Description
Very short talks before lunch intended to spur discussion.
Future space-based laser interferometry experiments such as LISA are expected to detect $\mathcal{O}(100-1000)$ stellar-mass compact objects (e.g., black holes, neutron stars) falling into massive black holes in the centers of galaxies, the so-called extreme-mass-ratio inspirals (EMRIs). If dark matter forms a "spike" due to the growth of the massive black hole, it will induce a gravitational...
Axion-like particles (ALP) are appealing candidates for dark matter if produced non-thermally via the vacuum misalignment mechanism. In certain cases, such as in the presence of a monodromy, the self-interactions of ALPs can be sufficiently strong and lead to the fragmentation of the homogeneous field soon after the onset of oscillations. We investigate numerically the dynamics of...
We show that gravitational wave emission from neutron star binaries can be used to discover ultra-light U(1)$_{L_\mu-L_\tau}$ vectors by making use of the large inevitable abundance of muons inside neutron stars. In pulsar binaries the U(1)$_{L_\mu-L_\tau}$ vectors induce an anomalously fast decay of the orbital period through the emission of dipole radiation. We study a range of different...
Conventional approaches to probing axions and axion-like particles (ALPs) typically rely on a coupling to photons. However, if this coupling is extremely weak, ALPs become invisible and are effectively decoupled from the Standard Model. We show that such invisible axions, which are viable candidates for dark matter, can produce a stochastic gravitational wave background in the...
Extended scalar sectors often emerge in models motivated by the electroweak hierarchy problem. In particular, the scalar triplet extension of the SM is interesting because the triplet decay is very constrained at the renormalizable level. Therefore, effective operators with a low cutoff make the triplet components decay promptly, leading to a drastically different collider phenomenology. In...
We explore gravitational wave signals arising from first-order phase transitions occurring in a secluded hidden sector, allowing for the possibility that the hidden sector may have a different temperature than the Standard Model sector. Secluded hidden sectors are of particular interest for dark matter models at the MeV scale or below, which falls into the sensitivity range of pulsar timing...
The North American Nanohertz Observatory for
Gravitational Waves (NANOGrav) has recently released its
12.5 year data set. I will summarize the GW results and their
implications for limits on Supermassive Black Hole Binaries
through hierarchical galaxy merging. These limits are starting
to substantially constrain models for SMBHB. We anticipate
detection of the stochastic background of...
We will review gravitational wave propagation in standard and non-standard cosmological history. Particularly, we will discuss the spectrum of primordial gravitational (PWG) waves spectrum induced due to inflation in such scenarios. Then we will show the predictions in scenarios as predicted by various modified gravity theories, motivated by beyond ΛCDM model of cosmology and dark energy...
