A5022292209- Physics of Superconductivity and Magnetism
- Advanced Condensed Matter Physics
- Theoretical and Computational Physics
- Fatigue and fracture mechanics
- Fusion materials and technologies
- Nuclear reactor physics and engineering
- Magnetic confinement fusion research
- Microstructure and mechanical properties
- Material Properties and Failure Mechanisms
- Nuclear Engineering Thermal-Hydraulics
- Metallurgy and Material Forming
- Hydrogen embrittlement and corrosion behaviors in metals
- High-pressure geophysics and materials
- Microstructure and Mechanical Properties of Steels
- Electrostatics and Colloid Interactions
- Quantum many-body systems
- Magnetic and transport properties of perovskites and related materials
- Force Microscopy Techniques and Applications
- Spectroscopy and Quantum Chemical Studies
- Superconducting Materials and Applications
- Combustion and Detonation Processes
- Material Dynamics and Properties
- Mobile Agent-Based Network Management
- Distributed systems and fault tolerance
- Composite Material Mechanics
Jožef Stefan Institute
2015-2024
Uppsala University
2019
University of Ljubljana
2003-2006
The plasma diagnostic and control (D&C) system for a future tokamak demonstration fusion reactor (DEMO) will have to provide reliable operation near technical physics limits, while its front-end components be subject strong adverse effects within the nuclear high temperature environment. ongoing developments ITER D&C represent an important starting point progressing towards DEMO. Requirements detailed exploration of are however pushing design using sophisticated methods aiming large spatial...
An initial concept for the plasma diagnostic and control (D&C) system has been developed as part of European studies towards development a demonstration tokamak fusion reactor (DEMO). The main objective is to develop feasible, integrated design DEMO D&C that can provide reliable high performance (electricity output) over extended periods operation. While power maximized when operating near operational limits tokamak, reliability operation typically improves choosing parameters significantly...
We show how to generalise the zero temperature Lanczos method for calculating dynamical correlation functions finite temperatures. The key is microcanonical ensemble, which allows us replace involved canonical ensemble with a single appropriately chosen state; in thermodynamic limit it provides same physics as but evaluation of expectation value. can employ system sizes temperature, whereas statistical fluctuations present small systems are prohibitive, spectra largest surprisingly smooth....
We analyze the high-temperature conductivity in one-dimensional integrable models of interacting fermions: t-V model (anisotropic Heisenberg spin chain) and Hubbard model, at half-filling regime corresponding to insulating ground state. A microcanonical Lanczos method study for finite size systems reveals anomalously large finite-size effects low frequencies while a frequency-moment analysis indicates d.c. conductivity. This phenomenon also appears prototype quantum system impenetrable...
We study the electron spin resonance of low-dimensional systems at high temperature and test Kubo-Tomita theory exchange narrowing. In finite-size (molecular magnets), we found a double-peak which strongly differs from usual Lorentzian. For infinite systems, have predictions for linewidth line shape as function anisotropy strength. this, used an interpolation between nonperturbative calculation memory short times (exact diagonalization) hydrodynamic diffusion long times. show that...
Dynamics of the Taylor bubble interface in vertical counter-current flow was analyzed with video recordings at 100 – 800 frames per second. bubbles air-water mixture were studied on time intervals up to several minutes stagnant conditions, where buoyancy is dynamically balanced by inertial drag downward turbulent flow. length from 4 10 cm observed a pipe 26 mm diameter Reynolds numbers based liquid superficial velocity around 6000. Algorithms, developed for analysis dedicated cap and body...
The dc magnetization and the electron spin resonance (ESR) measurements have been performed on $\ensuremath{\alpha}\text{\ensuremath{-}}\mathrm{Na}\mathrm{Mn}{\mathrm{O}}_{2}$ polycrystalline sample, a quantum system frustrated two-dimensional (2D) triangular lattice with spatially anisotropic Heisenberg exchange. former reveal realization of high-spin state $(S=2)$ magnetic ${\mathrm{Mn}}^{3+}$ sites. From susceptibility curve, we determined nearest-neighbor antiferromagnetic exchange...
Crystal plasticity finite element models have been extensively used to simulate various aspects of polycrystalline deformations. A common weakness practically all lies in a relatively large number constitutive modeling parameters that, principle, would require dedicated measurements on proper length scales order perform reliable model calibration. It is important realize that the obtained data at different should be properly accounted for models. In this work, two-scale calibration procedure...
A simple analytical model of intergranular normal stresses is proposed for a general elastic polycrystalline material with arbitrary shaped and randomly oriented grains under uniform loading. The provides algebraic expressions the local grain-boundary-normal stress corresponding uncertainties, as function grain-boundary type, its inclination respect to direction external loading material-elasticity parameters. knowledge necessary prerequisite in any damage modeling approach, e.g., predict...
We report measurements of the specific heat quantum spin liquid system $\mathrm{Sr}{\mathrm{Cu}}_{2}{(\mathrm{B}{\mathrm{O}}_{3})}_{2}$ in continuous magnetic fields $H$ up to $33\phantom{\rule{0.3em}{0ex}}\mathrm{T}$. The data, when combined with a finite temperature Lanczos diagonalization Shastry-Sutherland Hamiltonian, indicate presence nearest neighbor Dzyaloshinsky-Moriya (DM) interaction that violates crystal symmetry. Moreover, same DM is required explain observed electron resonance...
Two-dimensional suspensions of spherical colloids subject to periodic external fields exhibit a rich variety molecular crystalline phases. We study in simulations the ground state configurations dimeric and trimeric systems, that are realized on square triangular lattices, when either two or three macroions trapped each potential minimum. Bipartite orders checkerboard stripe types reported together with more complex quadripartite orderings, shortcomings envisioning gathered single minimum as...
High resolution neutron scattering measurements on a single crystal of ${\mathrm{SrCu}}_{2\ensuremath{-}x}{\mathrm{Mg}}_{x}({\mathrm{BO}}_{3}{)}_{2}$ with $x\ensuremath{\sim}0.05$ reveal the presence new spin excitations within gap this quasi-two-dimensional, singlet ground state system. The application magnetic field induces Zeeman-split states associated $S=1/2$ unpaired spins which are antiferromagnetically correlated bulk singlet. Substantial broadening both one- and two-triplet in doped...
The properties of the polaron and bipolaron are explored in one-dimensional Jahn-Teller model with dynamical quantum phonons. ground-state computed using a recently developed variational method. Dynamical ground state investigated by calculating optical conductivity $\ensuremath{\sigma}(\ensuremath{\omega}).$ Our numerical results suggest that Holstein polarons similar. However, strong-coupling regime qualitative differences $\ensuremath{\sigma}(\ensuremath{\omega})$ between two models found...