During the accretion phase of a core-collapse supernova (SN), dark-photon (DP) cooling can be largest in the gain layer below the stalled shock wave. In this way, it could counteract the usual shock rejuvenation by neutrino energy deposition and thus prevent the explosion. This peculiar energy-loss profile derives from the resonant nature of DP production. The largest cooling and thus...
Many low-mass dark matter experiments focus on highly segmented detectors with low particle detection thresholds. For these situations in particular, the neutron capture process is important to consider for direct low-energy calibrations and a possible background source. I will summarize the effect of this process on dark matter searches, specifically focusing on the SuperCDMS collaboration...
We propose a novel mechanism to detect terrestrial cosmic neutrino background’s (CNB) limit of electric charge by employing Mach-Zehnder interferometer with asymmetrical arm placement – one at the Earth’s surface and the other is placed underground. Assuming that relic neutrinos possess a small but nonzero charge, their coherent forward scattering with photons induces measurable phase shift in...
In this talk I will briefly introduce some previous researches I have gone through on the topic of self-interacting dark matter (SIDM). For particle aspect, I will review the inclusion of SIDM, the enhancement of potential DM accumulating in the core of stellar objects and its potential observations. For astrophysical aspect, I will introduce the properties of exotic stellar objects...
The detection of cosmic antideuterons at kinetic energies below a few GeV/n could provide a smoking gun signature for dark matter (DM). However, the theoretical uncertainties arising from the choice of coalescence models were so far one of the main limiting factors for precise predictions of the $\overline{\rm D}$ flux. In this talk, we present a novel calculation of the $\overline{\rm D}$...
In current concordance cosmological model, Lambda-CDM model, we are facing serious cosmic tensions, such as Hubble tension, S_8 tension, dipole tension, etc. These problems challenge the basic assumption of cosmology, cosmological principle. In this talk, I will show how a local structure, a Gpc-scale void, impacts our understanding on Hubble tension, S_8 tension, and dipole tension, and a...
In recent years, the holographic duality between $T\bar{T}$-deformed conformal field theory (CFT) and Anti-de Sitter (AdS) spacetime with finite radial cutoff has received significant attention. The study of $T\bar{T}$ deformation within the framework of de Sitter (dS)/CFT duality has also progressed. In this talk, we generalize the replica method in both AdS and dS holography to derive a...
I report the latest results of our group for the new mass ranges of primordial black hole to be dark matter if we seriously consider the memory burden effect.
We formulate the statistics of peaks of non-Gaussian random fields and implement it to study the sphericity of peaks. For non-Gaussianity of the local type, we present a general formalism valid regardless of how large the deviation from Gaussian statistics is. For general types of non-Gaussianity, we provide a framework that applies to any system with a given power spectrum and the...
We study the analogy between graviton emission and absorption in a thermal radiation environment and the laser mechanism, in which photons of the same momentum and polarization are amplified. Using interaction-picture perturbation theory, we analyze the time evolution of the graviton number operator and its expectation value in a squeezed vacuum state, which characterizes the inflationary...
Primordial gravitational waves (GWs), beyond their direct detection prospects, can induce second-order scalar perturbations. These tensor-induced scalar modes evolve similarly to standard matter perturbations and leave distinct imprints on the large-scale structure (LSS). In this talk, I will present a detailed study of these effects, including analytical results for the evolution of induced...
We present a minimal setup within the framework of Horndeski gravity that can describe a nonpathological Genesis scenario. Our setup allows for a fully stable transition to the kination epoch, during which General Relativity (GR) is restored. This Genesis scenario circumvents the no-go theorem at the cost of encountering the risk of strong coupling in the past. Interestingly, our scenario...
Recent 2σ–4σ deviations from the cosmological constant $\Lambda$ suggest that dark energy (DE) may be dynamical, based on baryon acoustic oscillations and full-shape galaxy clustering analyses. This calls for even tighter DE constraints to narrow down its true nature. In this talk, I present how galaxy intrinsic alignments (IA) can enhance the full-shape galaxy clustering–based DE constraints,...
The near luminality and non-decay of Gravitational Waves (GWs) has ruled out all quartic and quintic Beyond Horndeski theories with a minimally coupled photon. In this talk, I show that --- with specific couplings between the scalar and the photon --- one can ensure luminal GWs and their suppressed decay in at least one viable Beyond Horndeski theory. I also discuss extensions of these...
Gravitational waves emitted from binary black hole mergers exhibit highly distinctive characteristics. When these waves undergo gravitational lensing, the resulting distortions in amplitude and phase can be identified. This phenomenon can thus be leveraged to probe small-scale dark matter structures that may have originated in the early universe. In this talk, I will discuss recent advances in...
I will present our results on how to possibly discriminate equations of state with a quark-hadron crossover with respect to equations of state with purely hadronic matter or with a first-order quark-hadron transition through gravitational waves emitted in binary neutron star mergers.
