Phys.org August 1, 2024 Researchers at UC California developed a pyramid-structured diffractive optical network design (P-D2NN), optimized specifically for unidirectional image magnification and demagnification. The diffractive layers were pyramidally scaled in alignment with the direction of the image magnification or demagnification, to inhibit image formation in the opposite direction, thus achieved the desired unidirectional imaging operation using a much smaller number of diffractive degrees of freedom within the optical processor volume. The design maintained its unidirectional image magnification/demagnification functionality across a large band of illumination wavelengths. It allowed a unidirectional magnifier and a unidirectional demagnifier operation simultaneously in opposite directions, […]
Researchers develop general framework for designing quantum sensors
Phys.org July 30, 2024 Quantum systems of infinite dimension, such as bosonic oscillators, provide vast resources for quantum sensing. A general theory on how to manipulate such bosonic modes for sensing beyond parameter estimation is unknown. A team of researchers in the US (MIT, North Carolina State University) developed a general algorithmic framework, quantum signal processing interferometry (QSPI), for quantum sensing at the fundamental limits of quantum mechanics by generalizing Ramsey-type interferometry. The sensing protocol relied on performing nonlinear polynomial transformations on the oscillator’s quadrature operators by generalizing quantum signal processing (QSP) from qubits to hybrid qubit-oscillator systems. They used […]
Researchers identify useful emission lines in the sun’s outer atmosphere
Phys.org August 2, 2024 When studying the solar spectrum, researchers often search for emission spectra of two iron ions, Fe IX and Fe X, which are useful for studying the sun’s outer atmosphere. However, both spectra contain emission lines that cannot be matched with known electron transitions, limiting the information which can be gathered from them. A team of researchers in the US (Columbia University, Lawrence Livermore National Laboratory, UC Berkeley) presented measurements made in the wavelength range 238–258 Å which helped them to identify the charge state associated with each of the observed lines. This wavelength range was of […]
Stacking molecules like plates improves organic solar device performance
Phys.org August 6, 2024 To further improve the efficiency of optoelectronic devices to convert sun light into electricity, researchers in Japan investigated the relationship between aggregation and Exciton binding energy (Eb) and tetraphenylethylene (TPE). Although theoretical calculations and physical measurements in solution showed no apparent differences between DBC-RD and TPE-RD, the pristine films incorporating these molecules showed significantly different levels of electron affinity, ionization potential, and optical gap. Also, DBC-RD had a smaller Eb value compared with that of TPE-RD. However, these molecules showed similar Eb values under dispersed conditions, suggesting that the decreased Eb of DBC-RD in pristine film […]
Study finds working from home stifles innovation
Phys.org July 30, 2024 After the Covid-19 pandemic firms are now struggling to implement a return to working from the office (WFO), as employees enjoy the significant benefits of working from home (WFH) for their work-life balance. An international team of researchers (USA -University of Chicago, Germany, UK) used unique and detailed data from an Indian IT services firm which contains a precise measure of innovation activity of over 48,000 employees in these three work environments. The key outcomes were the quantity and quality of ideas submitted by employees. Based on an event study design, the quantity of ideas did […]
Synergistic aerogel materials developed for heat and fire insulation
Phys.org August 2, 2024 Researchers in China demonstrated an interpenetrated multinetwork hybrid aerogel realizing thermal insulation, flame retardancy, and high compression modulus. One-dimensional hydroxyapatite nanowires (HAP) formed a three-dimensional interpenetrated multinetwork structure to optimize the thermal conductivity. The multinetwork hybrid aerogels exhibited thermal insulation performance in room temperature and enhanced ultrahigh compression modulus, flame retardancy and self-extinguishing smoke suppression properties. According to the researchers multinetwork hybrid aerogels are promising candidates for efficient heat insulation, fire prevention, and robust applications… read more. TECHNICAL ARTICLE
Top 10 Science and Technology Inventions for the Week of August 2, 2024
01. Method prevents an AI model from being overconfident about wrong answers 02. Twisted carbon nanotubes could achieve significantly better energy storage than advanced lithium-ion batteries 03. When copper becomes transparent: European XFEL creates exotic matter 04. Study: Gases from burning biomass react within clouds, forming secondary organic aerosols 05. An MRI-like tool for quantum materials: Sensor can detect minute magnetic fields at atomic scale 06. New research underscores the close relationship between Saharan dust and hurricane rainfall 07. Researchers trap atoms, force them to serve as photonic transistors 08. Optical fibers fit for the age of quantum computing 09. […]
Ice 0: Researchers discover a new mechanism for ice formation
Phys.org July 26, 2024 The role of the free surface of water in nucleation process remains unclear. Researchers in Japan investigated the microscopic freezing process using molecular dynamics simulations and found that the free surface assisted ice nucleation through an unexpected mechanism. The surface-induced negative pressure enhanced the formation of local structures with a ring topology characteristic of Ice 0-like symmetry, and promoted ice nucleation despite the symmetry differing from ordinary ice crystals. Unlike substrate-induced nucleation via water-solid interactions that occurs directly on the surface, this negative-pressure-induced mechanism promoted ice nucleation slightly inward the surface. Their findings provided a molecular-level […]
Method prevents an AI model from being overconfident about wrong answers
MIT News July 31, 2024 Recent studies have found that common interventions such as instruction tuning often result in poorly calibrated large language models (LLMs). Although calibration is well-explored in traditional applications, calibrating LLMs is uniquely challenging. The challenges stem as much from the severe computational requirements of LLMs as from their versatility, which allows them to be applied to diverse tasks. To address these challenges, researchers at MIT proposed THERMOMETER, a calibration approach tailored to LLMs. For calibrating the LLMTHERMOMETER learned an auxiliary model, using the data given from multiple tasks. According to the researchers it was computationally efficient, […]
‘Miracle’ filter turns store-bought LEDs into spintronic devices
Phys.org July 25, 2024 Current efforts to enable a broader range of optoelectronic functionality are limited because of inherent inefficiencies associated with spin injection across semiconductor interfaces. An international team of researchers (USA – National Renewable Energy Laboratory (NREL), University of Utah, Colorado School of Mines, University of Colorado, France) demonstrated spin injection across chiral halide perovskite/III–V interfaces achieving spin accumulation in a standard semiconductor III–V (AlxGa1−x)0.5In0.5P multiple quantum well light-emitting diode. The spin accumulation was detected through emission of circularly polarized light with a degree of polarization of up to 15 ± 4%. The chiral perovskite/III–V interface characterized with X-ray photoelectron […]