The study published in Royal Society Open Science presents a groundbreaking approach to understanding the mechanical properties of crystals. Researchers from The University of Osaka have successfully used differential geometry to provide a unified description for the mechanics of crystals and their defects. This breakthrough has significant implications for the development of new materials with enhanced strength and durability.

Crystals, renowned for their beauty and elegance, often appear perfect on the outside. However, upon closer examination, they contain small defects in their structure – missing atoms or extra bonds. These imperfections have important mechanical consequences, as they can serve as starting points for fractures or even be used to strengthen materials. Understanding defects and their phenomena is crucial for researchers.

The study’s lead author, Shunsuke Kobayashi, notes that “defects come in many forms.” For instance, there are dislocations associated with the breaking of translational symmetry and disclinations associated with the breaking of rotational symmetry. Capturing all these types of defects within a single mathematical theory is not straightforward.

Previous models have struggled to reconcile the differences between dislocations and disclinations, indicating that modifications to the theory are needed. The research team found that new mathematical tools using differential geometry proved to be exactly what was required to address these issues.

Differential geometry provides an elegant framework for describing these complex phenomena. Simple mathematical operations can capture these effects, allowing researchers to focus on the similarities between seemingly disparate defects. Using the formalism of Riemann-Cartan manifolds, the team elegantly encapsulated the topological properties of defects and rigorously proved the relationship between dislocations and disclinations.

In addition, they derived analytical expressions for the stress fields caused by these defects. The research team hopes that their geometric approach to describing the mechanics of crystals will eventually inspire scientists and engineers to design materials with specific properties by taking advantage of defects, such as the strengthening of materials seen with disclinations. This breakthrough is yet another example of how beauty in mathematics can help us understand beauty in nature.

Imagine a world where technology could reveal hidden secrets just like magic. Scientists have made a breakthrough in creating artificial optical structures called metasurfaces that can control the way they interact with polarized light. This innovation has potential applications in data encryption, biosensing, and quantum technologies.

The team from the Bionanophotonic Systems Laboratory at EPFL’s School of Engineering collaborated with researchers in Australia to create a “chiral design toolkit” that is elegantly simple yet powerful. By varying the orientation of tiny elements called meta-atoms within a 2D lattice, scientists can control the resulting metasurface’s interaction with polarized light.

The innovation was showcased by encoding two different images on a metasurface optimized for the invisible mid-infrared range of the electromagnetic spectrum. The first image of an Australian cockatoo was encoded in the size of the meta-atoms, which represented pixels, and could be decoded with unpolarized light. The second image of the Swiss Matterhorn was encoded using the orientation of the meta-atoms, so that when exposed to circularly polarized light, the metasurface revealed a picture of the iconic mountain.

“This experiment showcased our technique’s ability to produce a dual layer ‘watermark’ invisible to the human eye, paving the way for advanced anticounterfeiting, camouflage and security applications,” says Ivan Sinev, researcher at the Bionanophotonics Systems Lab.

Beyond encryption, the team’s approach has potential applications in quantum technologies, where polarized light is used to perform computations. The ability to map chiral responses across large surfaces could also streamline biosensing.

“We can use chiral metastructures like ours to sense, for example, drug composition or purity from small-volume samples. Nature is chiral, and the ability to distinguish between left- and right-handed molecules is essential, as it could make the difference between a medicine and a toxin,” says Felix Richter, researcher at the Bionanophotonic Systems Lab.

This breakthrough has opened doors to new possibilities in data encryption, biosensing, and quantum technologies. The future of technology is indeed bright, and twisted light just got a whole lot more interesting.

The discovery of a life-saving molecule whose twin is a deadly poison might seem like science fiction, but it’s a harsh reality known as “chirality.” This phenomenon occurs when two molecules have the same composition yet differ in shape and arrangement in space, much like our right and left hands. Understanding and controlling chirality is crucial for designing effective drugs.

A team from the University of Geneva (UNIGE), collaborating with the University of Pisa, has made a groundbreaking discovery in developing a new family of remarkably stable chiral molecules. This breakthrough opens up new prospects for geometry-controlled drug design and is published in the Journal of the American Chemical Society.

The concept of chirality arises when a molecule cannot be superimposed on its mirror image through any combination of rotations, translations, or geometric changes. This universal molecular asymmetry requires chemists to create chiral molecules that interact precisely with living systems.

In this context, researchers have developed a novel type of stereogenic center, where the central carbon atom is surrounded by oxygen and nitrogen atoms rather than carbon chains. This innovative design has led to the creation of stable chiral molecules whose switch from one form to its mirror sister is highly unlikely, making them suitable for safe storage without specific conditions.

The exceptional stability of these new molecular structures was demonstrated through dynamic chromatography techniques and quantum chemistry calculations. For example, it would take an estimated 84,000 years at room temperature for half a sample of the first molecule developed to transform into its mirror molecule. This remarkable stability guarantees secure storage and reduces the risk of accidental switching from a drug to an inactive or even toxic molecule.

This breakthrough in drug design and material creation has significant implications, offering new possibilities for the development of stable, controlled three-dimensional chiral molecules. As Professor Gennaro Pescitelli from the University of Pisa notes, these novel stereogenic centers provide a fresh way of organizing molecular space, opening up a whole new degree of freedom and imagination in chemical synthesis.

This discovery has far-reaching consequences for the pharmaceutical industry and material science, highlighting the importance of continued research in understanding and controlling chirality to design effective drugs and innovative materials.