Topology, a fascinating branch of mathematics, explores the properties of figures or objects that remain unchanged under continuous deformations—those that do not involve cutting or sewing the object. Consider the everyday example of shoelaces: tying a knot involves passing one end under the other to create a more secure structure. If the ends were glued together, the knot would stay locked within the lace, and the only way to untie it would be to cut it. This concept of topology is crucial not only for understanding abstract mathematical objects, like the very definition of a “knot,” but it also has significant applications in various fields. These range from theoretical physics (including field theories and Feynman path integrals) to the statistical mechanics of soft matter (like polymers, liquid crystals, and other complex fluids), and even to essential biological molecules such as DNA, RNA, and proteins. Due to the vast and specialized nature of these fields, a common language to integrate their shared traits would be highly beneficial. The review titled “Topology in Soft and Biological Matter,” recently published in Physics Reports, seeks to achieve this integration. Starting from the rigorous language of knot theory and field theories in physics to the latest computational techniques and algorithms for quantifying the topological properties of real molecules, the review presents an extensive overview of the current applications of topological concepts in mathematics, physics, chemistry, and biology. This comprehensive review marks the culmination of a four-year journey under the COST Action CA17139 EUTOPIA, coordinated internationally by Prof. Luca Tubiana of the University of Trento. Funded by the European COST program, this initiative brought together scientists from almost all European Union countries and several partners, including Turkey, Israel, and the USA. Achille Giacometti, from the Ca’ Foscari University of Venice, coordinated the EUTOPIA working group “Polymeric and Fibrous Topological Materials,” overseeing the detailed sections on polymers and viscoelasticity. The European Centre for Living Technology (ECLT), directed by Achille Giacometti, hosted the working group that completed the final draft of the review. This review represents a significant collaborative effort, with 59 scientists from various institutions across Europe and its partners contributing to this ambitious project. Through their intense cooperative efforts, the review not only highlights the state of the art but also aims to establish a unified language for topological research across diverse scientific disciplines. The study was published in the Physics Reports journal. Full link: https://doi.org/10.1016/j.physrep.2024.04.002

We have succeeded, through the use of a special laser, to make magnetic a material that is normally not such. In addition to its value for fundamental research, the most surprising finding of the study is that the magnetic effect is ten thousand times larger than theory expected. This allows the effect to potentially be used in technology as well, and some research groups are already working in this direction. Our discovery has just been published in the journal Nature. The study was originally planned to prove a theoretical prediction made a few years ago, in which it was said that if you were able to move atoms in a material in a circular trajectory, the material could become a magnet, albeit a very weak one. The original theoretical paper had been very optimistic about the size of the effect. It was at the limit of what could be observed in the lab. We decided to give it a try though, because the idea was sufficiently fascinating from a physics point of view. It allowed us to combine different symmetries of nature, which could be tested for the first time thanks to a new type of laser developed in my research group. Figure: The laser light is circularly polarized, that is, it is shaped like a “corkscrew.” When laser light with this type of polarization enters a material, it transfers its circular polarization to the atoms in it, causing them to rotate and generating atomic currents. If the frequency of the light matches the frequency of vibration of the atoms, the effect is enhanced and relatively large magnetism is generated. Adapted from Nature. Image Credit: Dunia Maccagni & Stefano Bonetti. The new type of laser works in the far infrared, with a wavelength of about 100 micrometers, or 0.1 millimeters. For comparison, visible light has a wavelength of just under 1 micrometer. In addition, the light emitted by the laser used in the study has a peculiarity: it has a polarization (the direction of oscillation of the radiation, the direction that is filtered out by, for example, polarized glasses) that is circular. That is, the light propagates in the shape of a corkscrew, as shown in the figure. This allows a circular motion to be imparted to the atoms in the material, as suggested by the theoretical prediction. There was a moment of disbelief in the lab when we realized