In the universal framework of simplified t-channel dark matter models, the relic abundance is dominated by mediator annihilation in most of parameter space, which gets considerably enhanced by the Sommerfeld effect and bound state formation. We provide an intuitive and easy to use add-on package to micrOMEGAs, allowing for an automated inclusion of these effects for a generic t-channel dark...
We study the kinetic mixing between the cosmic microwave background (CMB) photon and the birefringent dark photon. These birefringent dark photon may exist in parity-violating dark sector, for example, through the coupling to axion field. We show that the birefringence of the dark photon propagates to the CMB photon, but the resulting birefringence may not be isotropic over the sky, but will...
It is well known that clouds of ultralight particles surrounding black holes produced by the superradiant instability can experience Landau-Zehner transitions if the black hole is part of a binary system.
We study the effect of orbital eccentricity, backreaction of the cloud onto it and observational possibilities with future gravitational-wave detectors like the Laser Interferometer Space...
We study Dark Matter production during first order phase transitions from bubble-plasma collisions. We focus on scenarios where the Dark Matter sector is secluded and its interaction with the visible sector (including the Standard Model) originates from dimension-five and dimension-six operators. We find that such DM is generally heavy and has a large initial velocity, leading to the...
Weak lensing offers a way to directly probe the matter distribution that is sensitive to the physics of the dark universe, in particular dark matter and dark energy. Since weak lensing is a projected effect, it is not possible to fully recover the time evolution of the density field. Tomography is crucial to recover this evolution for disentangling physical effects. The one-point probability...
Gravitational waves (GWs) present a promising avenue to probe the physics of inflationary reheating, which may play a crucial role in the thermal history of the early Universe. In this talk, I will discuss the unavoidable sources of GWs from graviton production during reheating. The processes under consideration include: $(i)$ $1 \to 3$ graviton Bremsstrahlung, $(ii)$ $2 \to 2$ scattering of...
It is well known that spontaneous breaking of discrete symmetries produce topological objects called domain walls, which must decay in order not to dominate the energy density of the universe. One of the possible decay scenarios is nucleating holes bounded by cosmic strings on the walls. Once they are nucleated, the holes expand faster and faster by eating the energy of the domain walls and...
We show that heavy axion domain walls induce domain walls of the QCD axion through a mixing between the heavy axion and the QCD axion, even when the pre-inflationary initial condition is assumed for the QCD axion. The induced domain walls arise because the effective $\theta$ parameter changes across heavy axion domain walls, shifting the potential minimum of the QCD axion. When the heavy axion...
In this talk, I will discuss the effect of low cosmic string tensions on the associated stochastic gravitational wave background. I will show that the gravitational wave spectrum is qualitatively different from the one produced by cosmic strings with larger tensions. In fact, it exhibits a very distinct oscillatory feature with dips in the amplitude at multiples of the frequency of the first...
This talk focuses on gravitational-wave backgrounds (GWB) from cosmic strings that would manifest only at ultra-high frequencies (above kilohertz), that leave no signal at either LIGO, Einstein Telescope, or LISA, and correspond to high-energy scale (beyond $10^{10}$ GeV) particle physics parameters. Signals from metastable local strings, with amplitude as large as the $\Delta N_{\rm eff}$...
We study for the first time the gravitational waves generated during the collapse of domain walls, incorporating the potential bias in the lattice simulations. The final stages of domain wall collapse are crucial for the production of gravitational waves but have remained unexplored due to computational difficulties. As a significant application of this new result, we show that the observed...
The gauge “slingshot” effect occurs when a source, such as a quark or a magnetic monopole, crosses the boundary between the Coulomb and confining phases during a first-order phase transition. The corresponding gauge field of the source, either electric or magnetic, gets confined into a flux tube stretching in the form of a string (cosmic or a QCD type) that attaches the source to the domain...
The electroweak hierarchy problem is often a source of controversy – do we need to care about the Higgs curvature parameter $\mu^2$ being tuned to a small value, against quantum field theoretical expectation?
We explore the possibility that $\mu^2$ is initially large – as expected when introducing physics beyond the standard model – and is dynamically tuned to its current value at zero...
Gravitational Waves (GWs) can alter the neutrino propagation distance and thus affect neutrino oscillations. This can result in a complete disappearance of the oscillatory behavior that competes with other sources of neutrino decoherence. We develop a set of criteria that determines under which conditions neutrino oscillations are sensitive to this effect, and discuss three concrete scenarios...
