Phys.org July 8, 2024 Large-scale and high-dimensional permutation operations are important for various applications in telecommunications and encryption. Researchers at UCLA, California, used all-optical diffractive computing to execute a set of high-dimensional permutation operations between an input and output field-of-view through layer rotations in a diffractive optical network. In this design every diffractive layer had four orientations: 0 deg, 90 deg, 180 deg and 270 deg. Each unique combination of these layers represented a distinct rotation state, tailored for a specific permutation operation. A K-layer rotatable diffractive design could perform up to independent permutation operations. The original input information could […]
The forbidden propagation of hyperbolic phonon polaritons and applications in near-field energy transport
Phys.org July 8, 2024 GHz burst-mode femtosecond (fs) laser provides distinct characteristics in materials processing as compared with the conventional irradiation scheme of fs laser (single-pulse mode). Researchers in Japan used the moderate pulse interval of 205 ps in the burst pulse for high-quality and high-efficiency micromachining of single crystalline sapphire by laser induced plasma assisted ablation (LIPAA). The preceding pulses in the burst generated plasma by ablation of copper placed behind the sapphire substrate, which interacted with the subsequent pulses to induce ablation at the rear surface of sapphire substrates. The ablation quality, efficiency, and the fabrication resolution were […]
High-speed electron camera uncovers new ‘light-twisting’ behavior in ultrathin material
Phys.org July 10, 2024 Manipulating the polarization of light at the nanoscale is key to the development of next-generation optoelectronic devices. This is typically done via waveplates using optically anisotropic crystals, with thicknesses on the order of the wavelength. A team of researchers in the US (Stanford, SLAC Nation Acceleration Laboratory, Harvard University, Columbia University, Florida State University, UCLA) used a novel ultrafast electron-beam-based technique sensitive to transient near fields at THz frequencies to observe a giant anisotropy in the linear optical response in Tungsten ditelluride (WTe2). They demonstrated that it is possible to tune THz polarization using a 50 […]
Improving safety of AI research for engineering biology
Phys.org July 8, 2024 The development of high-throughput methods like massively parallel reporter assays, data-rich microscopy techniques, computational protein structure prediction and design, and the development of whole-cell models are able to generate huge volumes of data. An international team of researchers (UK, USA – University of Washington) presented a community-developed framework for assessing hazards posed by using data-centric methods to engineer biology and demonstrated its application to two synthetic biology case studies. They showed the diversity of considerations that arise in common types of bioengineering projects and provided some guidelines and mitigating steps. According to the researchers understanding potential […]
Moving from the visible to the infrared: Developing high quality nanocrystals
Phys.org July 9, 2024 Colloidal semiconductor nanocrystals based on CdSe have been precisely optimized for photonic applications in the visible spectrum. A team of researchers in the US (University of Illinois Urbana-Champaign, Carle Illinois College of Medicine, Urbana) developed homogeneous nanocrystals with tunable bandgaps in the infrared spectrum based on HgSe and HgxCd1−xSe alloys derived from CdSe precursors. They found that Ag+ catalyses cation interdiffusion reduced the CdSe–HgSe alloying temperature from 250 °C to 80 °C. Together with ligands that modulated surface cation exchange rates, interdiffusion-enhanced Hg2+ exchange of diverse CdSe nanocrystals proceeded homogeneously and completely. The products retained the size, shape […]
A new metamaterial concept offering the potential for more efficient data storage
Nanowerk July 16, 2024 Researchers in Germany demonstrated that not just individual bits, but entire bit sequences can be stored in cylindrical domains. They used high perpendicular magnetic anisotropy synthetic antiferromagnets in the form of multilayer-based metamaterials whose antiferromagnetic interlayer exchanged energy was purposefully reduced below the out-of-plane demagnetization energy controlling magnetic domain formation. They demonstrated via macroscopic magnetometry and microscopic Lorentz transmission electron microscopy, that it was possible to stabilize nanometer-scale stripe and bubble textures consisting of ferromagnetic out-of-plane domain cores separated by antiferromagnetic in-plane Bloch-type domain walls. According to the researchers this coexistence of mixed ferromagnetic/antiferromagnetic order on […]
New method achieves tenfold increase in quantum coherence time via destructive interference of correlated noise
Phys.org July 10, 2024 Decoherence and imperfect control are crucial challenges for quantum technologies. Common protection strategies rely on noise temporal autocorrelation, which is not optimal if other correlations are present. An international team of researchers (Israel, Germany, USA – Caltech, industry) developed and experimentally demonstrated a strategy that used the cross-correlation of two noise sources. Utilizing destructive interference of cross-correlated noise extended the coherence time tenfold, improved control fidelity, and surpassed the state-of-the-art sensitivity for high frequency quantum sensing, significantly expanding the applicability of noise protection strategies… read more. Open Access TECHNICAL ARTICLE
Researchers discover a new form of scientific fraud: Uncovering ‘sneaked references’
Phys.org July 10, 2024 When researchers write a scholarly article, they must cite the work of peers to provide context, detail sources of inspiration and explain differences in approaches and results. A positive citation by other researchers is a key measure of visibility for a researcher’s own work. An international team of researchers (Sweden, France, Kazakhstan) reported evidence of an undocumented method to manipulate citation counts involving “sneaked” references. Sneaked references are registered as metadata for published scientific articles in which they do not appear. This manipulation exploits trusted relationships between publishers, the Crossref metadata registration agency, digital libraries, and […]
Scientists call for ‘major initiative’ to study whether geoengineering should be used on glaciers
Phys.org July 11, 2024 According to an international team of researchers (USA – University of Chicago, NASA Goddard Institute, MIT, Carnegie Mellon University, Germany, Finland) earth’s two large ice sheets, in Antarctica and Greenland are the major contributor to sea-level rise and the subsequent damage to natural and human systems. They are currently deteriorating and will continue to deteriorate even under the most optimistic greenhouse-gas emissions scenarios. Although they cannot be stopped, it may be possible to slow the deterioration. Over the last four decades, scientific research on ice-sheet deterioration and sea-level rise has been focused on two essential questions: […]
Scientists develop new AI method to create material ‘fingerprints’
Phys.org July 16, 2024 Understanding and interpreting dynamics of functional materials in situ is a challenge in physics and materials science due to the difficulty of experimentally probing materials at varied length and time scales. Although X-ray photon correlation spectroscopy (XPCS) is uniquely well-suited, spatial and temporal heterogeneity in material behavior can make interpretation of experimental XPCS data difficult. A team of engineers in the US (Argonne National Laboratory, University of Chicago) developed an unsupervised deep learning (DL) framework for automated classification of relaxation dynamics from experimental data without requiring any prior physical knowledge of the system. They demonstrated how […]