that the effect was gigantic: the material, which appears to the eye as an ordinary glass sample, became strongly magnetic, almost as strong as real magnets! We spent two years trying to find any artifacts, because it was an experiment that had never been tried before and we had no other research groups to compare with. In fact, in addition to the magnetic effect, the measurement also showed another nonmagnetic effect that became the subject of a second publication. Having separated the magnetic effect from the nonmagnetic effect, the manuscript was ready, but the work was not finished. The discussion with the anonymous reviewers lasted more than a year and a half, which made it possible to rule out the presence of possible additional artifacts. In the meantime, similar experiments were reproduced in several other laboratories around the world that confirmed the discovery. The other labs also demonstrated its generality for a much wider class of materials (including glass itself, silica), and in some cases with even stronger magnetic effects. Why is the discovery so important? Light and matter describe almost all of the physical world we experience. Understanding their fundamental laws allows us to imagine and design new materials and technologies that can enable sustainable human existence with a finite resource planet. This study taps into a very recent branch of the physics of matter where light is used not only to study the properties of materials, but also to change their properties. As in this case, where we induced magnetic properties, otherwise absent, using light. The idea of creating new sustainable materials is the mission of the RARA Foundation – Sustainable Materials and Technologies. The two most pressing issues for our future as humanity are energy and a more sustainable technology. Both depend crucially on a common factor: materials. Finding alternative, clean, abundant materials is the only way to ensure a sustainable life for the whole planet, not just a small part of it. With the initiatives related to RARA, we want to create attention to these issues and attract the most creative minds, not only those of people who are already experts in the field, but also of our and prospective students, to try together to solve this enormous challenge.

An international research group has discovered a new state of matter characterized by the existence of a quantum phenomenon called chiral current. These currents are generated on an atomic scale by a cooperative movement of electrons, unlike conventional magnetic materials whose properties originate from the quantum characteristic of an electron known as spin and their ordering in the crystal. Chirality is a property of extreme importance in science, for example, it is fundamental also to understand DNA. In the quantum phenomenon discovered, the chirality of the currents was detected by studying the interaction between light and matter, in which a suitably polarized photon can emit an electron from the surface of the material with a well-defined spin state. The discovery significantly enriches our knowledge of quantum materials, on the search for chiral quantum phases and on the phenomena that occur at the surface of materials. The discovery of the existence of these quantum states may pave the way for the development of a new type of electronics that employs chiral currents as information carriers in place of the electron’s charge. Furthermore, these phenomena could have an important implication for future applications based on new chiral optoelectronic devices, and a great impact in the field of quantum technologies for new sensors, as well as in the biomedical and renewable energy fields. Born from a theoretical prediction, this study directly and for the first time verified the existence of this quantum state, until now enigmatic and elusive, thanks to the use of the Italian Elettra synchrotron. Until now, knowledge about the existence of this phenomenon was limited to theoretical predictions for some materials. Its observation on the surfaces of solids makes it extremely interesting for the development of new ultra-thin electronic devices. The research group, which includes national and international partners including the Ca’ Foscari University of Venice, the SPIN Institute, the CNR -Materials Officina Institute and the University of Salerno, investigated the phenomenon of a material already known to the scientific community for its electronic properties and superconducting spintronics applications, but the discovery has a broader scope, being much more general and applicable to a vast range of quantum materials. These materials are revolutionizing quantum physics and the current development of new technologies, with properties that go far beyond those described by classical physics. The study was published in the prestigious journal Nature. Full link: https://www.nature.com/articles/s41586-024-07033-8

