Quantum effects in arrays of nanocrystals (QEAN)

Recent years have seen explosive growth of interest in the physics of arrays of nanocrystals: a new class of artificially manufactured materials with programmable properties which can be modified by altering the nanocrystal composition and size. Arrays of nanocrystals include various granular systems containing metallic, ferromagnetic or superconducting granules, artificially prepared arrays of quantum dots or superconducting tunnel junctions. The modern technologies allow for preparing the arrays with the size of a basic unit varying from 1 up to 100 nm. Due to a drastic decrease of a nanocrystal size the thermodynamic and transport properties of arrays are governed by specific interplay between quantum-mechanical effects and mesoscopic phenomena. The recent discoveries boosted this field of research. E.g. it is a metal-insulator transition and cotunneling in granular systems, quantum phase transition in chains of small Josephson junctions, observation of a giant enhancement of macroscopic quantum tunneling (MQT) in layered high-TC superconductors. These quantum effects are due to a peculiar interplay of quantum-mechanical tunneling between nanocrystals, Coulomb interactions, and disorder and/or superconducting fluctuations. From the theoretical point of view the arrays of nanocrystals is a particular example of strongly interacting many-body systems, and, therefore, the development of the adequate methods and models allowing analysis and description of such structures is of a great fundamental interest.

The main purpose of the Workshop is to bring together the leading experts in study of thermodynamic and transport properties of diverse nanostructured systems. The workshop time will be devoted to joint research, discussions and invited talks focused on recent experiments and theoretical approaches.

The topics to be discussed at the workshop are as follows:

·        Theoretical approaches to description of arrays of nanocrystals

·        Arrays of metallic/magnetic granules

·        Arrays of semiconductor quantum dots

·        Mesoscopic superconducting tunneling junction arrays, layered high-TC superconductors

·        Arrays of Josephson p-junctions

·        Nonlinear excitations in the arrays of nanocrystals

·        Dissipation, decoherence and noise effects

·        Shuttling: spin and charge transfer

We plan to concentrate along the following lines of research that will be carried out by the corresponding working teams:

1.    Application of p-junction arrays in superconducting quantum circuits2.    Quantum effects in hybrids involving multiband superconductors: proximity effects and Leggett modes

3.    Macroscopic quantum tunneling (MQT) and coherence (MQC) in unconventional (d-wave) Josephson junctions

4.    Mesoscopic superconducting tunneling arrays: macroscopic quantum tunneling and Coulomb blockade

5.    Nonlinear excitations in arrays of nanocrystals

6.    Kondo Shuttling in Nanoelectromechanical Single-Electron Transistors

7.    Mesoscopic fluctuations, noise and decoherence phenomena in superconducting, magnetic, and single spin devices

8.    Hopping conductivity in arrays of superconductor, semiconductor quantum dot and one-dimensional arrays of metallic granules