Phys.org September 19, 2024 The roles of Arctic aerosols as ice-nucleating particles are crucial for assessing the climate sensitivity of Arctic mixed-phase clouds and predicting their response to Arctic warming. An international team of researchers (Japan, Norway) presented a full-year record of ice-nucleating particle concentrations over Svalbard, where surface warming has been anomalously faster than the Arctic average. While the variation of ice-nucleating particles active at around −30 °C was relatively small, those active at higher temperatures tended to increase exponentially with rising surface air temperatures when the surface air temperatures rose above 0 °C and snow/ice-free barren and vegetated areas appeared […]
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Geophysicist’s method could give months’ warning of major earthquakes
Phys.org August 30, 2024 Earthquake precursors are ambiguous, but recent experimental studies suggest that robust warning signs may precede large seismic events in the short (day-to-months) term. An international team of researchers (USA – University of Alaska Fairbanks, Germany) showed that Ridgecrest sequence (California) and Anchorage earthquake (Alaska) were preceded by up to ~3 months of tectonic unrest on regional scales, as evidenced by abnormal low-magnitude seismicity spreading over the ~15-25% of Southern California and Southcentral Alaska. This precursory unrest had been discovered with an algorithm that integrates an innovative random forest machine learning approach and statistical features built from […]
Photon-like electrons in a four-dimensional world discovered in a real material
Phys.org March 14, 2024 Because of their differences from standard electrons, Dirac electrons are expected to add unprecedented electronic properties to materials. Researchers in Japan discovered a method enabling selective observation of the Dirac electrons in materials. Using electron spin resonance, to directly observe unpaired electrons in materials to distinguish differences in character, they established a method to determine their scope of action in the materials and their energies. They showed that electron spin resonance revealed that α-ET2I3 (ET = bis(ethylenedithio)-tetrathiafulvalene) at 1 bar contained a nearly three-dimensional DFs above ∼100 K coexisting with standard fermions. The close charge-transfer ET–I3 […]
Powering the quantum revolution: Quantum engines on the horizon
Phys.org September 27, 2023 Quantum theory offers genuine non-classical forms of energy, different from heat, which so far have not been exploited in cyclic engines. An international team of researchers (Germany. Japan, Argentina) experimentally realized a quantum many-body engine fueled by the energy difference between fermionic and bosonic ensembles of ultracold particles that follows from the Pauli exclusion principle. They employed a harmonically trapped superfluid gas of 6Li atoms close to a magnetic Feshbach resonance that allowed them to effectively change the quantum statistics from Bose–Einstein to Fermi–Dirac, by tuning the gas between a Bose–Einstein condensate of bosonic molecules and […]
Optical memristors review: Shining a light on neuromorphic computing
Phys.org June 5, 2023 In recent years, the ability to vary the conductance of a channel in electronics has enabled in-memory computing, thus leading to substantial interest in memristors. An international team of researchers (USA – University of Pittsburg, University of Maryland, Germany, UK) reviewed recent progress in this important and emerging aspect of photonic integrated circuits and provided an overview of the current state of the art. They shed light on the evolution of this technology—and the work that still needs to be done for it to reach its full potential. They have provided a comprehensive overview of recent […]
Wafer-scale nanofabrication of telecom single-photon emitters in silicon
Phys.org February 23, 2023 Monolithic integration of single-photon sources in a controllable way would give a resource-efficient route to implement millions of photonic qubits in photon integrated circuits. To run quantum computation protocols, these photons must be indistinguishable. Building on their previous work researchers in Germany have shown how focused ion beams from liquid metal alloy ion sources are used to place single-photon emitters at desired positions on the wafer while obtaining a high creation yield and high spectral quality. After several cooling-down and warming-up cycles, there was no degradation of their optical properties. To allow for wafer-scale engineering of […]
New method can improve explosion detection
Science Daily July 22, 2022 Explosions produce infrasound waves capable of propagating globally, but the spatio-temporal variability of the atmosphere makes detecting events difficult. Machine learning (ML) is well-suited to identify the subtle and nonlinear patterns in explosion infrasound signals, but a previous lack of ground-truth data inhibited training of generalized models. A team of researchers in the US (University of Alaska, Air Force, University of Mississippi, Los Alamos National Laboratory) has developed a physics-based method that propagates infrasound sources through realistic atmospheres to create 28,000 synthetic events, which are used to train ML classifiers. A simple artificial neural network […]
Magnetic spins that ‘freeze’ when heated: Nature in the wrong direction
Nanowerk July 4, 2022 An international team of researchers (the Netherlands, Sweden) observed an unusual magnetic transition in elemental neodymium where, with increasing temperature, long-range multiply periodic ‘multi-Q’ magnetic order emerged from a self-induced spin glass. They characterized the local order of a previously reported spin glass phase and quantified the emergence of long-range multi-Q order with increasing temperature. Using the analysis tools they developed, they determined the glass transition temperature from measurements of the spatially dependent magnetization. They compared these observations with atomistic spin dynamics simulations to reproduce the qualitative observation of a phase transition from a low-temperature spin […]
Researchers develop silicon cuboid nanoantenna
Phys.org March 21, 2022 The Purcell effect is commonly used to increase the spontaneous emission rate by modifying the local environment of a light emitter. Researchers in China studied the scattering cross section, polarization charge distribution, and electromagnetic field distribution for electromagnetic plane wave illuminating the silicon dielectric cuboid nanoantenna and identified simultaneous existence of electric dipole (ED), magnetic dipole (MD) and electric quadrupole (EQ) emission resonance modes in this nanoantenna. When they calculated the Purcell factor of ED, MD, and EQ emitters with different moment orientations as a function of radiation wavelength by placing these point radiation source within […]
This 500-Year-Old Landslide Found in The Red Sea Could Trigger a Future Tsunami
Science Alert February 28, 2022 Tsunamigenic submarine landslides are common in deep, steep-sided, and seismically active basins of the Red Sea. Because the rift is narrow, tsunami formed on one margin dissipate little before impacting the opposite side. An international team of researchers (USA – University of Miami, UC Santa Cruz, industry, Columbia University, Italy, Saudi Arabia) examined the tsunamigenic potential of an incipient landslide in the Tiran Straits that started, but then stopped after a short distance. Their analyses fix the age of this landslide to within the last 500 years. Tsunami modeling predicts ∼10 m wave heights on […]