December 10th, 2011

The current research of materials and processes delves progressively into micro- and nano- (on spatial scale) and to femtolevel (in time-domain). Mesoscopic systems and phenomena lie in between the macro world and atomic dimensions. Such spatial scale is a challenge for the current theories as both, the ones developed to describe macroscopic bodies as well as the theories for isolated atoms and molecules, fail. On the other hand, the meso-range of dimensions and processes hides potential for numerous innovative approaches for sensorics and informatics, and is also pertinent when talking of living systems (covering loosely the size range between viruses and bacteria). Hence, there is a need for new theoretical approaches and closely related experimental studies in order to "bridge" the gap between the atomic and macro dimensions. The distinguishing feature of the proposed research centre is the unification of theoretical and experimental groups in solving one common task: How do atomic and macroscopic processes and properties interconnect on mesolevel?

The research is focused on three closely interrelated topics

T1. Coherence

The very essence of mesophysics is the extension of quantum coherence from atomic to macroscopic dimensions. Phenomena like superconductivity and superfluidity (Bose-Einstein condensation in general), ferromagnetic and ferroelectric ordering, and plasmonic resonances are important examples of such effects, all to be studied by the CoE. It is also important to know how these phenomena can be "squeezed down" to lower dimensions and confined geometries (e.g., "downscaling" of optical coherence into nanodimensions via plasmonic effects).

T2. Dynamics

While linear dynamical approaches (T1) are to a certain extent applicable to systems with a fixed structure, they (i) do not account for all phenomena in such systems and (ii) they fail to describe structural changes (formation of structures) in mesosystems. As a solution, nonlinear models of energy localization and defect formation in microsolids will be developed and tested in experiments. Transport processes in mesostructured systems are important both for their formation (synthesis, e.g. in sol-gel technology) as well as for functioning (e.g., in living cells) of such structures. An important problem to be addressed here, is how from uncorrelated molecular events a directed transport arises ("molecular ratchet").

T3. Structures

Conquering the mesodimension necessarily presumes mastering of the methods of fabrication and understanding of the structure formation in mesosystems. This is a prerequisite for the studies of both mesoscopic coherence (T1) and dynamics (T2). Results on nonlinear dynamics (T2) are closely related and give an essential support to this topic. The CoE addresses phenomena like defect formation, "stripe structures" and incommensurate modulation, cracking of sol-gel films, molecular recognition in living cells. A particular emphasis is put on low-dimensional (2D, 1D, "0D") systems, as far as (i) the dimension modifies the physical properties in the most drastic way and (ii) the novel methods of material preparation have made the fabrication of such systems viable.

These problems will be addressed by theoretical modeling, numerical simulations and various experimental techniques. The latter involves different spectroscopic (absorbtion, fluorescence, Raman), microscopic (optical, electron, SPM) and combined (micro-Raman) methods. Existing international collaborations extend the scope of available methods to synchrotron and neutron scattering. The systems to be investigated within the aforementioned studies include metal-oxide sol-gel systems of various shapes (films, fibers, micro- and nanotubes, nanopowders) activated with metal nanoparticles and semiconductor nanodots; plasmonic metal mesostructures; carbon-based structures (CNT and graphene + adsorbates); droplets of quantum liquids 4He & 3He; superconductors including HTSC; frustrated quasi-2D magnetics; biological cell membranes and receptors, microtubules (cytoscelecton). Methods such as sol-gel synthesis, laser ablation, pyrolysis, ion-beam, and colloidal lithography will be used in sample preparation.