Selected projects

Christopher Gies

Quantum reservoir computing (QRC) is a novel computing concept at the intersection of quantum computing and artificial neural networks. In contrast to gate-based quantum computing, the reservoir ansatz loosens the strict requirements of complete control over. Instead, a loose network of quantum systems that are connected by a random coupling topology is trained to perform computational or classification tasks.

Two great advantages come with the inherent quantumness suggested by PhotonicQRC: As a quantum machine learning ansatz, quantum input can be processed natively without the need to represent it in a classical form. Secondly, the exponential size of the Hilbert space allows to treat complex tasks with extremely small physical networks.

Christopher Gies

Many applications in quantum information technology require reliable sources of quantum light. The QuantERA project EQUAISE is rooted in the Applied Quantum Science (AQS) topic and aims at developing an industry-level scalable platform for single-photon sources based on strain-engineered quantum emitters made from two-dimensional semiconductors. The project consortium involves partners from Italy, Poland, Spain, and Germany. Project start on a national level is currently pending.

Michael Sentef

In density functional theory, the total energy must be a linear function of the number of electrons for non-integer values with derivative discontinuities at integer values. Using standard generalized gradient approximation (GGA), this linearity is destroyed and the total energy functional becomes a convex function, resulting in an over-delocalization of electrons in defect states. Using hybrid functionals the linearity can be restored, although the form of the right hybrid functional is usually system dependent. The goal of this project is to implement the long-range corrected hybrid functional formalism in the density functional tight binding (DFTB) framework for periodic systems. Combining it with the time dependent formalism (TD-LC-DFTB), we will be able to describe the temperature-dependent electronic and optical properties of various materials. The application of this state-of-the-art scheme, combined with advanced spectroscopy measurements could lead to significant advances in fields like excitonics and light-energy conversion.

Supported by: DFG

Lucio Colombi Ciacchi

Particle-stabilized emulsion systems see widespread use in diverse areas such as floatation, water remediation, cosmetics, pharmaceutics as well as in materials processing of composites and ceramics. The aim of this project is to link the molecular details of heterogeneous and multi-component oil/water interfaces containing a mixture of both surfactant molecules and nanoparticles to the macroscopic behavior of these films. To achieve this aim, we plan to access a set of characteristic observables both from experiments (performed in the Advanced Ceramics group) and from atomistic and mesoscopic simulations. With the help of enhanced molecular dynamics methods we will predict interaction free-energies and the dissipative behaviour of naoparticles at surfactant-laden interfaces and develop a coarse-grained model for the discrete-element modelling of large nanoparticle films.

Supported by: DFG

Lucio Colombi Ciacchi

Valuable elements can be recovered from waste slags through a process of smelting and controlled cooling which leads to separable crystals (Engineered Artificial Minerals, EnAM) enriched with the elements of interest. In this project we will implement a rational methodology for the identification and characterization of EnAM phases rich in refractory metal elements (especially Ta, Nb, Mo) from metallurgical tin and copper slags. The methodology is based on the supervised exploration of the compositional phase space of the slags, in order to screen for, identify and synthesize EnAM phases after addition of additives to promote crystallization of desired phases. In collaboration with experimental investigations performed at the Leibniz Insitute for Materials Engineering we will perform high-throughput DFT calculations coupled with global-optimization methods for the unbiased determination of crystal structures. 

Supported by: DFG (SPP 2315)

Susan Köppen

Fibrious protein scaffolds are particularly attractive for various tissue engineering applications. However, to date it is not yet understood how specific protein-protein interactions and buffer conditions contribute to drive the fibrillogenesis of ECM proteins (such as fibronectin) or plasma proteins (such as fibrinogen). With a multiscale combination of closely connected simulative and experimental methods, we want to adress the underlying molecular mechanisms of fibrillogenesis with regard to environmental and molecular conditions. The project is a collaboration between the Hybrid Materials Interfaces group and the Biophysics and Applied Biophysics group at the Bremen University of Applied Sciences.

Supported by: DFG

Michael Fischer

Zeolites could find use in several applications that involve the adsorption of pharmaceutically active compounds and related organic species, for example in the removal of emerging contaminants from wastewaters or in drug delivery. Within this project, atomistic modelling methods are used to study the interaction of different functional organic molecules with various types of zeolites. On the one hand, these calculations have a predictive purpose, aiming to identify zeolite-guest combinations that could find use in applications. On the other hand, they will contribute to a better understanding of the interactions that govern the adsorption behaviour.

Supported by: DFG (Heisenberg programme)

Michael Fischer

A hierarchical, combined computational-experimental approach is used to study the adsorption of pharmaceuticals and personal care products (PPCPs) in hydrophobic all-silica zeolites. To start with, a large number of zeolite-PPCP combinations are investigated with force field simulations to identify combinations of particular interest. These combinations are then be studied with electronic structure methods, looking at various aspects like dominant interactions and adsorption-induced deformations. The role of guest-guest interactions is also explored. The computational parts are complemented by experimental studies for a few selected cases.

Supported by: DFG (Sachbeihilfe)

Tim Neudecker

Oriented external electric fields (OEEFs) have been used to catalyze a number of reactions by energetically favoring zwitterionic resonance structures in the transition state. Moreover, changes in geometries and dissociation energies of chemical bonds have been reported for molecules in OEEFs. In this project, using quantum chemical methods the mechanical behavior of molecules in OEEFs is investigated to establish new mechanochemical reaction pathways and develop functional materials like self-healing polymers.

Supported by: DFG

Tim Neudecker

Space radiation is one of the prime reasons why conditions outside of Earth’s atmosphere are inhospitable. However, space radiation could also be envisioned as a widely untapped additional energy resource that is readily available for harvesting and conversion into electrical energy. Using a combination of state-of-the-art material science, simulation and irradiation techniques, this project therefore aims at designing novel ceramic/polymer composite materials for protection from and energy harvesting of space radiation. The project is paving the way for the development of novel functional materials that use space radiation in ways that are beneficial both in extra-terrestrial environments and on Earth.

Supported by: APF and state of Bremen

Christoph Behrens / Vasily Ploshikhin

In Wire-Arc-Additive-Manufacturing the blank part consists of multiple weld tracks. When milled later, the final contour cannot be hit exactly because of welding deformations. The project aims to use numerical simulations to generate displacement-optimized CAD-Geometries.
For this purpose, an adapted inherent strain simulation is calibrated on a single multi-layer wall.  Displacements were successfully calculated for geometrically different 316L parts. The inverted deformation can be applied to the CAD. The contour of a printed displacement-optimized part is in close agreement with the desired end contour. Further validations are carried out.

Supported by: Bundesministerium für Wirtschaft und Klima

Hannes Birkhofer / Vasily Ploshikhin

The aim of the project is to develop calibrated simulation models for the rapid prediction of macro and micro temperature fields of additively manufactured metallic components in order to adapt process parameters locally. Within the scope of the project, optimization strategies of the AM process parameters are to be developed and verified on the basis of the specific component geometry as well as the process simulation results of the local melt pool and the entire build space. As a contribution to the research network, repair and exposure strategies will be developed in the project, which will enable defects that have arisen in the process to be healed with minimal influence on the defect environment.

Supported by: BMWK