Bachstetter, Spinal Cord and Brain Injury Research Center, Department of Neuroscience, University of Kentucky, 741 S. Limestone Street, BBSRB Room B459, Lexington, Kentucky 40536–0509, USA. Phone: 859.218.4315; Email: [email protected].
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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.
Five phases of localization physics observed in a single quantum system
Physicists in China have observed five phases in localization physics within a single quantum system. Using an advanced photonic platform, the team, led by Yucheng Wang and Jingyun Fan at the Southern University of Science and Technology, Shenzhen, has demonstrated that localization physics is likely far richer than physicists anticipated. Their results have been published in Physical Review Letters.
In 1958, American physicist Philip Anderson made the foundational discovery that disordered media are better at trapping waves than orderly lattice structures. Described mathematically by “localization phases,” this phenomenon now underpins our understanding of both condensed matter and wave physics.
So far, theory has distinguished between two distinct localization phases: one exhibiting “extended” states, which support wave transport, and the other associated with “localized” states, which suppress it. Yet through recent theoretical work, physicists uncovered a third distinct phase, named the “critical phase.”
How a brainless sea blob still ‘feels’ touch and crawls away in seconds without nerves or muscles
For a flat sea creature just a few millimeters across, a gentle poke is instantly recognized as danger. Trichoplax adhaerens—a translucent blob with no head, brain or muscles—scuttles away in seconds when touched. Imagine a flattened multicellular amoeba moving as a single unit: Trichoplax is only ~20 microns thick and a few millimeters wide. It glides on surfaces by beating tens of thousands of cilia on its lower epithelium (the underside), like microscopic oars dragging against the water.
Yet unlike most animals, Trichoplax has no obvious front or back end, no nerves or muscles at all. How can such a simple “crawling carpet” steer or change direction without a brain?
A new study reveals the remarkable flexibility of this pinhead-sized animal. While in most creatures, the orientation of each cilium is fixed early in development and locked to the body’s axes, Trichoplax achieves its swift escape by reorienting its thousands of hairlike cilia.
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.
A new way to control tiny quantum light sources by twisting atomically thin layers of hexagonal boron nitride
In a paper published in Science Advances, researchers at the University of Technology Sydney (UTS) in collaboration with the University of Minnesota and Kyung Hee University have found a new way to control quantum light sources, which is one of the key elements needed before quantum technologies can be used reliably in real-world systems.
Lead author Dr. Angus Gale says the research gives scientists a new control mechanism for tiny quantum light sources, bringing them a step closer to being used in practical quantum technologies such as quantum computing, secure communication and ultrasensitive sensing.
“You can measure these quantum emitters and see that they exist, but it’s hard to make them work in practice. This gives us a lever to get closer to that—a step toward the realization of quantum technologies,” said Dr. Gale.
Unpatchable ‘usbliter8’ Exploit Breaks Apple A12 and A13 SecureROM Boot Chain
Security researchers at Paradigm Shift have published a working exploit, dubbed usbliter8, that achieves arbitrary code execution inside the SecureROM of Apple’s A12 and A13 chips.
That code is burned into the silicon at manufacture. No software update can reach it. Affected devices will carry this flaw for as long as they stay in use.
This is not a remote attack. It requires physical possession of the device, which must be in DFU mode and connected via USB to a dedicated RP2350-based microcontroller board. With that setup, the exploit finishes in under two seconds, before Apple’s signed boot chain loads.