Menu

Blog

Archive for the ‘particle physics’ category: Page 42

Jul 9, 2024

Nuclear Decay Detected in the Recoil of a Levitating Bead

Posted by in categories: particle physics, space

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.

Jul 9, 2024

Flexible generation of structured terahertz fields via programmable exchange-biased spintronic emitters

Posted by in category: particle physics

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 ENF(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 ENF 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.

Jul 9, 2024

New shapes of photons open doors to advanced optical technologies

Posted by in categories: particle physics, quantum physics

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 , 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 is most likely found with orbitals too.

Jul 8, 2024

A gold mine for neutrino physics

Posted by in category: particle physics

In 1968, deep underground in the Homestake gold mine in South Dakota, Ray Davis Jr.


At the same time, Steven Weinberg and Abdus Salam were carrying out major construction work on what would become the Standard Model of particle physics, building the Higgs mechanism into Sheldon Glashow’s unification of the electromagnetic and weak interactions. The Standard Model is still bulletproof today, with one proven exception: the nonzero neutrino masses for which Davis’s observations were in hindsight the first experimental evidence.

Today, neutrinos are still one of the most promising windows into physics beyond the Standard Model, with the potential to impact many open questions in fundamental science ( CERN Courier May/June 2024 p29). One of the most ambitious experiments to study them is currently taking shape in the same gold mine as Davis’s experiment more than half a century before.

Continue reading “A gold mine for neutrino physics” »

Jul 8, 2024

Revolutionizing Magnetism: Polarized Light Unlocks Ultrafast Data Storage and Spintronics

Posted by in categories: computing, particle physics

New research introduces a non-thermal method for magnetization using circularly polarized XUV light, which induces significant magnetization changes through the inverse Faraday effect, potentially transforming ultrafast data storage and spintronics.

Intense laser pulses can be used to manipulate or even switch the magnetization orientation of a material on extremely short time scales. Typically, such effects are thermally induced, as the absorbed laser energy heats up the material very rapidly, causing an ultrafast perturbation of the magnetic order.

Scientists from the Max Born Institute (MBI), in collaboration with an international team of researchers, have now demonstrated an effective non-thermal approach of generating large magnetization changes. By exposing a ferrimagnetic iron-gadolinium alloy to circularly polarized pulses of extreme ultraviolet (XUV) radiation, they could reveal a particularly strong magnetic response depending on the handedness of the incoming XUV light burst (left-or right-circular polarization).

Jul 7, 2024

What if absolutely everything is conscious?

Posted by in category: particle physics

Scientists spent ages mocking panpsychism. Now, some are warming to the idea that plants, cells, and even atoms are conscious.

Jul 6, 2024

Stanley Jordan Plays the Periodical Table (Ionization Energies)

Posted by in categories: computing, mobile phones, particle physics, quantum physics

The ionization energy is the amount of energy required to remove a single electron from an atom. If the atom has more than one electron, each one requires more energy than the previous one. The result is a series of increasing energy levels, and in the quantum world these energies correspond to frequencies, as in a musical scale.

This raises an interesting question: if we could hear these frequencies how would they sound? I created an app to find out, and in this video I used my app to share what I learned. As it turns out, the results are quite musical.

Continue reading “Stanley Jordan Plays the Periodical Table (Ionization Energies)” »

Jul 6, 2024

New study shows mysterious solar particle blasts can devastate the ozone layer, bathing Earth in radiation for years

Posted by in category: particle physics

Every few thousand years, the Sun unleashes a burst of high-energy particles that can have serious consequences for life on Earth.

Jul 6, 2024

Scientists Built a Radical Information Engine That Harnesses Molecular Energy

Posted by in category: particle physics

The machine works by manipulating particles in a water bath to generate usable power.

Jul 5, 2024

Exploring the radiative effects of precipitation on Arctic amplification and energy budget

Posted by in categories: climatology, particle physics

One of the key metrics for climate modeling is radiative forcing. Most climate models, including the general circulation models (GCMs), focus on the effects of different atmospheric factors on radiative forcing. However, there are still large uncertainties in satellite observations and multi-model simulations associated with some atmospheric factors.

Among them, clouds are a known source of uncertainty in GCMs, leading to radiative biases. However, another possible source of radiative uncertainty is associated with .

In principle, precipitating particles affect by disrupting incoming shortwave and outgoing longwave radiations. But most conventional GCMs in the Coupled Model Intercomparison Project Phase 6 (CMIP6) treat precipitation diagnostically and exclude the radiative effects of precipitation (REP). Extracting the magnitude of REP in climate models is challenging because of complicated atmosphere-ocean feedback and multi-model variabilities.

Page 42 of 587First3940414243444546Last