V001 / JSI

Dr Jaka Vodeb from Department of Complex Matter at the Jožef Stefan Institute has published a study in Nature Physics in which he has used quantum simulation to gain valuable insight into a well-known physical phenomenon, the false vacuum decay. Together with colleagues from the University of Leeds, the Forschungszentrum Jülich, where Dr Vodeb did his postdoctoral education, and the Austrian Institute of Science and Technology (ISTA), they sought to understand the key puzzle of the false vacuum decay and the mechanism behind it. The experiment involved placing 5564 qubits - the basic building blocks of quantum computing - in specific configurations to represent a false vacuum. By carefully controlling the system, they were able to trigger a transition from a false vacuum to a real vacuum, mirroring the formation of bubbles as described by the theory of false vacuum decay. Although this process could trigger a significant change in the structure of the Universe, predicting its timing is difficult; it is likely to occur over a period that could last millions or even billions of years.

An international team of scientists published an article First-order quantum breakdown of superconductivity in an amorphous superconductorin the journal Nature Physics. Mikhail Feigel’man from Jožef Stefan Institute (Dept. of Complex Matter F7) and the CENN Nanocenter, in collaboration with researchers from the Neel Institute (CNRS Grenoble) and Karlsruhe Institute of Technology, provided a groundbreaking framework for understanding of unexpected experimental demonstration of sharp disappearance of superconductivity of thin films at ultra-low temperatures, upon increase of their normal-state resistance, that is in sharp contrast with standard paradigm of continuous (second-order) superconducting-insulator transitions existing for more than three decade. The first-order nature of this transition is understood in terms of energy competition between two low-temperature states of matter: the superconducting condensate of electron pairs on one hand, and the insulator made out of bound electron pairs with Coulomb repulsion between them, on another hand.

Dr. Anna Razumnaya from the Jožef Stefan Institute, in collaboration with researchers from the University of Picardie, IFW Dresden, the University of Toronto, and Terra Quantum AG, published a review article Topological Foundations of Ferroelectricity in the prestigious journal Physics Reports. The study presents the fundamental role of topology in ferroelectric materials and provides a groundbreaking framework for understanding and classifying complex polarization structures in nanostructured ferroelectric, paving the way for technological applications. By drawing parallels between hydrodynamics and electrostatics, this research demonstrates how fundamental topological concepts can be applied to ferroelectric materials to better understand and manipulate their polarization structures. This study opens new prospects for the development of polar materials, including traditional ferroelectrics and newly discovered soft ferroelectric materials, while also advancing the frontiers of their potential applications in cutting-edge electronic devices.

Matjaž Gomilšek from the Condensed Matter Physics Department at the Jožef Stefan Institute and the Faculty of Mathematics and Physics, University of Ljubljana has published a paper Anisotropic Skyrmion and Multi-q Spin Dynamics in Centrosymmetric Gd₂PdSi₃ in Physical Review Letters as the leading author, together with co-authors from the UK, Switzerland, Germany, Canada, and Japan. In the paper they discover a pronounced directional dependence of magnetic dynamics in topologically-protected whirls of magnetization called skyrmions. The observed behavior is very unusual, since the studied material is highly symmetrical. The researchers also discover a strong directional dependence of magnetic dynamics in the previously-unidentified ground state of the material, which suggests that it is the much-sought-after lattice of merons (“halves” of a skyrmion). These discoveries significantly contribute to solving the puzzle of the stability of topological magnetic textures in highly symmetrical materials. Skyrmions can be used for data storage, spintronics (a magnetic analogue of electronics), or as a platform for advanced (reservoir-computing) artificial intelligence.