Conveners
Parallel VI: Cosmology
- Shinji Tsujikawa (Tokyo University of Science)
Parallel VI: Cosmology
- Shinji Tsujikawa (Tokyo University of Science)
Conventional wisdom relates the vacuum energy arising from the zero point fluctuations of quantum fields with the cosmological constant which is a parameter in Eidnstien's field equations. The basis of this relation is in the semi-classical approximation where gravity is treated classically. However, as is well known, the effective cosmological constant generated by the zero-point...
Observational evidence for the existence of Dark Matter is limited to its gravitational effects. The extensive program for dedicated searches has yielded null results so far, challenging the most popular models. Here we propose that this is the case because the very existence of cold Dark Matter is a manifestation of gravity itself. Indeed, the only known ghost-free extension of General...
WIMP Dark Matter generally assumes the Standard Model and Dark Matter form a single thermal bath at early time, with the Dark Matter relic density set by interactions between these two populations. Arguably, a more compelling assumption is that Dark Matter is not part of the Standard Model sector. Even if there are decoupled dark sectors, then it is a natural expectation that the visible and...
It has been shown that gravitational waves propagate through ideal fluids without experiencing any dispersion or dissipation. However, if the medium has a non-zero shear viscosity, gravitational waves will be dissipated at a rate proportional to Gη?. We test Dark Matter and Dark Energy models with non-zero shear viscosity by calculating the dissipation of GW150914 which propagates over a...
We analyze constraints on parameters characterizing the pre-inflating universe in an open inflation model with a present slightly open $\Lambda_{\rm CDM}$ universe. We employ an analytic model to show that for a broad class of inflation-generating effective potentials, the simple requirement that some fraction of the observed dipole moment represents a pre-inflation isocurvature fluctuation...
Under general circumstances, the Standard Model Higgs is excited in the form of a condensate during or towards the end of inflation. The Higgs condensate is then forced to decay afterwards — due to non-perturbative effects — into the rest of the SM species. I will present the cosmological implications of this primordial decay, quantifying the necessary conditions to achieve a successful...
Partially based on Phys.Rev.Lett. 115 (2015) no.18, 181104, in collaboration with Sourav Bhattacharya, Konstantinos F. Dialektopoulos, Antonio Enea Romano, Theodore N. Tomaras.
Based on an article Published in Phys.Lett. B755 (2016) 464-468, in collaboration with Prof Misao Sasaki. director of the Yukawa Institute for Theoretical Physics(YITP), in Kyoto , Japan.
The observed Higgs mass indicates that its quartic coupling and beta function (and also bare mass) can simultaneously vanish around the Planck scale. Such a non-trivial behavior of the Higgs potential is called the criticality of the Standard Model. Here, we show that it can be explained based on the Coleman’s multi-local theory.
