrow, from the University of Manchester. “In simple terms, we are learning how to pass information through graphene using the spin of electrons rather than their electrical charge.”