Light dark matter candidates, such as axions and hidden photons, call for new ideas in direct detection. I discuss the recently proposed strategy of searching for e.g. axions using tunable cryogenic plasmas. The plasma haloscope enables resonant conversion by matching the axion mass to a plasma frequency, therefore converting axions to plasmons. Metamaterials are promising candidates, as the plasma frequency can be tuned. Besides axions, other dark matter candidates, such as hidden photons and scalars, can be successfully targeted with a plasma haloscope.

Langevin equation, Markovian process, multiplicative noise, Fokker-Planck equation, Schwinger-Keldysh formalism and much more... During this seminar, almost organised as a lecture, you will embark on a journey into the world of stochastic processes, with focus on their applications in the early Universe in the context of so-called stochastic inflation. We will begin by discussing how stochasticity emerges from the coarse-graining procedure, necessary to describe the effective dynamics of the largest cosmological scales that are affected by the quantum nature of the small-scale fluctuations.

Upcoming Large-Scale Structure surveys will likely become the next leading sources of cosmological information, making it crucial to have a precise understanding of the influence of baryons on cosmological observables. The Effective Field Theory of Large-Scale Structure (EFTofLSS) provides a consistent way to predict the clustering of dark matter and baryons on large scales, where their leading corrections in perturbation theory are given by a simple and calculable functional form even after the onset of baryonic processes.

Departures of inflation from the single-field slow-roll paradigm, also known as “features”, are common in ultraviolet completions of inflation. These departures can be significant at small scales where Cosmic Microwave Background data is not constraining. I will explain how such features during inflation can be tested through their gravitational wave signal. In particular, I will show that features lead to a characteristic oscillation in the stochastic gravitational wave background.

The open question of whether a black hole can become tidally deformed by an external gravitational field has profound implications for fundamental physics, astrophysics and gravitational-wave astronomy. Love tensors characterize the tidal deformability of compact objects such as astrophysical (Kerr) black holes under an external static tidal field. We prove that all Love tensors vanish identically for a Kerr black hole in the nonspinning limit or for an axisymmetric tidal perturbation. In contrast to this result, we show that Love tensors are generically nonzero for a spinning black hole.