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Scientists have detected the decay of radioactive nuclei by tracking the recoil of dust-sized spheres on which the nuclei were embedded.

Scientists have developed a new way to trap small particles with light. Building on the Nobel Prize winning technique of optical tweezers (Arthur Ashkin, 2018), a team of physicists, led by Dr. David Phillips at the University of Exeter, has advanced the possibilities of optical trapping.

The research paper, published in the journal Science Advances, is titled “Photon-efficient optical tweezers via wavefront shaping.”

Conventional optical tweezers, developed in the 1980s, are a tightly focused laser beam which can attract and trap certain micro-sized particles or organisms, akin to grabbing something with a pair of tweezers.

A levitating microparticle is observed to recoil when a nucleus embedded in the particle decays—opening the door to future searches of invisible decay products.

For centuries, physicists have exploited momentum conservation as a powerful means to analyze dynamical processes, from billiard-ball collisions to galaxy formation to subatomic particle creation in accelerators. David Moore and his research team at Yale University have now put this approach to work in a new setting: they used momentum conservation to determine when a radioactive atom emitted a single helium nucleus, known as an alpha particle (Fig. 1) [1]. The demonstration suggests that—with further improvements—researchers might be able to use this technique to detect other nuclear-decay products, such as neutrinos and hypothetical dark-matter particles (see also Special Feature: Sensing a Nuclear Kick on a Speck of Dust).

The basic idea is simple: if the radioactive atom is embedded in a larger object, then an outgoing decay product will exert a backreaction on that object, causing it to recoil in the opposite direction. But is it really possible to detect the recoil kick from a particle as small as a helium nucleus? The answer lies in how precisely we can measure the larger object’s momentum. One of the main limitations is friction: if the larger object is slowed down by frictional forces, then its motion won’t reflect the impulse from the decaying particle.

In this work, we show that the flexible programming of the exchange-biased magnetic heterostructure enables the direct generation of various structured terahertz beams with complex polarization distributions. In the above demonstrations, we did not perform amplitude design on E_NF(r), as lasers with Gaussian profiles were utilized to excite various programmed emitters. To exert control over local NF amplitudes, spatial light modulators can be further employed to manipulate the amplitude profiles of excitation lasers.

It is important to acknowledge that, owing to the inherent capability of generating only linearly polarized E_NF locally, a crucial constraint arises: the NF terahertz amplitudes for the LCP and RCP components must be equal at all locations, leading to \({A}_{NF}^{L}(\mathbf{r})={A}_{NF}^{R}(\mathbf{r})\) at the emitter’s surface. As a consequence, both LCP and RCP terahertz fields are simultaneously generated in the far field. In situations where terahertz beams with a pure polarization state are of interest, one can strategically design the magnetization pattern so that desired polarization state is focused at the center, while surrounding it with other polarizations. By employing simple spatial filtering, this pure polarization state can be isolated and utilized. This concept was demonstrated by the LCP Gaussian beam in the last demonstration, where different spatial phase gradients were applied on the LCP and RCP light beams, allowing for their spatial separation in the far field.

Furthermore, by fabricating the heterostructures into appropriately oriented micro-structures, one can induce confinements onto the local charge currents [38,39,40]. This enables independent control over the x- and y-components of the local terahertz fields, potentially facilitating the realization of an arbitrary terahertz wave generator.

Researchers from the University of Twente in the Netherlands have gained important insights into photons, the elementary particles that make up light. They ‘behave’ in an amazingly greater variety than electrons surrounding atoms, while also being much easier to control.

These new insights have broad applications from smart LED lighting to new photonic bits of information controlled with quantum circuits, to sensitive nanosensors. Their results are published in Physical Review B.

In atoms, minuscule elementary particles called electrons occupy regions around the nucleus in shapes called orbitals. These orbitals give the probability of finding an electron in a particular region of space. Quantum mechanics determines the shape and energy of these orbitals. Similarly to electrons, researchers describe the region of space where a photon is most likely found with orbitals too.

Headworn tech from a University of Michigan startup could protect agricultural and industrial workers from airborne pathogens.

Taza Aya has created a hard hat with an air curtain that prevents nearly all aerosols from reaching the face, using nonthermal plasma to ensure air purity. Proven effective in tests, this innovative device is designed for industries needing strong respiratory protection and will be available by 2025.

Continue reading “Invisible Shield: Wearable Air Curtain Blocks 99.8% of Aerosol Viruses” »

Researchers from Tel Aviv University (TAU) have created a new type of glass with unique and even contradictory properties, such as being a strong adhesive (sticky) and incredibly transparent at the same time. The glass, which forms spontaneously when comes in contact with water at room temperature, could bring about a revolution in an array of different and diverse industries such as optics and electro-optics, satellite communication, remote sensing and biomedicine.

The glass was discovered by a team of researchers from Israel and the world, led by PhD student Gal Finkelstein-Zuta and Prof. Ehud Gazit from the Shmunis School of Biomedicine and Cancer Research at the Faculty of Life Sciences and the Department of Materials Science and Engineering at the Faculty of Engineering at TAU. The results of the research were recently published in the prestigious scientific journal Nature.

High temperatures continued to break records in June.

El mes de junio fue el sexto mes del año más caluroso registrado en la historia y el decimotercer mes consecutivo en establecer un récord de temperatura mensual, informó este lunes la Organización Meteorológica Mundial (OMM).

Los datos del Servicio de Cambio Climático Copernicus de la Unión Europea revelaron que la temperatura global promedio ha estado 1,5°C por encima del nivel preindustrial durante doce meses consecutivos, pese a que ese aumento marca la meta del Acuerdo de París para fin de siglo.

Continue reading “Las altas temperaturas siguieron rompiendo récord en junio” »

Vending machines are an old charming piece of technology that supposedly makes the lives of people easier by making water, snacks and food in general readily available.

American Rounds says that it aims to redefine convenience in ammunition purchasing, as its ammo dispensers can be accessed round the clock.

Continue reading “Ammo ATM? AI-powered bullet vending machines introduced in US” »