In a significant leap forward for soft X-ray imaging, an international collaboration led by Professor Matteo Porro (EuXFEL, Germany, and Ca’ Foscari University of Venice, Italy) has achieved significant advancements with the deployment of a state-of-the-art DEPFET (Depleted Field Effect Transistor) Sensor with Signal Compression (DSSC) module. This cutting-edge 64k-pixel DEPFET module serves as a pivotal component of the DSSC, promising enhanced capabilities for capturing and measuring soft X-rays at the European XFEL. The European XFEL, located in Schenefeld, Germany, delivers up to 2700 brilliantly intense X-ray pulses within a single bunch train at a remarkable rate of 4.5MHz, with a repetition cycle of 10 Hz. This distinctive bunch scheme presents considerable challenges for imaging detector development, leading to the creation of specialized detectors, including the Large Pixel Detector (LPD), the Adaptive Gain Integrating Pixel Detector (AGIPD), and the featured DEPFET Sensor with Signal Compression (DSSC). The DSSC, tailor-made for the soft X-ray range spanning from 250 eV to 6 keV, stands out due to its 1-megapixel camera designed to detect photons within the specified energy range. Notably, the DEPFET technology utilized in the pixel sensors ensures exceptionally low input capacitance, enabling very low noise for single-photon sensitivity at a Mega frame rate. Additionally, the intrinsic capability of signal compression, without necessitating gain switching, distinguishes this technology. One DSSC module is composed of 512 × 128 hexagonal pixels, each with a side length of 136 μm. One module is read out by sixteen application-specific integrated circuits (ASICs) of 64 x 64 channels each (one per pixel) realized in 130nm CMOS technology. Each readout channel includes DEPFET-bias current cancellation circuitry, a trapezoidal-shaping filter, a 9-bit analog-to-digital converter (ADC), and an 800-word long digital memory. Assembled and characterized in a laboratory testbench at the German Electron Synchrotron (DESY), these modules exhibit impressive performance metrics. Operating at a peak frame rate of 4.5MHz, the DEPFET Sensor with Signal Compression achieves noise levels and dynamic range that meet the stringent specifications of the DSSC project. The article emphasizes the distinctive features of the DEPFET approach. This work signifies a remarkable milestone in the advancement of cutting-edge soft X-ray detectors for Photon Science applications. These innovations are poised to revolutionize imaging capabilities at the European XFEL, where scientists have the possibility to map the atomic details of viruses, decipher the molecular composition of cells, take three-dimensional images of the nanoworld, film chemical reactions, and study processes such as those occurring deep inside planets.  The DSSC consortium currently includes European XFEL, DESY, the University of Heidelberg, Politecnico di Milano, the University of Bergamo, and PNSensor GmbH, Munich.   The full article is available at the following link: https://doi.org/10.1038/s41598-023-38508-9 

The study centres on Co3Sn2S2, a magnetic Weyl kagome system. The kagome lattice, a hexagonal network of interconnected triangles, has been a subject of intense scientific interest due to its distinctive geometry and potential for hosting topological phases. Co3Sn2S2, in particular, exhibits intriguing properties such as high-electron density flat bands, Dirac states, and the presence of Fermi arcs. These are unique properties of the electronic band structure that offer exciting possibilities for novel electronic and quantum devices. The researchers investigated, led by Federico Mazzola, the surface terminations of Co3Sn2S2, focusing on how different terminations affect the connectivity of Weyl points, which are monopoles of Berry curvature responsible for anomalous Hall effects and topological surface states. Scanning tunnelling microscopy (STM) studies had suggested the presence of multiple surface terminations in Co3Sn2S2, and this research aimed to clarify their impact on electronic properties. By utilizing micro-angle-resolved photoelectron spectroscopy (micro-ARPES) and first-principles calculations, the team measured the energy-momentum spectra and Fermi surfaces for different surface terminations of Co3Sn2S2. The results revealed that the type of termination significantly influenced the electronic properties and topological features of the material. Notably, the researchers observed termination-dependent Fermi arcs that connect Weyl points in distinct ways, suggesting that the surface environment plays a crucial role in shaping the material’s topological connectivity. The study’s findings have broad implications for the field of materials science and quantum electronics. The ability to control topological properties by manipulating surface electrostatic potentials opens up new avenues for designing responsive magnetic spintronics devices and harnessing the unique electronic characteristics of materials like Co3Sn2S2. This research represents a significant step toward understanding and harnessing topological phases in materials, paving the way for innovative applications in fields such as spintronics, superconductors, and low-voltage electronics. The study’s combination of experimental and theoretical approaches provides a comprehensive view of the interplay between surface terminations and topological properties, offering valuable insights for future material design and engineering. The full article is available at the following link: https://doi.org/10.1021/acs.nanolett.3c02022

