Lifeboat Foundation

Quantum traffic laws applied to the 3D streetscape of a specific kind of crystal can put the brakes on electron rush hour.

In a search for novel materials that can contain bizarre new states of matter, physicists from Rice University in the US led an experiment that forced free-roaming electrons to stay in place.

While the phenomenon has been seen in materials where electrons are constrained to just two dimensions, this is the first time it’s been observed in a three-dimensional crystal metal lattice, known as a pyrochlore. The technique gives researchers a new tool for studying the less conventional activities of plucky, charge-carrying particles.

Condensed matter systems and photonic technologies are regularly used by researchers to create microscale platforms that can simulate the complex dynamics of many interacting quantum particles in a more accessible setting. Some examples include ultracold atomic ensembles in optical lattices, superconducting arrays, and photonic crystals and waveguides. In 2006 a new platform emerged with the demonstration of macroscopically coherent quantum fluids of exciton-polaritons to explore many-body quantum phenomena through optical techniques.

When a piece semiconductor is placed between two mirrors—an optical microresonator—the electronic excitations within can become strongly influenced by photons trapped between the mirrors. The resulting new bosonic quantum particles, known as exciton-polaritons (or polaritons for short), can under the right circumstances undergo a phase transition into a nonequilibrium Bose-Einstein condensate and form a macroscopic quantum fluid or a droplet of light.

Quantum fluids of polaritons have many salient properties, one being that they are optically configurable and readable, permitting easy measurements of the polariton dynamics. This is what makes them so advantageous to simulate many-body physics.

Universal behavior is a central property of phase transitions, which can be seen, for example, in magnets that are no longer magnetic above a certain temperature. A team of researchers from Kaiserslautern, Berlin and Hainan, China, has succeeded for the first time in observing such universal behavior in the temporal development of an open quantum system, a single cesium atom in a bath of rubidium atoms.

This finding helps to understand how quantum systems reach equilibrium. This is of interest to the development of quantum technologies, for example. The study has been published in Nature Communications.

Phase transitions in chemistry and physics are changes in the state of a substance, for example, the change from a liquid to a gaseous phase, when an external parameter such as temperature or pressure is changed.

Catalysts unlock pathways for chemical reactions to unfold at faster and more efficient rates, and the development of new catalytic technologies is a critical part of the green energy transition.

The Rice University lab of nanotechnology pioneer Naomi Halas has uncovered a transformative approach to harnessing the catalytic power of aluminum nanoparticles by annealing them in various gas atmospheres at high temperatures.

According to a study published in the Proceedings of the National Academy of Sciences, Rice researchers and collaborators showed that changing the structure of the oxide layer that coats the particles modifies their catalytic properties, making them a versatile tool that can be tailored to suit the needs of different contexts of use from the production of sustainable fuels to water-based reactions.

Most people know about solids, liquids, and gases as the main three states of matter, but a fourth state of matter exists as well. Plasma—also known as ionized gas—is the most abundant, observable form of matter in our universe, found in the sun and other celestial bodies.

Creating the hot mix of freely moving electrons and ions that compose a plasma often requires extreme pressures or temperatures. In these extreme conditions, researchers continue to uncover the unexpected ways that plasma can move and evolve. By better understanding the motion of plasma, scientists gain valuable insights into solar physics, astrophysics, and fusion.

In a paper published in Physical Review Letters, researchers from the University of Rochester, along with colleagues at the University of California, San Diego, discovered a new class of plasma oscillations—the back-and-forth, wave-like movement of electrons and ions. The findings have implications for improving the performance of miniature particle accelerators and the reactors used to create fusion energy.

A group of Tohoku University researchers has developed a theoretical model for a high-performance spin wave reservoir computing (RC) that utilizes spintronics technology. The breakthrough moves scientists closer to realizing energy-efficient, nanoscale computing with unparalleled computational power.

Details of their findings were published in npj Spintronics on March 1, 2024.

The brain is the ultimate computer, and scientists are constantly striving to create neuromorphic devices that mimic the brain’s processing capabilities, low power consumption, and its ability to adapt to neural networks. The development of neuromorphic computing is revolutionary, allowing scientists to explore nanoscale realms, GHz speed, with low energy consumption.

The challenge of regulating the electronic structures of metal single-atoms (M-SAs) with metal nanoparticles (M-NPs) lies in the synthesis of a definite architecture. Such a structure has strong electronic metal-support interactions and maintains electron transport channels to facilitate carbon dioxide photoreduction (CO₂PR).

In a study published in Advanced Powder Materials, a group of researchers from Zhejiang Normal University, Zhejiang A&F University and Dalian University of Technology, revealed the engineering of the electron density of Pd single atoms with twinned Pd nanoparticles assisted by strong electronic interaction of the atomic metal with the support and unveiled the underlying mechanism for expedited CO₂PR.

“As one of the most promising CO₂PR semiconductors, polymeric graphitic carbon nitride (g-C₃N₄) featured with sp² π-conjugated lamellar structures can offer electronegative nitrogen atoms to anchor M-SAs, forming active metal-nitrogen moieties (M–N_x),” explained Lei Li, lead author of the study. “However, stable M–N_x configurations forbid tunability of electronic structures of M-SA sites.”

The Isaac Newton Institute for Mathematical Sciences (INI) in Cambridge hosted a research programme on one of the most pressing problems in modern physics: to build a theory that can explain all the fundamental forces and particles of nature in one unifying mathematical framework. Such a theory of quantum gravity would combine two hugely successful frameworks on theoretical physics, which have so far eluded unification: quantum physics and Einstein’s theory of gravity.

The Black holes: bridges between number theory and holographic quantum information programme focusses on black holes, which play a hugely important part in this area, on something called the holographic principle, and on surprising connections to pure mathematics. This collection of articles explores the central concepts involved and gives you a gist of the cutting edge research covered by the INI programme.

Argonne’s Science 101 series takes you back to the basics, with plain-language explanations of the scientific concepts behind our pivotal discoveries and our biggest innovations.

In this Science 101 video, postdoctoral researchers Gillian Beltz-Mohrmann and Florian Kéruzoré explore two of the biggest mysteries in science: dark matter and dark energy. These strange influences seem to be stretching the universe apart and clumping stuff together in unexpected ways. Together, they make up a whopping 95% of the universe, but because we can’t see or touch them, we don’t know what they are.

Continue reading “Science 101: What are Dark Matter and Dark Energy?” »