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Researchers from Skoltech and the University of Cambridge have shown that polaritons, the quirky particles that may end up running the quantum supercomputers of the future, can form structures behaving like molecules - and these artificial molecules can potentially be engineered on demand. The paper outlining these results was published in the journal
Physical Review B Letters.
Polaritons are quantum particles that consist of a photon and an exciton, another quasiparticle, marrying light and matter in a curious union that opens up a multitude of possibilities in next-generation polaritonic devices. Alexander Johnston, Kirill Kalinin and Natalia Berloff, professor at the Skoltech Center for Photonics and Quantum Materials and University of Cambridge, have shown that geometrically coupled polariton condensates, which appear in semiconductor devices, are capable of simulating molecules with various properties.
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IMAGE: Cell membranes contain channels that selectively permit ions to move into or out of the cell. In a recently published paper, researchers from the University of Fukui and Kanazawa University. view more
Credit: University of Fukui
The cell membranes of all organisms contain ion channels that permit ions to pass into or out of the cell, and these channels play extremely important roles in fundamental physiological processes such as heartbeats and the rapid conduction of signals along neurons. An important property of these ion channels is their selective conductivity they selectively permit the passage of particular ions. For example, potassium channels more readily permit the passage of potassium ions than the passage of sodium ions, despite the fact that potassium ions are larger.
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IMAGE: Spin texture of a second-order half-skyrmion (meron) on the surface of a birefringent cavity. (Source: Physics UW, M. Krol) view more
Credit: Source: Physics UW, M. Krol
The scientists have demonstrated how to structure light such that its polarization behaves like a collective of spins in a ferromagnet forming half-skyrmion (also known as merons). To achieve this the light was trapped in a thin liquid crystal layer between two nearly perfect mirrors. Skyrmions in general are found, e.g., as elementary excitations of magnetization in a two-dimensional ferromagnet but do not naturally appear in electromagnetic (light) fields.
One of the key concepts in physics, and science overall is the notion of a field which can describe the spatial distribution of a physical quantity. For instance, a weather map shows the distributions of temperature and pressure (these are known as scalar fields), as well as the wind speed and direction (known as a vector field).
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IMAGE: An initial crack in a film creates a RVPB (a). A second crack event in the film (b) causes a collapse front to be formed which sweeps up the RVPB. view more
Credit: Tokyo Metropolitan University
Tokyo, Japan - Researchers from Tokyo Metropolitan University have revealed how liquid foams collapse by observing individual collapse events with high-speed video microscopy. They found that cracks in films led to a receding liquid front which sweeps up the original film border, inverts its shape, and releases a droplet which hits and breaks other films. Their observations and physical model provide key insights into how to make foams more or less resistant to collapse.
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IMAGE: The amyloid beta protein that tangles to form the hallmark Alzheimer s brain plaques, cling to ultra-small bowls, called nanobowls, scientists find. They can use these nanobowls to remove the toxic. view more
Credit: Illustration courtesy of Vrinda Sant.
ROCKVILLE, MD - Scientists are still a long way from being able to treat Alzheimer s Disease, in part because the protein aggregates that can become brain plaques, a hallmark of the disease, are hard to study. The plaques are caused by the amyloid beta protein, which gets misshapen and tangled in the brain. To study these protein aggregates in tissue samples, researchers often have to use techniques that can further disrupt them, making it difficult to figure out what s going on. But new research by Vrinda Sant, a graduate student, and Madhura Som, a recent PhD graduate, in the lab of Ratnesh Lal at the University of California, San Diego, provides a new technique for studying amyloid beta and could be