Graphene, the wonder two-dimensional material, has shown exceptional electronic properties, making it a sought-after candidate for various advanced technologies. However, maintaining high carrier mobility in practical device applications has been a challenge, with the choice of substrate and encapsulation playing a pivotal role. A team of researchers, including Dr Domenico De Fazio at the Ca’ Foscari University of Venice, has made a breakthrough in this domain by successfully encapsulating graphene in tungsten disulfide (WS2). This achievement, detailed in a recent paper, offers an alternative to the commonly used hexagonal boron nitride (hBN) encapsulation method. The researchers applied a chemical treatment involving a super-acid, bis(trifluoromethane) sulfonimide (TFSI), to overcome the hysteresis and enhance the mobility of graphene encapsulated in WS2. High mobility, a key requirement for electronic devices, was achieved through WS2 encapsulation, presenting numerous advantages. The study revealed a significant reduction in hysteresis, making WS2-encapsulated graphene a compelling alternative to hBN. This breakthrough has far-reaching implications for various electronic applications, including field-effect transistors, modulators, photodetectors, and sensors. With hBN’s limitations addressed by WS2, the world of graphene-based electronics may soon see significant improvements in performance and scalability, paving the way for more efficient and powerful devices. The full article is available at the following link: https://doi.org/10.1063/5.0151273

The Organizing Committee is glad to announce ISIPM-11 & FLM2023 in Venice, a three-day meeting that will be held at the Scientific Campus of Ca’ Foscari University of Venice on November 22-24, 2023. JAIPC – Japanese Association of Inorganic Phosphorus Chemistry  and  DSMN – Department of Molecular Sciences and Nanosystems of Ca’ Foscari University of Venice  have created a joint forum where experts in materials research fields and young researchers can discuss face-to-face about novel ideas and projects in a widespread range of topics. ISIPM-11 – 11th International Symposium on Inorganic Phosphate Materials is organized by JAIPC with the aim to become a memorable platform for the presentation of recent development and the promotion of fundamental and technological research activities on inorganic phosphate materials. FLM2023 – International Workshop on Forward-Looking Materials, promoted by DSMN, is devoted to the most promising research lines on design, preparation, characterization and application of innovative smart materials. More information can be found by visiting the Conference website at  unive.it/isipm11-flm2023. Please note that the Call for Abstracts is open July 1-31, 2023.

In an international collaboration involving experiments and theory, the topological wrapping of electrons in matter, which refers to the curvature of the space in which they exist and move, has been measured in a new class of materials. This new discovery could lead to a deeper understanding of quantum materials, which are materials where the collective behavior of the electrons that make them up generates new properties that can only be interpreted using the laws of quantum mechanics. These materials are expected to have future applications in various technological fields, from renewable energies to biomedicine, and from electronics to quantum computers. Using advanced experimental techniques that utilize light generated by a particle accelerator called a synchrotron, and thanks to modern modeling techniques of material behavior, it has been possible to measure the wrapping of electrons for the first time, in relation to the concept of topology. Just as a soccer ball and a donut have different topological properties related to their shapes (for example, the donut has a hole while the soccer ball does not), the behavior of electrons in materials is influenced by certain quantum properties that determine their wrapping, similar to how the trajectory of light in the universe is modified by the presence of stars, black holes, dark matter, and dark energy, which bend space and time. Although this particular characteristic of electrons has been known for many years, no one had been able to directly measure this “topological wrapping” until now. By exploiting an effect known as circular dichroism (from the Greek “di-” meaning two and “chroma” meaning color), which means that materials absorb light differently depending on its polarization, it has been possible to obtain this measurement for the first