Phys.org June 11, 2024 Brittle deformation models commonly rely on Mohr-Coulomb plasticity coupled with prescribed softening of cohesion and/or friction with accumulated plastic strain. This captures fundamental properties of brittle failure, but is overly sensitive to empirical softening parameters that cannot be determined experimentally. Researchers in France designed a brittle constitutive law that captured key processes of brittle deformation, and could be straightforwardly implemented in standard geodynamic models. In the Sub-Critically-Altered Maxwell (SCAM) flow law the damage progressively and permanently weakened the rock’s elastic moduli, until cracks catastrophically interact and coalesce up to macroscopic failure. The model’s micromechanical parameters could […]
A ‘liquid battery’ advance—strategies for electrocatalytic hydrogenation
Phys.org June 12, 2024 The selective electrocatalytic hydrogenation of organics with transition metal hydrides is a promising strategy for electrosynthesis and energy storage. Researchers at Stanford University reported the electrocatalytic hydrogenation of acetone with a cyclopentadienone-iridium complex in a tandem electrocatalytic cycle with a cobaltocene mediator. The reductive protonation of cobaltocenium with mild acids generated (C5H5)CoI(C5H6) (CpCoI(CpH)), which functioned as an electrocatalytic hydride mediator to deliver a hydride to cationic Ir(III) without generating hydrogen. Electrocatalytic hydride transfer by CpCoI(CpH) to a cationic Ir species led to the efficient electrohydrogenation of acetone. According to the researchers hydride–transfer mediation presents a powerful […]
New method could allow multi-robot teams to autonomously and reliably explore other planets
Phys.org June 9, 2024 Researchers in the UK proposed a novel methodology for trustworthy autonomous multi-robot teams which incorporates data from multiple sources (HiRISE orbiter imaging, probability distribution maps, and on-board rover sensors) to find efficient exploration routes in Jezero crater. A map was generated, consisting of a 3D terrain model, traversability analysis, and probability distribution map of points of scientific interest. A three-stage mission planner generated an efficient route, which maximized the accumulated probability of identifying points of interest. A 4D RRT* algorithm was used to determine smooth, flat paths, and prioritized planning was used to coordinate a safe […]
New method optimizes lithium extraction from seawater and groundwater
Phys.org June 8, 2024 Understanding how particle features influence Li and sodium (Na) co-intercalation is crucial for system design and enhancing Li selectivity. A team of researchers in the US (University of Chicago, Illinois Institute of Technology, Argonne National Laboratory, University of New York at Buffalo) investigated a series of FePO4 particles with various features and revealed the importance of harnessing kinetic and chemo-mechanical barrier difference between lithiation and sodiation to promote selectivity. The thermodynamic preference of FePO4 provided baseline of selectivity while the particle features were critical to induce different kinetic pathways and barriers, resulting in different Li to […]
New theory describes how waves carry information from surroundings
Phys.org June 12, 2024 Using waves to explore our environment is a widely used paradigm, ranging from seismology to radar technology, and from biomedical imaging to precision measurements. The central aim is to gather as much information as possible about an object of interest by sending a probing wave at it and processing the information delivered back to a detector. An international team of researchers (Austria, France) demonstrated that an electromagnetic wave scattered at an object carries locally defined and conserved information about all of the object’s constitutive parameters. They introduced the density and flux of Fisher information for general […]
Nonreciprocal quantum batteries exhibit remarkable capacities and efficiency
Phys.org June 8, 2024 Nonreciprocity enables directional flow of signals and efficient noise suppression, constituting a key element in the architecture of current quantum information and computing systems. An international team of researchers (Poland, Canada) introduced nonreciprocity through reservoir engineering during the charging process resulting in a fourfold increase in battery energy compared to conventional charger-battery systems. This effect was observed in the stationary limit and remained applicable even in overdamped coupling regimes, eliminating the need for precise temporal control over evolution parameters. The result could be extended to a chiral network of quantum nodes, serving as a multicell quantum […]
Pseudomagic quantum states: A path to quantum supremacy
Phys.org June 11, 2024 An international team of researchers (USA – Harvard University, MIT, University of Chicago, Germany) introduced “pseudomagic” ensembles of quantum states that are computationally indistinguishable from those with high nonstabilizerness. They demonstrated that pseudomagic neither follows from pseudoentanglement nor implies it. It offers fresh insights into the theory of quantum scrambling: it uncovers states that, even though they originated from nonscrambling unitaries, remain indistinguishable from scrambled states to any physical observer. Applications include new lower bounds on state synthesis problems, property testing protocols, and implications for quantum cryptography. According to the researchers only quantities measurable by a […]
‘Quantum optical antennas’ provide more powerful measurements on the atomic level
Science Daily June 10, 2024 A resonantly excited atomic optical dipole simultaneously generates propagating (far) and evanescent (near) electromagnetic fields. The near-field component diverges in the limit of decreasing distance, indicating an optical antenna with the potential for enormous near-field intensity enhancement. In principle, any atomic optical dipole in a solid can serve as an optical antenna; however, most of them suffer from environmentally induced decoherence that largely mitigates field enhancement. An international team of researchers (USA – University of Chicago, Argonne National Laboratory, Spain) demonstrated that germanium vacancy centres in diamond are exemplary antennas. They measured up to million-fold […]
Researchers demonstrate new way to ‘squeeze’ infrared light
Science Daily June 10, 2024 Recent theoretical studies have suggested that transition metal perovskite oxide membranes can enable surface phonon polaritons in the infrared range with low loss and much stronger subwavelength confinement than bulk crystals. Such modes, however, have not been experimentally observed so far. An international team of researchers (USA – North Carolina State University, Lawrence Berkeley National Laboratory, Stanford University, SLAC National Accelerator Laboratory, Switzerland) studied the phonon polaritons in a 100 nm thick freestanding crystalline membrane of SrTiO3 transferred on metallic and dielectric substrates. They observed a symmetric-antisymmetric mode splitting which gave rise to epsilon-near-zero and Berreman […]
Scientists create world’s strongest iron-based superconducting magnet using AI
Phys.org June 7, 2024 Iron-based high-temperature (high-Tc) superconductors have good potential to serve as materials in next-generation superstrength quasipermanent magnets owing to their distinctive topological and superconducting properties. However, their unconventional high-Tc superconductivity paradoxically associates with anisotropic pairing and short coherence lengths, causing challenges by inhibiting supercurrent transport at grain boundaries in polycrystalline materials. An international team of researchers (Japan, UK) manipulated intricate polycrystalline microstructures resulting in a bulk Ba0.6K0.4Fe2As2 permanent magnet with a magnetic field that was 2.7 times stronger than previously reported. They demonstrated magnetic field stability for a practical 1.5 T permanent magnet, which is a vital aspect […]