We evaluate the phase diagram of quantum gravity within a fully diffeomorphism-invariant renormalisation group approach. The construction is based on the geometrical or Vilkovisky-DeWitt effective action. We also resolve the difference between the fluctuation metric and the background metric. This allows for fully background-independent flows in gravity.The results provide further evidence for the ultraviolet fixed point scenario in quantum gravity with quantitative changes for the fixed point physics. We also find a stable infrared fixed point related to classical Einstein gravity. Implications and possible extensions are discussed.

We analysed how teachers as users of open educational resources (OER) repositories act in the re-use process and how they perceive quality. Based on a quantitative empirical study, we also surveyed which quality requirements users have and how they would contribute to the quality process. Trust in resources, organizations, and technologies seem to be of particular importance when looking at quality. In our findings, we derive recommendations for learning object repositories and OER user-oriented quality assurance.

Abstract

We put forward a continuum approach for computing finite temperature correlation functions in Yang-Mills theory. This is done in a functional renormalisation group setting which allows for the construction of purely thermal RG-flows. This approach is applied to the ghost and gluon propagators as well as the ghost-gluon vertex in the Landau gauge. We present results in a temperature regime going from vanishing temperature to temperatures far above the confinement-deconfinement temperature Tc. Our findings compare well with the lattice results available.

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Global software development (GSD) holds various challenges and problems for team members. When confronted with a contextual change in their working environment, individuals have to adapt to the new situation. This includes the adaptation of working styles, behaviors, and methods. Additionally, new challenges, especially those based on the virtual work and cultural background of team members, have to be addressed. By conducting explorative expert interviews, we identified challenges and potential solutions for individuals when encountering contextual change with a focus on competences. We identified that the lack of competences was seen as a major influence factor for a variety of common challenges to GSD. The identification of underlying factors of challenges could allow for focused development of interventions to overcome these challenges. Furthermore, we identified factors influencing the adaptation of competences to the given context and provided insight into the process of competences adaptation. This is the basis for the future development of a set of internationalized GSD competences.

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We present the first direct and non-perturbative computation of the graviton spectral function in quantum gravity. This is achieved with the help of a novel Lorentzian renormalisation group approach, combined with a spectral representation of correlation functions. We find a positive graviton spectral function, showing a massless one-graviton peak and a multi-graviton continuum with an asymptotically safe scaling for large spectral values. We also study the impact of a cosmological constant. Further steps to investigate scattering processes and unitarity in asymptotically safe quantum gravity are indicated.