… new model explains 3D quantum material. Scientists from the Cluster of Excellence ct.qmat – Complexity and Topology in Quantum Matter have developed a new understanding of how electrons behave in strong magnetic fields. Their results explain measurements of electric currents in three-dimensional materials that signal a quantum Hall effect – a phenomenon thus far only associated with two-dimensional metals. This new 3D effect can be the foundation for topological quantum phenomena, which are believed to be particularly robust and…
AMOLF scientists unravel noise-assisted signal amplification in systems with memory. Signals can be amplified by an optimum amount of noise, but this so-called stochastic resonance is a rather fragile phenomenon. Researchers at AMOLF were the first to investigate the role of memory for this phenomenon in an oil-filled optical microcavity. The effects of slow non-linearity (i.e. memory) on stochastic resonance were never considered before, but these experiments suggest that stochastic resonance becomes robust to variations in the signal frequency when…
Metasurface holograms (meta-holograms) are ultra-thin artificial surfaces designed to shape incident light and project it to extremely wide angles. Meta-holograms have opened up numerous possibilities such as light multiplexing, information processing, 3D display, high-density data storage, and optical encoding. Despite of these remarkable advances, the road to practical applications of meta-holograms is hindered by artifacts that originate from strong interactions between the building blocks of the meta-holographic surface and inevitable fabrication defects, ultimately causing distortion and degradation to the holographic…
Discovered by Victor Hess in 1912, cosmic rays, relativisitic particles that shower Earth, contribute a signicant part of the energy density in the universe and carries unambiguous informations on various astrophysical processes . Yet until now, origin of cosmic rays is still a mystery. A key problem in understanding the origin of cosmic rays is the searching for the acceleration site up to or even beyond Ultra-high energy (UHE). Such extreme accelerators are dubbed as PeVatrons. However, composed of subatomic…
Radio telescope images enable a new way to study magnetic fields in galaxy clusters millions of light years away. For the first time, researchers have observed plasma jets interacting with magnetic fields in a massive galaxy cluster 600 million light years away, thanks to the help of radio telescopes and supercomputer simulations. The findings, published in the journal Nature, can help clarify how such galaxy clusters evolve. Galaxy clusters can contain up to thousands of galaxies bound together by gravity….
A research team from TU Wien together with US research institutes came across a surprising form of ‘quantum criticality’; this could lead to a design concept for new materials. In everyday life, phase transitions usually have to do with temperature changes – for example, when an ice cube gets warmer and melts. But there are also different kinds of phase transitions, depending on other parameters such as magnetic field. In order to understand the quantum properties of materials, phase transitions…
The model can better predict the physical phenomenon inside of very-high-temperature pebble-bed reactors. When one of the largest modern earthquakes struck Japan on March 11, 2011, the nuclear reactors at Fukushima-Daiichi automatically shut down, as designed. The emergency systems, which would have helped maintain the necessary cooling of the core, were destroyed by the subsequent tsunami. Because the reactor could no longer cool itself, the core overheated, resulting in a severe nuclear meltdown, the likes of which haven’t been seen…
Astronomers using NASA’s Hubble Space Telescope have traced the locations of five brief, powerful radio blasts to the spiral arms of five distant galaxies. Called fast radio bursts (FRBs), these extraordinary events generate as much energy in a thousandth of a second as the Sun does in a year. Because these transient radio pulses disappear in much less than the blink of an eye, researchers have had a hard time tracking down where they come from, much less determining what…
Scientists at Goethe University Frankfurt and the Event Horizon Telescope Collaboration use data which produced the first image of a black hole to constrain its fundamental properties. Theoretical physicists at Goethe University Frankfurt have analysed data from the black hole M87* as part of the Event Horizon Telescope (EHT) collaboration to test Albert Einstein’s theory of general relativity. According to the tests, the size of the shadow from M87* is in excellent agreement being from a black hole in general…
Researchers from Friedrich Schiller University Jena, the University of California Berkeley and the Institut Polytechnique de Paris use intense laser light in the extreme ultraviolet spectrum to generate a non-linear optical process on a laboratory scale – a process which until now has only been possible in a large-scale research facility. As the team writes in the current issue of the journal “Science Advances”, they were able to achieve this effect for the first time with a laser source on…
A chip-compatible 3D nanoscopy answers. Compared with the superresolution microscopy that bases on squeezing the point spread function in the spatial domain, the superresolution microscopy that broadens the detection range in the spatial frequency domain through the spatial-frequency-shift (SFS) effect shows intriguing advantages including large field of view, high speed, and good modularity, owing to its wide-field picture acquisition process and universal implementation without using special fluorophores labeling. To enable spatial-frequency-shift microscopy with a superresolution at the subwavelength scale, it…
Results from a Princeton-led experiment support a controversial theory that the electron is composed of two particles. A new discovery led by Princeton University could upend our understanding of how electrons behave under extreme conditions in quantum materials. The finding provides experimental evidence that this familiar building block of matter behaves as if it is made of two particles: one particle that gives the electron its negative charge and another that supplies its magnet-like property, known as spin. “We think…
Physicists at ETH Zurich demonstrate that a tiny cloud of atoms can be turned from a heat engine into a cooler by cranking up the interactions between the particles. When a piece of conducting material is heated up at one of its ends, a voltage difference can build up across the sample, which in turn can be converted into a current. This is the so-called Seebeck effect, the cornerstone of thermoelectric effects. In particular, the effect provides a route to…
Smaller, faster, more energy-efficient: future requirements to computing and data storage are hard to fulfill and alternative concepts are continuously explored. Small magnetic textures, so-called skyrmions, may become an ingredient in novel memory and logic devices. In order to be considered for technological application, however, fast and energy-efficient control of these nanometer-sized skyrmions is required. Magnetic skyrmions are particle-like magnetization patches that form as very small swirls in an otherwise uniformly magnetized material. In particular ferromagnetic thin films, skyrmions are…
Lancaster scientists have demonstrated that other physicists’ recent “discovery” of the field effect in superconductors is nothing but hot electrons after all. A team of scientists in the Lancaster Physics Department have found new and compelling evidence that the observation of the field effect in superconducting metals by another group can be explained by a simple mechanism involving the injection of the electrons, without the need for novel physics. Dr Sergey Kafanov, who initiated this experiment, said: “Our results unambiguously…
A novel technique for studying vortices in quantum fluids has been developed by Lancaster physicists. Andrew Guthrie, Sergey Kafanov, Theo Noble, Yuri Pashkin, George Pickett and Viktor Tsepelin, in collaboration with scientists from Moscow State University, used tiny mechanical resonators to detect individual quantum vortices in superfluid helium. Their work is published in the current volume of Nature Communications. This research into quantum turbulence is simpler than turbulence in the real world, which is observed in everyday phenomena such as…
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