We discuss quantum improvements of black holes in asymptotic safety scenario. In this scenario, the Newton coupling depends on an energy scale, which must then be identified with a certain length scale. Due to this “scale identification,” in a small scale, e.g., near the singularity, a quantum mechanically corrected or “quantum improved” geometry behaves significantly differently from its classical counterpart. For example, the quantum improved Schwarzschild black hole is perfectly regular near the center. However, when considering more general black holes, whether a singularity is resolved or not depends on the choice of possible scale identification. Furthermore, if applying the same scale identification as in the Schwarzschild case for a rotating black hole, the quantum improved rotating black hole becomes inconsistent with the thermodynamic laws. In this talk, we first briefly review quantum improvement of black holes in asymptotic safety scenario and the problem in possible choice of scale identifications. We then propose that the consistency with the first law of black hole thermodynamics is the guiding principle for a physically sensible choice of scale identifications. This principle leads us to show that the running Newton coupling should be a function of the horizon area at least near the horizon, and also to find a universal formula for the quantum entropy.

Some say that the high density EOS is only poorly constrained, but this statement is just like a pump and dump. If you look at the QCD calculations you may find huge uncertainty, but this uncertainty extends to the direction to make the EOS softer below the conformal bound that is already very soft. This implies an intriguing physics picture that interacting nuclear matter quickly approaches the conformal EOS and it is saturated by weakly interacting quark matter after smooth crossover where the speed of sound can have a peak. Such considerations lead us to a well constrained and very likely EOS with quark matter crossover. Then, the question is whether such a smooth change without the frequently-postulated first-order discontinuity can be detectable by the gravitational wave observation or not, and our recent analysis gives a positive answer.

ヘテロティック弦は10次元時空ですでに非可換ゲージ対称性を持つ超弦理論であり、80年代、現在のような宇宙観測結果もない時代に精力的に研究されました。しかしD-ブレインの認識以降、それを含まないヘテロティック理論は弦理論研究の主流ではなくなっていましたが、主要なGUTゲージ群や素粒子１世代SO(10)のスピナー表現物質を自然に導出するという性質は、現代の弦理論による模型構築においても大きな利点です。
中島さんには、現代的な視点から、このようなヘテロティック理論について、基本的なことから解説していただきたいと思います。

The Cold Dark Matter model for structure formation is currently the most successful at reproducing many observations, but it remains largely untested in the non-linear sub-galactic regime. A clear prediction of this model is that a significant number of low-mass haloes should populate any galaxy and its line of sight. As most of these objects are expected to be completely dark, strong gravitational lensing provides a unique channel to detect them and determine the properties of dark matter by constraining the halo-mass function at the low-mass end.

Ultralight dark matter (ULDM) is known to form self-gravitating bound states through gravitational relaxation. There are intriguing hints in the literature suggesting similar dynamics might lead to overdensities in the solar system as well, with ULDM becoming bound to the Sun. These *Solar Halos* can be probed by experiments on Earth when their radius *R > 1 AU*, which implies ULDM particle masses *m < 10^{-14} eV.* For larger masses *m*, space-based missions on orbits within 1 AU can probe small, compact Solar Halos with exceptional reach; for scalar couplings probable in current and near-future atomic clock systems, the sensitivity can exceed that of Equivalence Principle tests and probe well-motivated space for natural scalar field models. I will review the state of the art on these topics, including several exciting NASA and international space missions that motivate searches aboard space probes.

The Effective Field Theory of Large-Scale Structure is a perturbative formalism that allows us to predict the clustering of Cosmological Large-Scale Structure in the mildly non-linear regime in an accurate and reliable way. After a brief illustration of the theory, I will discuss recent results on its application to the analysis of galaxy clustering data.

We discuss new possible tunneling processes in the presence of gravity.
We formulate quantum tunneling using the Wheeler-deWitt canonical quantization and the WKB approximation. The distinctive feature of our formulation is that it accommodates the coexistence of Euclidean and Lorentzian evolution. It opens up a new possibility of quantum tunneling; {¥it e.g.} a bubble wall itself tunnels the potential barrier pulling the field nearby, where the wall region experiences the Euclidean evolution while the other regions experience the Lorentzian evolution simultaneously.
We execute numerical analysis and find that such a process can have a much higher tunneling rate than that of the Coleman-De Luccia bounce. We also find that the new tunneling processes exist even in the decoupling regime of gravity and affect low energy phenomenology.

Different Cosmologies for dark matter, or dark radiation, have different observational prospects. Standard Model particles were in thermal equilibrium at early times. But maybe the dark sector was not. In this talk I will discuss a few scenarios where particles are produced by non-equilibrium processes in the dark sector. I will show how dark matter, such as sterile neutrinos, could have been produced through an explosive period of exponential growth (similar to the spreading of a pathogen). I will also describe how radio photons can be produced by resonant oscillations of dark photons, as a possible explanation of the Arcade radio excess.

Because the axion is a pseudo-scalar Boson, as the interaction between axions and matter, spin-dependent interactions have been mainly discussed up to the present.
Spin-independent terms, which break the axion shift symmetry, are considered to be small, being suppressed by the axion mass.
However, we have found that couplings of 4-point interactions between nucleons and axions are not negligibly small.
The term is of particular importance for the axion dark matter, which has a long Compton length, because the scattering amplitude is enhanced by the coherent effect.
We discuss the consequences and the possible application of the interactions.

We study equilibrium transport properties of massless Dirac fermions at finite temperature and chemical potential in spacetime accompanied by torsion, which in four dimensions couples with Dirac fermions as an axial gauge field. In particular, we compute the current density at the linear order in the torsion as well as in an external magnetic field with the Pauli-Villars regularization, finding that an equilibrium current akin to the chiral magnetic current is locally induced.
Such torsion can be realized in condensed matter systems along a screw dislocation line, around which localized and extended current distributions are predicted so as to be relevant to Dirac and Weyl semimetals.
Furthermore, we compute the current density at the linear order in the torsion as well as in a Weyl node separation, which turns out to vanish in spite of being allowed from the symmetry perspective.