Collaborative platforms for streamlining workflows in Open Science

Despite the internet’s dynamic and collaborative nature, scientists continue to produce grant proposals, lab notebooks, data files, conclusions etc. that stay in static formats or are not published online and therefore not always easily accessible to the interested public. Because of limited adoption of tools that seamlessly integrate all aspects of a research project (conception, data generation, data evaluation, peer-reviewing and publishing of conclusions), much effort is later spent on reproducing or reformatting individual entities before they can be repurposed independently or as parts of articles.

We propose that workflows - performed both individually and collaboratively - could potentially become more efficient if all steps of the research cycle were coherently represented online and the underlying data were formatted, annotated and licensed for reuse. Such a system would accelerate the process of taking projects from conception to publication stages and allow for continuous updating of the data sets and their interpretation as well as their integration into other independent projects.

A major advantage of such workflows is the increased transparency, both with respect to the scientific process as to the contribution of each participant. The latter point is important from a perspective of motivation, as it enables the allocation of reputation, which creates incentives for scientists to contribute to projects. Such workflow platforms offering possibilities to fine-tune the accessibility of their content could gradually pave the path from the current static mode of research presentation into
a more coherent practice of open science

Phonon-assisted decoherence and tunneling in quantum dot molecules

We study the influence of the phonon environment on the electron dynamics in a doped quantum dot molecule. A non-perturbative quantum kinetic theory based on correlation expansion is used in order to describe both diagonal and off-diagonal electron-phonon couplings representing real and virtual processes with relevant acoustic phonons. We show that the relaxation is dominated by phonon-assisted electron tunneling between constituent quantum dots and occurs on a picosecond time scale. The dependence of the time evolution of the quantum dot occupation probabilities on the energy mismatch between the quantum dots is studied in detail.Comment: 4 pages, 2 figures, conference proceeding NOEKS10, to be published in Phys. Stat. So

Theory of phonon-mediated relaxation in doped quantum dot molecules

A quantum dot molecule doped with a single electron in the presence of diagonal and off-diagonal carrier-phonon couplings is studied by means of a non-perturbative quantum kinetic theory. The interaction with acoustic phonons by deformation potential and piezoelectric coupling is taken into account. We show that the phonon-mediated relaxation is fast on a picosecond timescale and is dominated by the usually neglected off-diagonal coupling to the lattice degrees of freedom leading to phonon-assisted electron tunneling. We show that in the parameter regime of current electrical and optical experiments, the microscopic non-Markovian theory has to be employed.Comment: Final extended version, 5 pages, 4 figure

Phonon-assisted tunneling between singlet states in two-electron quantum dot molecules

We study phonon-assisted electron tunneling in semiconductor quantum dot molecules. In particular, singlet-singlet relaxation in a two-electron doped structure is considered. The influence of Coulomb interaction is discussed via comparison with a single electron system. We find that the relaxation rate reaches similar values in the two cases but the Coulomb interaction shifts the maximum rates towards larger separations between the dots. The difference in electron-phonon interaction between deformation potential and piezoelectric coupling is investigated. We show that the phonon-induced tunneling between two-electron singlet states is a fast process, taking place on the time scales of the order of a few tens of picoseconds.Comment: Final extended version, 8 pages, 9 figure

Zero-Phonon Line Broadening and Satellite Peaks in Nanowire Quantum Dots: The Role of Piezoelectric Coupling

We investigate the influence of the one-dimensional character of the phonon modes in a catalytically grown GaAs nanowire on the absorption spectrum of an embedded quantum dot, focusing on the contribution from the piezoelectric coupling. In general, the reduced dimensionality of the phonons leads to spectral side peaks and a zero-phonon line broadening due to the energetically lowest (acoustic) phonon mode. While the deformation potential predominantly couples to radial modes, the piezoelectric interaction can also couple strongly to modes of axial character, leading to additional absorption features. The contribution of the piezoelectric coupling to the zero-phonon line is negligible.Comment: 4 pages, 5 figures, to appear in Physica Status Solidi B (simulation parameters and figures changed, minor changes in text

Procjena kvalitete i upravljanje onečišćenim sedimentima: potrebna kakvoća podataka – od molekularne razine do razine riječnih bazena

Management of environmental risks in river basins needs to address quality aspects of sediment – both because of its storage capacity for contaminants and due to its potential function as a secondary source of pollution. Assessment of sediment quality, however, is still prone to a number of uncertainties and insufficient information with regard to regulation, analytical methods, risk assessment and risk management. The European Water Framework Directive (WFD), e.g., has not come up with environmental quality standards for sediments. Lack of harmonization, representativeness and traceability of sediment data, not fully understood processes governing bioavailability of sediment-bound contaminants, all add up to the uncertainty that needs to be quantified. This paper details uncertainties ranging from the molecular to the basin scale level with regard to sediment quality assessment and its integration into management approaches, and it suggests ways of how to cope with a lack of data and insecure data while still developing an overview of basin wide risks.Upravljanje rizicima po okoliš u riječnim bazenima treba sadržavati i aspekt kvalitete sedimenata – zbog njihovog kapaciteta za pohranu onečišćivala, ali i zbog njihove potencijalne uloge kao sekundarnog izvora zagađenja. Međutim, procjena kvalitete sedimenata ograničena je nekim nepoznanicama i nedovoljnim brojem podataka koji se odnose na propise, analitičke metode, procjenu rizika i njegovo upravljanje. Europska direktiva za vode (European Water Framework Directive – WFD) nije još uvijek donijela standard za okolišnu kakvoću sedimenata. Nedostatak harmonizacije, reprezentativnosti i dostupnosti podataka za sedimente, kao i nedovoljno poznati procesi koji upravljaju biološkom dostupnošću onečišćivala sadržanih u sedimentu doprinose stupnju neizvjesnosti koji je potrebno kvantificirati. U radu su opisane neizvjesnosti, u rasponu od molekularne razine do razine riječnih bazena, s obzirom na postupak procjene kvalitete sedimenata i integriranje tog postupka u upravljačke sustave, uz predlaganje načina kako se usprkos nedostatku podataka ili njihovoj upitnosti mogu primijeniti metodologije procjene rizika na razini riječnih bazen