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In a study published in Nature, a research team has, for the first time, observed the antiferromagnetic phase transition within a large-scale quantum simulator of the fermionic Hubbard model (FHM).

This study highlights the advantages of quantum simulation. It marks an important first step towards obtaining the low-temperature phase diagram of the FHM and understanding the role of quantum magnetism in the mechanism of high-temperature superconductivity. The team was led by Prof. Pan Jianwei, Prof. Chen Yuao, and Prof. Yao Xingcan from the University of Science and Technology of China (USTC) of the Chinese Academy of Sciences.

Strongly correlated quantum materials such as high-temperature superconductors are of scientific importance and have potential economic benefits. However, the physical mechanisms underlying these materials remain unclear, posing challenges to their large-scale preparation and application.

A team of experimental physicists led by the University of Cologne have shown that it is possible to create superconducting effects in special materials known for their unique edge-only electrical properties. This discovery provides a new way to explore advanced quantum states that could be crucial for developing stable and efficient quantum computers.

Their study, titled “Induced superconducting correlations in a quantum anomalous Hall insulator,” has been published in Nature Physics.

Superconductivity is a phenomenon where electricity flows without resistance in certain materials. The quantum anomalous Hall effect is another phenomenon that also causes zero resistance, but with a twist: It is confined to the edges rather than spreading throughout.

The Brewster reflectionless effect stands out as one of the simplest yet pivotal discoveries in manipulating waves. Initial investigations were limited to isotropic materials, but later, thanks to the advent of metamaterials, the phenomenon was found to expand into anisotropic materials.

An anomalous Brewster effect has recently been demonstrated in metamaterials, thus increasing the number of degrees of freedom. In materials without magnetic responses, the Brewster effect exclusively applies to transverse–magnetic (TM, or p–wave polarization) waves. Building on the equivalence between TM mode and 2D acoustics, the Brewster effect in acoustics with zero reflection has been demonstrated by utilizing acoustic metamaterials.

In their paper published in the journal Science Bulletin, the researchers first demonstrated this universal theory by matching the continuous boundary conditions and analyzing the relationship between the reflection coefficient and various parameters, proposing a precise method to confirm the near-zero reflection condition. Subsequently, they incorporated intrinsic losses into the permittivity tensors, illustrating a novel method to achieve asymmetric vortex transmission.

While taking snapshots with the high-speed electron camera at the Department of Energy’s SLAC National Acceleratory Laboratory, researchers discovered new behavior in an ultrathin material that offers a promising approach to manipulating light that will be useful for devices that detect, control or emit light, collectively known as optoelectronic devices, and investigating how light is polarized within a material. Optoelectronic devices are used in many technologies that touch our daily lives, including light-emitting diodes (LEDs), optical fibers and medical imaging.

As reported in Nano Letters, the team, led by SLAC and Stanford professor Aaron Lindenberg, found that when oriented in a specific direction and subjected to linear terahertz radiation, an ultrathin film of tungsten ditelluride, which has desirable properties for polarizing light used in optical devices, circularly polarizes the incoming light.

Terahertz radiation lies between the microwave and the infrared regions in the electromagnetic spectrum and enables novel ways of both characterizing and controlling the properties of materials. Scientists would like to figure out a way to harness that light for the development of future optoelectronic devices.

Up to 3% of people with diabetes have an allergic reaction to insulin. A team at Forschungszentrum Jülich has now studied a method that could be used to deliver the active substance into the body in a masked form—in the form of tiny nanoparticles.

The insulin is only released in the target organ when the pH value deviates from the slightly alkaline environment in the blood. The molecular transport system could also serve as a platform for releasing other drugs in the body precisely at the target site.

It’s an old dream in pharmacy: To deliver an active ingredient to the exact place in the body where it is most needed—a cancer drug, for example, directly to the tumor tissue. This minimizes its side effects on other organs and ensures that it has its maximum effect at its target.

Using the High-Altitude Water Cherenkov (HAWC) observatory, an international team of astronomers has observed a very-high energy gamma-ray source designated TeV J2032+4130. Results of the observational campaign, presented July 3 on the preprint server arXiv, provide crucial information regarding the nature of this source.

Sources emitting gamma radiation with photon energies between 100 GeV and 100 TeV are called very-high energy (VHE) gamma-ray sources, while those with photon energies above 0.1 PeV are known as ultra-high energy (UHE) gamma-ray sources. The nature of these sources is still not well understood; therefore, astronomers are constantly searching for new objects of this type to characterize them, which could shed more light on their properties in general.

TeV J2032+4130 was identified in 2005 by the High Energy Gamma Ray Astronomy (HEGRA) experiment as the first VHE gamma-ray source in the TeV range with no lower-energy counterpart. Previous observations of TeV J2032+4130 have revealed that it consists of two sources, namely HAWC J2030+409 and HAWC J2031+415, which is coincident with a pulsar wind nebula (PWN).

Humanoids, robotic or virtual systems with body structures that resemble the human body, have a wide range of real-world applications. As their limbs and bodies mirror those of humans, they could be made to reproduce a wide range of human movements, such as walking, crouching, jumping, swimming and so on.

Computationally generating realistic motions for virtual humanoid characters could have interesting implications for the development of video games, animated films, virtual reality (VR) experiences, and other media content. Yet the environments portrayed in video games and animations are often highly dynamic and complex, which can make planning motions for humanoids introduced in these environments more challenging.

Continue reading “A new model to plan and control the movements of humanoids in 3D environments” »

Researchers at the Artificial Intelligence and Machine Learning Lab (AIML) in the Department of Computer Science at TU Darmstadt and the Hessian Center for Artificial Intelligence (hessian. AI) have developed a method that uses vision language models to filter, evaluate, and suppress specific image content in large datasets or from image generators.

Artificial intelligence (AI) can be used to identify objects in images and videos. This computer vision can also be used to analyze large corpora of visual data.

Researchers led by Felix Friedrich from the AIML have developed a method called LlavaGuard, which can now be used to filter certain image content. This tool uses so-called vision language models (VLMs). In contrast to large language models (LLMs) such as ChatGPT, which can only process text, vision language models are able to process and understand image and text content simultaneously. The work is published on the arXiv preprint server.

To create one-time cures for Alzheimer’s disease, researchers are investigating the application of CRISPR-Cas9 gene-editing for novel therapies. Cutting and pasting genes is difficult with current technology, but CRISPR gene editing may help later stages or those individuals with hereditary mutations. Variants in the lipid transport protein apolipoprotein E (APOE4) have been associated with late-onset Alzheimer’s disease, with a three-to twelve-fold increase in risk.

Researchers engineered the Christchurch gene variation into mice bearing human APOE4 using CRISPR. After that, these mice were crossed, resulting in progeny that carried one or two copies of the modified variation.

The group discovered that mice bearing a single copy of the APOE4-Christchurch variation exhibited a partial defense against Alzheimer’s disease. The disease did not exhibit typical symptoms in mice carrying two copies. The work mimics the advantageous effects of the Christchurch mutation to propose possible treatment strategies for Alzheimer’s disease associated with APOE4.