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It’s not easy making green.

For years, scientists have fabricated small, high-quality lasers that generate red and blue light. However, the method they typically employ — injecting electric current into semiconductors — hasn’t worked as well in building tiny lasers that emit light at yellow and green wavelengths. Researchers refer to the dearth of stable, miniature lasers in this region of the visible-light spectrum as the “green gap.” Filling this gap opens new opportunities in underwater communications, medical treatments and more.

Compact laser diodes can emit infrared, red and blue wavelengths, but are highly inefficient at producing green and yellow wavelengths, a region known as the ‘green gap’. (Image: S. Kelley, NIST)

Quantum magnets are materials that realize a quantum superposition of magnetic states, bringing quantum phenomena from the microscopic to the macroscopic scale. These materials feature exotic quantum excitations–including fractional excitations where electrons behave as if they were split into many parts–that do not exist anywhere outside of this material.

To manipulate how the atoms behaved inside the quantum material the researchers had assembled, they poked each individual atom with a tiny needle. This technique allows for the accurate probing of qubits at the atomic level. The needle, in reality an atomically sharp metal tip, served to excite the atoms’ local magnetic moment, which resulted in topological excitations with enhanced coherence.

“Topological quantum excitations, such as those realized in the topological quantum magnet we now built, can feature substantial protection against decoherence. Ultimately, the protection offered by these exotic excitations can help us overcome some of the most pressing challenges of currently available qubits,” Lado says.

How would atoms behave near a supermassive object? We know how atoms behave in extremely weak gravity like that at the Earth’s surface: They can be excited from a lower energy level to a higher one when an electron absorbs a photon or a nucleus absorbs a gamma ray, and so on. But what if the atom is in a strong gravitational field such as one near a supermassive, rotating black hole or rotating neutron star?

Researchers at the Department of Energy’s SLAC National Accelerator Laboratory have uncovered new insights into the fundamental mechanisms of RNA polymerase II (Pol II), the protein responsible for transcribing DNA into RNA. Their study shows how the protein adds nucleotides to the growing RNA chain. The results, published in Proceedings of the National Academy of Sciences, have potential applications in drug development.

In the development of particle physics, researchers have introduced an innovative particle encoding mechanism that promises to improve how information in particle physics is digitally registered and analyzed. This new method, focusing on the quantum properties of constituent quarks, offers unprecedented scalability and precision. It paves the way for significant advancements in high-energy experiments and simulations.

Researchers have developed a technique to trap light within an organic material, forming a hybrid quantum state that gives rise to novel physical and chemical properties.

An international team of researchers led by the University of Ottawa has gone back to the kitchen cupboard to create a recipe that combines organic material and light to create quantum states.

Professor Jean-Michel Ménard, leader of the Ultrafast Terahertz Spectroscopy group at the Faculty of Science, coordinated with Dr. Claudiu Genes at the Max Planck Institute for the Science of Light (Germany), and with Iridian Spectral Technologies (Ottawa) to design a device which can efficiently modify properties of materials using the quantum superposition with light.