Tim-Leon Klocke

• Klocke, Tim-Leon (2026). Constraining Beyond-CDM Models with an Effective Theory of the Lyman-α Forest. doi: https:/indico.global/event/15863/contributions/156017/. Fulltekst i vitenarkiv Vis sammendrag

  In the age of precision cosmology, mapping the large-scale structure of the universe has the potential to reveal pieces of the puzzle that is the nature of dark matter. Most deviations from standard cold DM (CDM) models are confined to cosmologically small scales to not violate existing constraints. Thus, there is a fundamental need to have accurate models of the non-linear formation of structures in beyond-CDM models. Therefore, we present a framework in the spirit of the effective field theory of large-scale structure (EFTofLSS) describing observations of the Lyman-α forest and test its applicability to beyond-CDM models of DM. We focus on mixed Hot/Warm + Cold DM models, and present a systematic study of the statistical power of this effective approach, with the goal of quantifying its predictability regarding beyond-CDM models. Moreover, we discuss its applicability to observational data on the largest Lyman-α scales as measured by BOSS and DESI, and the possible challenges this entails.

• Klocke, Tim-Leon (2026). Constraining Beyond-CDM Models from Large-Scale Structures. doi: https:/indico2.uis.no/event/64/contributions/1998/. Fulltekst i vitenarkiv Vis sammendrag

  In the age of precision cosmology, mapping the large-scale structure (LSS) of the universe has the potential to reveal pieces of the puzzle describing the nature of dark matter. Most deviations from standard cold DM (CDM) models are confined to cosmologically small scales as possible signatures at very large scales are already excluded by precise measurements of the CMB. Thus, there is a fundamental need to have accurate models of the (non-linear) formation of structures in beyond-CDM models. To begin, a classification of the impact of different models on the LSS is needed, which enables us to systematically scan the most interesting parameter space. This can be used to evaluate the (quasi) non-linear evolution of structure formation, which is especially relevant for applications to Lyman-α data. To attain this goal, I will present a version of the effective field theory of large-scale structure (EFTofLSS), which enables faster scans than traditional simulation-based methods. Nevertheless, significant challenges remain in the statistical interpretation of any results obtained, because there are multiple astrophysical, theoretical assumptions and degeneracies, which have to be consistently taken into account. However, application of these methods to data has the potential to improve our current understanding of many existing bounds on beyond-CDM models.

• Klocke, Tim-Leon (2025). Constraining the Dark Sector with Cosmological Large-Scale Structure Observations. doi: https:/indico2.uis.no/event/59/contributions/1907/. Fulltekst i vitenarkiv Vis sammendrag

  Understanding the intersection of particle physics and cosmology – dark matter – is a crucial open question in physics and cosmology. Here the goal is to construct a pipeline in which the implications of different dark matter models – from their particle nature to cosmological observations of large-scale structure (LSS) – can be systematically studied. Specifically, studying the (late-time) evolution of structure using Lyman-α data and, moreover, derive constraints on the particle nature of dark matter and extended dark sectors. This requires the usage of large simulations, novel methods in the realm of effective field theory of large scale structure (EFTofLSS), as well as understanding observational limitations and constraints. I will provide an overview over the most important open questions and how we plan to tackle each of them.

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