time. In addition to using this particular experimental technique available only at a synchrotron source, the synergy with theoretical analysis has been particularly relevant. In fact, the theoretical researchers on the team employed sophisticated quantum simulations made possible only through the use of powerful supercomputers, thus guiding the experimental colleagues towards the specific region of the material’s electronic properties where it was possible to measure the effect related to circular dichroism. Achieving this feat was the result of an international collaboration of scientists, including CNR-IOM in Trieste, the University of Bologna, Ca’ Foscari University in Venice, the University of Milan, the University of Würzburg (Germany), the University of St. Andrews (UK), Boston College, and the University of Santa Barbara (United States). The class of materials that the team focused on is called Kagome materials, named after their close resemblance to the pattern of bamboo threads in a traditional Japanese basket. These materials are revolutionizing quantum physics due to their magnetic, topological, and superconducting properties. This new discovery promises to revolutionize the way quantum materials will be studied in the future, thereby opening the doors to new developments in quantum technologies. The study has been published in the journal Nature Physics, D. Di Sante et al. “Flat band separation and robust spin Berry curvature in bilayer kagome metals.” The full article is available at the following link: https://www.nature.com/articles/s41567-023-02053-z

As part of the Engineering Physics colloquia monthly held at the Ca’ Foscari University of Venice, renowned researcher and former Italian minister Maria Chiara Carrozza was honoured with the “Emmy Noether Lecture Award” for her exceptional contributions to the fields of science, technology, and public service. Carrozza, currently serving as the President of the National Research Council of Italy (CNR), was recognized for her groundbreaking work and outstanding leadership in the pursuit of scientific advancements. The Emmy Noether Lecture Award is an accolade which will be presented yearly to individuals who have demonstrated exemplary achievements in the fields of physics and engineering, embodying the spirit of innovation, determination, and societal impact. Named after the pioneering German mathematician Emmy Noether, the award serves as a testament to the recipient’s outstanding intellectual contributions. Carrozza’s illustrious career spans both academia and public service, where she has consistently pushed the boundaries of scientific research while working tirelessly to translate her discoveries into tangible benefits for society. As the President of the CNR, she has played a pivotal role in fostering collaboration between academia, industry, and government to drive innovation and stimulate economic growth. Throughout her career, Carrozza has made significant breakthroughs in the field of robotics and assistive technologies, revolutionising the way we understand human-machine interactions and providing novel solutions to improve the quality of life for individuals with disabilities. Her research has paved the way for advancements in neuroprosthetics, wearable robotics, and rehabilitation engineering, earning her international recognition and acclaim. Carrozza’s exceptional leadership skills and passion for knowledge dissemination have also been instrumental in shaping science and technology policies at both national and international levels. Her previous role as the Italian Minister of Education, University, and Research allowed her to promote scientific literacy and establish strategic partnerships to foster interdisciplinary collaboration and innovation. Upon receiving the prestigious Emmy Noether Lecture Award, Carrozza expressed her deep gratitude and emphasised the importance of interdisciplinary research in addressing the complex challenges of our time. The ceremony at Ca’ Foscari University of Venice was attended by the Rector of the University Tiziana Lippiello, the Director of the Department of Molecular Sciences and Nanosystems Maurizio Selva and by the renowned physicist and SuperVenice member Guido Caldarelli, who gave a short lecture on the Noether’s theorem. The session was chaired by the coordinator of the Engineering Physics course Stefano Bonetti. Through a journey across her past activities in the world of science and technology, Carrozza emphasised the role of research institutions and universities in driving technological advancements and nurturing the next generation of innovators. The conferral of the Emmy Noether Lecture Award upon Maria Chiara Carrozza not only celebrates her remarkable achievements but also inspires aspiring female researchers and young minds to pursue scientific excellence and contribute to the betterment of society. Her commitment to pushing the boundaries of knowledge and harnessing technology for the greater good serves as an exemplary model for generations to come.

