Polyakov-Quark-Meson-Diquark Model for two-color QCD

We present an update on the phase diagram of two-color QCD from a chiral effective model approach based on a quark-meson-diquark model using the Functional Renormalization Group (FRG). We discuss the impact of perturbative UV contributions, the inclusion of gauge field dynamics via a phenomenological Polyakov loop potential, and the impact of matter backcoupling on the gauge sector. The corresponding phase diagram including these effects is found to be in qualitative agreement with recent lattice investigations.Comment: 8 pages, 9 figures; published versio

S4Sleep: Elucidating the design space of deep-learning-based sleep stage classification models

Scoring sleep stages in polysomnography recordings is a time-consuming task plagued by significant inter-rater variability. Therefore, it stands to benefit from the application of machine learning algorithms. While many algorithms have been proposed for this purpose, certain critical architectural decisions have not received systematic exploration. In this study, we meticulously investigate these design choices within the broad category of encoder-predictor architectures. We identify robust architectures applicable to both time series and spectrogram input representations. These architectures incorporate structured state space models as integral components, leading to statistically significant advancements in performance on the extensive SHHS dataset. These improvements are assessed through both statistical and systematic error estimations. We anticipate that the architectural insights gained from this study will not only prove valuable for future research in sleep staging but also hold relevance for other time series annotation tasks.Comment: 11 pages, 1 figure, code available at https://github.com/AI4HealthUOL/s4slee

Spectral Functions for the Quark-Meson Model Phase Diagram from the Functional Renormalization Group

We present a method to obtain spectral functions at finite temperature and density from the Functional Renormalization Group. Our method is based on a thermodynamically consistent truncation of the flow equations for 2-point functions with analytically continued frequency components in the originally Euclidean external momenta. For the uniqueness of this continuation at finite temperature we furthermore implement the physical Baym-Mermin boundary conditions. We demonstrate the feasibility of the method by calculating the mesonic spectral functions in the quark-meson model along the temperature axis of the phase diagram, and at finite quark chemical potential along the fixed-temperature line that crosses the critical endpoint of the model.Comment: 11 pages, 5 figures, 1 tabl