EPJ Plus Focus Point Issue: Focus Point on Higher Derivatives in Quantum Gravity: Theory, Tests, Phenomenology
- Published on 07 April 2022
The quantization of General Relativity via standard perturbative quantum field theory results in a quantum theory of gravity which is perturbatively non-renormalizable. This caused a proliferation of approaches to quantum gravity, based on different assumptions, ideas, and quantization methods. However, within many of these approaches the Einstein-Hilbert action is expected to be complemented by higher-derivative operators. In the framework of quadratic gravity, these higher-order terms are crucial to make gravity renormalizable and asymptotically free; in string theory infinitely many of these arise in the form of “corrections”; in non-local gravity infinitely many derivatives are introduced at the level of the bare action to achieve both renormalizability and perturbative unitarity; in asymptotically safe gravity and in the spin-foam approach to quantum gravity a similar structure is expected to emerge at the level of the quantum effective action. Higher derivatives are also key in the framework of effective field theory, whose results ought to be matched by all approaches to quantum gravity. Last but not least, higher derivatives could impact the phenomenology of black holes, the wave form of gravitational waves, and the early-universe cosmology.
EPJ Plus Focus Point Issue: Citizen science for physics: From Education and Outreach to Crowdsourcing fundamental research
- Published on 31 January 2022
Citizen Science encompasses a broad range of activities, from science education and outreach to the actual harnessing of crowdsourcing to conduct state-of-the-art research in all sciences.
The present focus point is intended as both a review and advancement of current and future such activities in the field of core physics and related disciplines, as covered in the journal’s aims-and-scope. In particular, this article collection wishes to thoroughly explore - and act as incentive to foster - the contribution of citizen science to advancing science and how to design ongoing and future research projects to this aim.
EPJ Plus Focus Point Issue: Breakthrough optics- and complex systems-based technologies of modulation of drainage and clearing functions of the brain
- Published on 15 May 2020
Aims and Goals
There is intensive grow body of evidance that the lymphatics plays an crucial role in the keeping the health of the central nervous system (CNS) via the drainage of CNS tissues and clearance of metabolites and neurotoxins. The ability to stimulate the lymph flow in the sleeping brain is likely to play an important role in developing innovative methods in neurorehabilitation therapy. However, the scanty information available about the mechanisms of lymphatic clearance of waste products and toxins from the brain slows down progress in the appearance of technologies for therapeutic modulations of the lymphatics in the CNS.
This special issue is focused on the development and application of modern approaches from photonics and complex systems science to design promising strategies in stimulation of the cerebral lymphatics and development of breakthrough technologies for non-invasive and real time analysis of brain drainage and clearing functions. We strongly believe that this pioneering step will motivate researchers and industrial parners to create the novel promising devices for neurorehabilitaion medicine based on the stimulation of cerebral lymphatic functions.