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Tellurium boosts 2D semiconductor performance for faster photodetection

A group of Carnegie Mellon University researchers recently devised a method allowing them to create large amounts of a material required to make two-dimensional (2D) semiconductors with record high performance. Their paper, published in ACS Applied Materials & Interfaces in late December 2024, could lead to more efficient and tunable photodetectors, paving the way for the next generation of light-sensing and multifunctional optoelectronic devices.

“Semiconductors are the key enabling technology for today’s electronics, from laptops to smartphones to AI applications,” said Xu Zhang, assistant professor of electrical and computer engineering. “They control the flow of electricity, acting as a bridge between conductors (which allow electricity to flow freely) and insulators (which block it).”

Zhang’s research group wanted to develop a certain kind of photodetector, a device capable of detecting light and which can be used in a variety of applications. To create this photodetector, the group needed to use materials that were an atom’s-width thick, or as close to 2D as is possible.

Graphene quantum dots mimic orbital hybridization

A research team led by Professor Sun Qing-Feng in collaboration with Professor He Lin’s research group from Beijing Normal University has achieved orbital hybridization in graphene-based artificial atoms for the first time.

Their study, titled “Orbital hybridization in graphene-based artificial atoms” has been published in Nature. The work marks a significant milestone in the field of quantum physics and , bridging the gap between artificial and real atomic behaviors.

Quantum dots, often called artificial atoms, can mimic but have not yet been used to simulate orbital hybridization, a crucial process in real atoms. While quantum dots have successfully demonstrated artificial bonding and antibonding states, their ability to replicate orbital hybridization remained unexplored.

Quantum sensing achieves unprecedented precision in light displacement detection

A study led by the University of Portsmouth has achieved unprecedented precision in detecting tiny shifts in light displacements at the nanoscale. This is relevant in the characterization of birefringent materials and in high-precision measurements of rotations.

The quantum sensing breakthrough is published in the journal Physical Review A, and has the potential to revolutionize many aspects of daily life, industry, and science.

Imagine two photons, massless particles of light, that are intertwined in a unique way, meaning their propagation is connected even when they are separated. When these photons pass through a device that splits the particles of light into two paths—known as a beam-splitter—they interfere with each other in special patterns. By analyzing these patterns, researchers have developed a highly precise method to detect even the tiniest initial spatial shifts between them.

Muonic atoms unlock new possibilities in nuclear physics

University of Queensland researchers have made a breakthrough in muonic atom research, clearing the way for new nuclear physics experiments.

A team at the UQ School of Mathematics and Physics has combined theory and experiments to show that nuclear polarization does not limit studies of muonic atoms. The research was published in Physical Review Letters.

Co-author Dr. Odile Smits said the finding provides a clear path for using muonic atoms to better understand the magnetic structure of the .

Quantum ‘Tornadoes’ Spotted in Semimetal May Redefine Electronics

Physicists in Germany have led experiments that show the inertia of electrons can form ‘tornadoes’ inside a quantum semimetal.

It’s almost impossible for electrons to sit still, and their motions can take on some bizarre forms. Case in point: an analysis of electron behavior in a quantum material called tantalum arsenide reveals vortices.

But the story gets weirder. These electrons aren’t spiraling in a physical place – they’re doing so in a quantum blur of possibility called momentum space. Rather than drawing a map of particles potential locations, or position space, momentum space describes their motion through their energy and direction.

Mediterranean neutrino observatory sets new limits on quantum gravity

Quantum gravity is the missing link between general relativity and quantum mechanics, the yet-to-be-discovered key to a unified theory capable of explaining both the infinitely large and the infinitely small. The solution to this puzzle might lie in the humble neutrino, an elementary particle with no electric charge and almost invisible, as it rarely interacts with matter, passing through everything on our planet without consequences.

For this very reason, neutrinos are difficult to detect. However, in rare cases, a neutrino can interact, for example, with water molecules at the bottom of the sea. The particles emitted in this interaction produce a “blue glow” known as Čerenkov radiation, detectable by instruments such as KM3NeT.

The KM3NeT (Kilometer Cube Neutrino Telescope) is a large underwater observatory designed to detect neutrinos through their interactions in water. It is divided into two detectors, one of which, ORCA (Oscillation Research with Cosmics in the Abyss), was used for this research. It is located off the coast of Toulon, France, at a depth of approximately 2,450 meters.

Understanding Wheeler’s “It from Bit” Concept

John Archibald Wheeler was one of the most daring thinkers in twentieth-century physics, famed for his deep insights into quantum mechanics, general relativity, and the nature of information. In his classic essay on “It from Bit,” Wheeler proposed that at the heart of reality lies a fundamentally informational thread. This means that rather than starting with “things” — material objects with an independent existence — one might instead begin with “bits,” the discrete units of information that become “real” only when observed. Within this sweeping vision, the observer plays a crucial role in bringing the universe into a definite existence, and information takes center stage in shaping the very character of physical phenomena.

In broad strokes, Wheeler’s idea of “It from Bit” emerges from the curious interplay between the quantum world and classical objects. At the core of quantum mechanics is the principle that measuring or observing something at the microscopic scale affects its state. According to the standard interpretation, a system in a so-called superposition will “collapse” into a particular outcome when measured. Wheeler’s bold claim was that this phenomenon illuminates a more general fact: that information, not matter, might be the building block of reality. Thus, any physical “it” — an electron, a planet, or even the entire cosmos — ultimately grows from answers to yes/no questions (bits), shaped by acts of measurement. Put more simply, Wheeler wanted us to see the world as not built out of little billiard-ball-like atoms existing in some absolute manner, but out of meaningful acts of observation that yield discrete bits of data.

Behind this elegant concept lies a deep philosophical backdrop. Wheeler urged us to ponder how the universe came to be what it is, and why. If we trace everything back to an early cosmos, we arrive at a place where only quantum possibilities existed — no fixed table of facts and objects. Gradually, so his argument goes, as the universe evolved and observers emerged, questions got asked, measurements were made, bits of information accumulated, and reality “crystallized.” This leap from quantum weirdness to classical solidity thus becomes a grand puzzle about information. Rather than letting classical physics occupy center stage from the beginning, Wheeler reversed the script: quantum possibilities plus acts of observation define and generate the classical world we experience. In this sense, the cosmic stage is incomplete without the audience, and reality only stabilizes by virtue of these repeated question-and-answer interactions.

Gauging the Temperature Sensitivity of a Nuclear Clock

Researchers have characterized the temperature-induced frequency shifts of a thorium-229 nuclear transition—an important step in establishing thorium clocks as next-generation frequency standards.

Atomic clocks are at the core of many scientific and technological applications, including spectroscopy, radioastronomy, and global navigation satellite systems. Today’s most precise devices—based on electronic transitions in atoms—would gain or lose less than 1 second over the age of the Universe. An even more accurate timekeeping approach has recently emerged, based on a clock ticking at the frequency of a nuclear transition of the isotope thorium-229 (229 Th) [1, 2]. Now a collaboration between the teams of Jun Ye of JILA, the National Institute of Standards and Technology, and the University of Colorado Boulder and of Thorsten Schumm of the Vienna Center for Quantum Science and Technology has characterized one of the main sources of the systematic uncertainties that might spoil a clock’s accuracy: temperature-induced shifts of the clock transition frequency [3].