Phys.org October 18, 2023 Researchers in New Zealand used a small glass bulb containing an atomic vapor to demonstrate a new form of antenna for radio waves. The bulb was “wired up” with laser beams and could therefore be placed far from any receiver electronics. They combined a rubidium vapor cell with a corner-cube prism reflector to form a passive RF transducer, allowing the detection of microwave signals at a location distant from the active components required for atomic sensing. The transducer had no electrical components and was optically linked to an active base station by a pair of free-space […]
Researchers test seafloor fiber optic cable as an earthquake early warning system
Science Daily October 17, 2023 An international team of researchers (USA – Caltech, industry, Chile) provided a real‐data test for offshore earthquake early warning (EEW) with distributed acoustic sensing (DAS) by transforming submarine fiber‐optic cable into a dense seismic array. They constrained earthquake locations using the arrival‐time information recorded by the DAS array and earthquake magnitudes were estimated directly from strain rate amplitudes by applying a scaling relation transferred from onshore DAS arrays. According to the researchers their results indicate that using this single 50 km offshore DAS array can offer ∼3 s improvement in the alert time of EEW […]
Solving quantum mysteries: New insights into 2D semiconductor physics
Nanowerk October 16, 2023 An international team of researchers (Australia, Spain) has introduced a novel approach ‘quantum virial expansion,’ to uncover the complex quantum interactions in two-dimensional semiconductors. They showed that this constituted a perturbatively exact theory in the high-temperature or low-doping regime, where the electrons’ thermal wavelength was smaller than their interparticle spacing. They obtained exact analytic expressions for the photoluminescence and predicted new features such as a nontrivial shape of the attractive branch peak related to universal resonant exciton-electron scattering and an associated energy shift from the trion energy. The theory allowed them to formally unify the two […]
Study hints at new way to improve on spintronics for future tech
Nanowerk October 13, 2023 An international team of researchers (USA- Ohio State University, Sweden, UK) used a new method involving the reflection of polarized light on thin films of light metal chromium, successfully detected the orbital Hall effect. The orbital polarization was in-plane, transverse to the current direction, and scaled linearly with current density, consistent with the orbital Hall effect. Comparing the thickness-dependent magneto-optical measurements with ab initio calculations, they estimated an orbital diffusion length in Cr of 6.6±0.6nm. The potential application of this discovery in spintronics could lead to improve data storage in the next generation of computer devices […]
Superlensing without a super lens: Physicists boost microscopes beyond limits
Phys.org October 18, 2023 Imaging with resolutions much below the wavelength λ remains challenging at lower frequencies, where exponentially decaying evanescent waves are generally measured using a tip or antenna close to an object. Such approaches are often problematic because probes can perturb the near-field itself. Researchers in Australia have demonstrated that information encoded in evanescent waves can be probed further than previously thought, by reconstructing truthful images of the near-field through selective amplification of evanescent waves like a virtual superlens that images the near field without perturbing it. They quantified trade-offs between noise and measurement distance, experimentally demonstrated reconstruction […]
Time Travel Simulations Can Solve Impossible Problems, Physicists Say
Science Alert October 13, 2023 Although the existence of closed time like curves is hypothetical, they can be simulated probabilistically by quantum-teleportation circuits. An international team of researchers (UK, Switzerland, USA – NIST, University of Maryland) leveraged simulations to pinpoint a counterintuitive nonclassical advantage achievable with entanglement. A metrologist prepared probes to input into an unknown quantum interaction. The goal was to infer as much information per probe as possible. If the input was optimal, the information gained per probe could exceed any value achievable classically. The problem was that, only after the interaction the metrologist could learn which input […]
Tiny memory cell withstands extreme temperatures
Nanowerk October 16, 2023 Analog switching in ferroelectric devices promises neuromorphic computing with the highest energy efficiency if limited device scalability can be overcome. Researchers in Germany demonstrated the ferroelectric switching characteristics of sub-5 nm thin Al0.74Sc0.26N films grown on Pt/Ti/SiO2/Si and epitaxial Pt/GaN/sapphire templates by sputter-deposition. They focused on the following major achievements compared to previously available wurtzite-type ferroelectrics: 1) Record low switching voltages down to 1 V are achieved, which was in a range that could be supplied by standard on-chip voltage sources. 2) Compared to the previously investigated deposition of ultrathin Al1−xScxN films on epitaxial templates, a […]
Widely tunable terahertz lasers boost photo-induced superconductivity in K₃C₆₀
Phys.org October 12, 2023 Photoexcitation at terahertz and mid-infrared frequencies has emerged as an effective way to manipulate functionalities in quantum materials, in some cases creating non-equilibrium phases that have no equilibrium analogue. In K3C60, a metastable zero-resistance phase was observed that has optical properties, nonlinear electrical transport, and pressure dependencies compatible with non-equilibrium high-temperature superconductivity. An international team of researchers (Germany, Switzerland, Italy, UK) demonstrated a two-orders-of-magnitude increase in photo-susceptibility near 10 THz excitation frequency. At these drive frequencies, a metastable superconducting-like phase was observed up to room temperature. The discovery of a dominant frequency scale sheds light on the […]
Top 10 Science and Technology Inventions for the Week of October 13, 2023
01. New easy-to-use optical chip can self-configure to perform various functions 02. Discovery may enable network interface for quantum computers 03. Free-space nanoprinting beyond optical limits to create 4D functional structures 04. Generating circularly polarised light 05. Illuminating errors creates a new paradigm for quantum computing 06. Nanoscale rust: The future of magnets? 07. Scientists discover ‘flipping’ layers in heterostructures to cause changes in their properties 08. Creating a broadband diffractive graphene orbital angular momentum metalens by laser nanoprinting 09. Research shows how topology can help create magnetism at higher temperatures 10. Scientists demonstrate electrically tunable microlens array using simple […]