The authors demonstrate electrically pumped continuous-wave operation of a SiGeSn/GeSn lasers. The devices are based on a multi-quantum-well design in a small footprint micro-disk cavity resulting in driving parameters compatible with on-chip operation.
Frequency-scanning systems with narrow instantaneous linewidth hold promise for various fields. Here, the authors report the use of time-variant parity-time symmetry to dynamically narrow the instantaneous linewidth of frequency-scanning systems.
A new study by Rice University physicist Qimiao Si unravels the enigmatic behaviors of quantum critical metals—materials that defy conventional physics at low temperatures. Published in Nature Physics Dec. 9, the research examines quantum critical points (QCPs), where materials teeter on the edge between two distinct phases, such as magnetism and nonmagnetism. The findings illuminate the peculiarities of these metals and provide a deeper understanding of high-temperature superconductors, which conduct electricity without resistance at relatively high temperatures.
Key to this study is quantum criticality, a delicate state where the material becomes ultrasensitive to quantum fluctuations—microscopic disturbances that alter electron behavior. While ordinary metals obey well-established principles, quantum critical metals defy these norms, exhibiting strange and collective properties that have long puzzled scientists. Physicists call such systems “strange metals.”
“Our work dives into how quasiparticles lose their identity in strange metals at these quantum critical points, which leads to unique properties that defy traditional theories,” said Si, the Harry C. and Olga K. Wiess Professor of Physics and Astronomy and director of Rice’s Extreme Quantum Materials Alliance.
Current optical skyrmion generators involve complex bulky systems, hindering further practical applications. We propose an integrated metafiber for high-quality photonic skyrmions, with subwavelength polarization features and topology tunability.
A team of researchers from the University of Cologne, Hasselt University (Belgium) and the University of St Andrews (Scotland) has succeeded in using the quantum mechanical principle of strong light-matter coupling for an optical technology that overcomes the long-standing problem of angular dependence in optical systems.
The study, “Breaking the angular dispersion limit in thin film optics by ultra-strong light-matter coupling,” published in Nature Communications presents ultra-stable thin-film polariton filters that open new avenues in photonics, sensor technology, optical imaging and display technology.
The study at the University of Cologne was led by Professor Dr. Malte Gather, director of the Humboldt Center for Nano-and Biophotonics at the Department of Chemistry and Biochemistry of the Faculty of Mathematics and Natural Sciences.
Researchers have discovered that old elliptical galaxies can form from intense star formation in early galaxy cores.
This finding, derived from data analyzed by the Atacama Large Millimeter/submillimeter Array, shows that these spheroidal galaxies, often considered static and inert, were once dynamic regions of intense star formation during the cosmic noon. This transformative view on galaxy evolution helps clarify the processes behind the formation of the universe’s most massive galaxies.
Groundbreaking Discovery in Galaxy Formation.
NASAs new Landolt mission, launching in 2029, will orbit an artificial star around Earth to enhance stellar and planetary measurements.
This will improve the accuracy of stellar brightness calculations by over ten times, aiding in our understanding of planets orbiting these stars and providing insights into dark energy.
The Landolt Mission
Imagine this: a round, plump robot, like a giant bowling ball, that can roll on land, swim in water, and perform all sorts of high-tech operations. On October 9th, a team of scientists from Zhejiang University unveiled something called the RT-G spherical robot, claiming it’s a \.
The Hénon map: a two-dimensional map that sheds light on the fractal structure of strange attractors. Deriving the Hénon map. Analyzing the map. Simulations.
Reading: Strogatz, \
