New Directions in Cosmology

Session

Short talks

24 Mar 2020, 14:00

Faculty of Science Bldg. 1 East: Room 285 (Hongo Campus)

11. TBA

So Chigusa (University of Tokyo)

24/03/2020, 14:00

47. To B or not to B: Primordial magnetic fields from Weyl anomaly and Beyond

Takeshi Kobayashi (Kobayashi-Maskawa Institute for the Origin of Particles and the Universe, Nagoya University)

24/03/2020, 14:25

For more than twenty years, it has been argued that the Weyl anomaly of quantum electrodynamics sources cosmological magnetic fields in the early universe. If true, this would be a natural way to produce the seed magnetic fields of our universe within the Standard Model. In this talk, I will examine this long-standing claim and show that there is actually no production of coherent magnetic...

48. Primordial magnetic fields and 21-cm line observation

Teppei Minoda (Nagoya University)

24/03/2020, 14:50

The primordial magnetic fields (PMFs) are expected to be generated in the early universe, and they are a possible origin of the present galactic magnetic fields. In this talk, we suggest a novel method to investigate the PMFs with 21-cm line observation. The recent observation of the 21-cm global absorption signal by EDGES suggests that the intergalactic medium (IGM) gas has been cooler than...

12. On the magnetogenesis and baryogenesis at the electroweak cross over

Kohei Kamada (RESCEU, U-Tokyo)

24/03/2020, 15:45

It has been found that baryon asymmetry of the Universe (BAU) can be generated without introducing any new physical ingredients beyond the Standard Model (SM) from the chiral asymmetry of the SM, if there exist helical hypermagnetic fields before the electroweak symmetry breaking. Then in order to explain the BAU, we need the physics beyond the SM to generate large-scale hypermagnetic fields....

13. Baryogenesis from axion inflation

Kyohei Mukaida (DESY)

24/03/2020, 16:10

The coupling of an axion-like particle driving inflation to the Standard Model (SM) particle content through a Chern-Simons term generally sources a dual production of massless helical gauge fields and chiral fermions. We demonstrate that the interplay of these two components results in a highly predictive baryogenesis model, which requires no further ingredients beyond the Standard Model. If...

15. Curvature fluctuations from disorder during inflation

Marcos Garcia Garcia (IFT-UAM)

24/03/2020, 17:05

Although it is commonly assumed that the physics of inflation and the subsequent reheating epoch can be understood by means of simple effective field theories, there is no guarantee that this reductionist point of view is realized. In fact, some UV completions of inflation tend to involve many fields, with complicated interactions that can lead to significant elements of randomness in the...

16. Big Bounce Baryogenesis

Neil Barrie (Kavli IPMU)

24/03/2020, 17:30

We explore the possibility of an Ekpyrotic phase induced by a fast rolling pseudoscalar field prior to a non-singular bounce harbouring a mechanism for Baryogenesis. Chern-Simons couplings to the Standard Model Hypercharge and Weak gauge fields enable the generation of a non-zero Chern-Simons number density during the contracting phase. The resulting baryon number produced is found to be...

23. Higgs inflation, unitarity, and emergence of scalaron

Yohei Ema (DESY)

25/03/2020, 14:00

The vanilla Higgs inflation introduces a large non-minimal coupling between the Ricci scalar and Higgs that causes the tree-level unitarity violation well below the Planck scale. After reviewing the unitarity issue of the Higgs inflation during and after inflation, we show that the unitarity can be restored by summing over vacuum polarization-type diagrams. The scattering amplitude develops a...

49. Inflation and Preheating in the Mixed Higgs-R^2 Model

Minxi He (RESCEU, UTokyo)

25/03/2020, 14:25

We consider the inflation and preheating process in a two-field model which consists of the R^2 term in the Starobinsky model and standard model Higgs field with non-minimal coupling. The inflation dynamics is found to be effectively single-filed like with large non-minimal coupling. The (p)reheating process presents different properties from those in single-field models. The violent behavior...

50. Entropy Production in Affine Inflation

Hemza Azri (Koç University, Istanbul)

25/03/2020, 14:50

Multiple scalar fields nonminimally interacting through pure affine gravity are considered to generate primordial perturbations during an inflationary phase. The couplings considered give rise to two distinct sources of entropy perturbations that may not be suppressed in the long wavelength limit. The first is merely induced by the presence of more than one scalar and arises even in the...

25. Solving the Hubble tension with Self Interacting Dirac Neutrino

Jiaming Zheng (Shanghai Jiaotong University)

25/03/2020, 15:45

In this talk I will show that a simple model of Dirac neutrinos that self-interact only through their right-handed components can naturally realize the self-interacting neutrino solution of the Hubble tension while evading all the cosmological or laboratory bounds.