Real systems like our cities can have their digital versions, called “digital twins,” which are now possible due to the development in the fields of sensors and artificial intelligence. However, to transform these “doubles” from mere digital replicas to reliable tools for understanding the world and predicting behaviors, they need to be combined with the science of complexity. This is the key to creating cities that are genuinely human-centered. This is what a group of scientists, including Guido Caldarelli, a physicist at Ca’ Foscari University of Venice, argue in an article in Nature Computational Science. Digital twins are highly detailed replicas of real systems, including human bodies, cities, or the entire world, created by feeding representations of the elements of the respective system of interest into “black boxes.” This allows them to learn to behave more and more similarly to the corresponding elements of the real world. Digital twins can be used to study alternative scenarios and to control the real system based on artificial intelligence. However, “doubles” do not necessarily mean that digital twins behave realistically. Neither is there any advantage in creating a perfect copy of a system without understanding either the system or its simulation. Beyond issues related to big data and machine learning, local digital twins often oversimplify aspects such as social and cultural life and anything that is not represented by data. This includes everything that is immeasurable, such as friendships, love, and quality of life – things that are terribly important to humans but not to computer models, artificial intelligence, and robots. Therefore, Guido Caldarelli and his colleagues emphasize the need for digital twins to be combined with the science of complexity. This, they write, is the key to understanding global behaviors and not just a mere repetition inside the computer. The science of complex systems studies dynamic systems made up of many elements, which typically interact with each other or with other systems in a nonlinear way. Such systems often take the form of a network and can be layered several times, forming networks of networks. Taking interactions into account is essential for understanding the nature of complex systems, which cannot be understood solely from the properties of their individual parts. Nonlinear and network interactions are often the cause of emerging system properties. One can also speak of self-organization from the bottom up. Cities are full of these phenomena. They can range, for example, from the formation of uniform lines of walking directions on sidewalks to patterns of stopping and restarting traffic flows, or patterns of segregation between people with different cultural backgrounds, as Nobel Prize winner Thomas Schelling has shown. “As a consequence,” explains Guido Caldarelli, “digital twins not only need to consider the science of complexity to become useful and reliable tools. It is not even enough to plan, optimize, and control cities from the top down. To create cities for people, it is crucial to anticipate opportunities for self-organization, participation, and co-evolution.” Real systems like our cities can have their digital versions, called “digital twins,” which are now possible due to the development in the fields of sensors and artificial intelligence. However, to transform these “doubles” from mere digital replicas to reliable tools for understanding the world and predicting behaviors, they need to be combined with the science of complexity. This is the key to creating cities that are genuinely human-centered. This is what a group of scientists, including Guido Caldarelli, a physicist at Ca’ Foscari University of Venice, argue in an article in Nature Computational Science. Digital twins are highly detailed replicas of real systems, including human bodies, cities, or the entire world, created by feeding representations of the elements of the respective system of interest into “black boxes.” This allows them to learn to behave more and more similarly to the corresponding elements of the real world. Digital twins can be used to study alternative scenarios and to control the real system based on artificial intelligence. However, “doubles” do not necessarily mean that digital twins behave realistically. Neither is there any advantage in creating a perfect copy of a system without understanding either the system or its simulation. Beyond issues related to big data and machine learning, local digital twins often oversimplify aspects such as social and cultural life and anything that is not represented by data. This includes everything that is immeasurable, such as friendships, love, and quality of life – things that are terribly important to humans but not to computer models, artificial intelligence, and robots. Therefore, Guido Caldarelli and his colleagues emphasize the need for digital twins to be combined with the science of complexity. This, they write, is the key to understanding global behaviors and not just a mere repetition inside the computer. The science of complex systems studies dynamic systems made up of many elements, which typically interact with each other or with other systems in a nonlinear way. Such systems often take the form of a network and can be layered several times, forming networks of networks. Taking interactions into account is essential for understanding the nature of complex systems, which cannot be understood solely from the properties of their individual parts. Nonlinear and network interactions are often the cause of emerging system properties. One can also speak of self-organization from the bottom up. Cities are full of these phenomena. They can range, for example, from the formation of uniform lines of walking directions on sidewalks to patterns of stopping and restarting traffic flows, or patterns of segregation between people with different cultural backgrounds, as Nobel Prize winner Thomas Schelling has shown. “As a consequence,” explains Guido Caldarelli, “digital twins not only need to consider the science of complexity to become useful and reliable tools. It is not even enough to plan, optimize, and control cities from the top down. To create cities for people, it is crucial to anticipate opportunities for self-organization, participation, and co-evolution.” Link to the original article: https://www.nature.com/articles/s43588-023-00431-4