26. The effect of Hawking radiation on blackhole catalyzed phase transition

Takumi Hayashi (RESCEU Tokyo University)

25/03/2020, 16:10

It has been discussed by Gregory et al. that small blackholes would catalyze vacuum phase transitions. We investigate such phase transition including the (inhomogeneous) thermal effect of Hawking radiation and calculate the bounce action numerically. I will show that the transition rate can be slightly suppressed by the thermal effect of Hawking radiation. I will also mention an application to...

27. Grand Unification of a simple extension of Minimal Dark Matter and collider signatures

Kana Hayami (Ochanomizu University)

25/03/2020, 17:05

The Minimal Dark Matter (MDM) model suggested by Cirelli et al. is an extended model that introduces one SU (2) _L multiplet to the Standard Model so that the neutral component of the multiplet plays as the role of dark matter (DM). On the other hand, the stability of DM is not guaranteed because there is no mechanism to inhibit the DM decay process. We have built a model that makes DM...

28. TBA

Shih-Yen Tseng (The University of Tokyo)

25/03/2020, 17:30

39. Observational constraint on interacting Tsallis holographic dark energy in logarithmic Brans-Dicke theory

Sanjay Mandal (Birla Institute of Technology and Science-Pilani, Hyderabad Campus)

26/03/2020, 14:00

In this paper, we investigate the dark energy phenomenon by studying the Tsallis holographic dark energy within the framework of Brans–Dicke (BD) scalar–tensor theory of gravity (Brans and Dicke in Phys. Rev. 124:925, 1961). In this context, we choose the BD scalar field ϕ as a logarithmic function of the average scale factor a(t) and Hubble horizon as the IR cutoff ( L=H^{−1} ). We...

51. Stability of two fluid dark energy cosmological model with diagnostic analysis

Bivudutta Mishra (BITS-Pilani, Hyderabad Campus)

26/03/2020, 14:25

In this paper, the stability analysis of an anisotropic dark energy cosmological model in a two fluid situations has been investigated. We have assumed that the dark energy pressure to be anisotropic in different spatial directions. several diagnostic analysis such as Om diagnostic, state finder analysis has also been incorporated and analysed. The results obtained are in accordance with the...

41. Aspects of Nonlinear Effect on Black Hole Superradiance

Hajime Fukuda (LBL)

26/03/2020, 15:45

Under some conditions, light boson fields grow exponentially around a rotating black hole, called the superradiance instability. We discuss effects of nonlinear interactions of the boson on the instability. In particular, we focus on the effect of the particle production and show that the growth of the boson cloud may be saturated much before the black hole spin is extracted by the boson...

42. Gravitational waves as a probe of small-scales: (Integrated) Sachs-Wolfe effect and spectral deformation

Ryusuke Jinno (DESY)

26/03/2020, 16:10

Gravitational waves (GWs) can be a sensitive probe of the early Universe dynamics. Once GWs are produced in the very early Universe (from whatever the source), their frequency and amplitude are affected by the density fluctuations on the way of their propagation. We point out that this effect, known as (Integrated) Sachs-Wolfe effect in CMB physics, appears as the deformation of the original...

43. Probes of Dark Matter at LIGO and Beyond

Sunghoon Jung (Seoul National University)

26/03/2020, 17:05

We discuss probes of dark matter with chirping GWs. The example dark matter candidates include primordial black holes and axion-like particles. We first discuss lensing observables of primordial black holes: GW fringes and GRB lensing parallax. They finally allow probing a whole range of the PBH mass range with lensing. Then we discuss the disturbance due to dark matter waves in the...

44. Reconsideration of leptogenesis via circularly polarized gravitational waves

Jun'ya Kume (RESCEU, UTokyo)

26/03/2020, 17:30

We revisit the gravitational leptogenesis scenario in which the lepton asymmetry is generated by circularly polarized gravitational waves during inflation, through the gravitational anomaly in the lepton number current. We consider a specific model in which the inflaton is coupled to gravity by the Chern-Simons term, and constrain the possible model parameter space by requiring the absence of...

52. Dark matter and dark energy in f(R): A unified approach

Murli Verma (University of Lucknow)

I will talk about the possibility of explaining both dark matter and dark energy in a single unified scalar field field matrix. This degree of freedom is also shown to interact with other matter (vector and fermioinic)fields to give rise to subtle effects in atomic spectroscopy. The observational features would also be discussed in detail.

29. Short talk 14

40. Short talk 16

45. Short talk 21

14. Short talk 4

17. Short talk 7

24. Short talk 9