Conveners
Beyond V
- Shinji Mukohyama (morning)
- Alexander Vikman (afternoon)
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Prof. Alexander Vikman05/07/2019, 08:45
I will start by reviewing the mimetic formulation for irrotational fluid-like Dark Matter. It turned out that the latter can be described by a Weyl-invariant higher-derivative scalar-tensor theory beyond the Horndeski class of theories. Then I will proceed by discussing a novel vector extension of the mimetic construction. This novel vector-tensor theory provides a Weyl-invariant...
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Leonardo Modesto (SUSTech)05/07/2019, 09:30contributed talk
We present a weakly nonlocal gravitational theory unitary and finite at quantum level in the quantum field theory framework. As a consequence of finiteness, there is no Weyl anomaly and the theory turns out to be conformal invariant at classical as well at quantum level. Therefore, nonlocal quantum gravity is a conformal invariant theory in the spontaneously broken phase of the Weyl symmetry....
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Katsuki Aoki (Yukawa Institute for Theoretical Physics, Kyoto University)05/07/2019, 09:50contributed talk
We discuss scalar-tensor theories based on a non-Riemannian geometry, called the metric-affine geometry, where the metric and the connection are treated as independent variables. In the metric-affine formalism, the Einstein-Hilbert action enjoys an additional local symmetry, the projective symmetry, under a shift of the connection. We find that the projective symmetry can provide an...
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Prof. Marcus Werner (YITP, Kyoto University)05/07/2019, 10:40
Optical geometry is a spatial formalism for light propagation in Lorentzian spacetimes. This provides a geometrically interesting and useful framework for gravitational lensing, which is usually treated in terms of the quasi-Euclidean standard approximation instead. In this talk, I will first consider Riemannian optical geometry, and review basic results as well as recent work using the...
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Prof. Emanuela Dimastrogiovanni05/07/2019, 11:25
I discuss the prospects for constraining gravitational waves from non-minimal inflationary models using: (i) the large scale structure, through the so-called "fossil" signatures; (ii) cross-correlations of tracers of the large scale structure with secondary CMB anisotropies from kinetic and polarized Sunyaev–Zel'dovich effects. I show how these different routes for testing primordial...
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Prof. Atsushi Naruko05/07/2019, 12:10contributed talk
In this talk, we show that there is a class of spacetime curvature singularities which can be resolved with metric and matter field transformations. As an example, we consider an anisotropic power-law inflation model with gauge and scalar fields in which a space-like curvature singularity exists at the beginning of time. First, we provide a transformation of the metric to the flat geometry....
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Antonino Marciano (Fudan University)05/07/2019, 14:00contributed talk
We discuss how inflation can emerge from a four-fermion interaction induced by torsion. Inflation can arise from coupling torsion to Standard Model fermions, without any need of introducing new scalar particles beyond the Standard Model. Within this picture, the inflaton field can be a composite field of the SM-particles and arises from a Nambu-Jona-Lasinio mechanism in curved space-time,...
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Mr Jérémy Auffinger (Institut d'Astrophysique de Paris)05/07/2019, 14:20contributed talk
Primordial Black Holes (PBHs) are appealing candidates for dark matter in the universe but are severely constrained by theoretical and observational constraints. I will focus on the Hawking evaporation limits extended to Kerr Black Holes. These results have been obtained with a new to-be-published code entitled BlackHawk that I will briefly present. In particular, I will review the isotropic...
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Michael Seifert (Connecticut College)05/07/2019, 14:40contributed talk
Many classical field models which "violate Lorentz symmetry" do so via a vector or tensor field which takes on a vacuum expectation value, thereby spontaneously breaking the underlying Lorentz symmetry of the Lagrangian. To obtain a tensor field with this behavior, one can posit a smooth potential for this field, or one can enforce a non-zero tensor value via a Lagrange multiplier. In this...
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Prof. Shinji Mukohyama05/07/2019, 15:00
It is generally believed that modification of GR inevitably introduce extra physical degree(s) of freedom. In this talk I argue that this is not the case by constructing modified gravity theories with two local physical degrees of freedom. After classifying such theories into two types, I show explicit examples and discuss their cosmology and phenomenology.
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Ding-Fang Zeng05/07/2019, 15:50contributed talk
We will discuss in our talk a picture for blackholes' inner structure and microscopic state in which matters falling into the horizon or consisting of them are oscillating around instead of accumulating statically on their central point, thus resolving the Schwarzschild singularity naturally. After quantizing, this picture not only blurs the horizon remarkably, but also provides an...
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Matthew Talia (University of Sydney)05/07/2019, 16:10contributed talk
The presence of a large, non-vanishing background charge in the universe can interestingly have implications on symmetry restoration at high temperature. In theories with continuous global symmetries, like the R-symmetry of the MSSM, these can lead to important cosmological effects seemingly independent of the short-distance scale physics. Here we explore the effect of temporary R-symmetry...
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Da Huang (University of Warsaw)05/07/2019, 16:30Poster session
We connect the electroweak (EW) baryogenesis and the dark matter physics in a complex singlet scalar S extension of the Standard Model. We impose the additional CP and Z_2 symmetries on the scalar potential. With the complex vacuum expectation value of S at the temperature higher than the EW phase transition, the CP symmetry is spontaneously broken and a strong first-order EW phase transition...
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Jerzy Krol (University of Silesia)05/07/2019, 16:50Poster session
Smooth QG is the attempt to use findings and infinite geometric constructions of differential geometry and topology in dimensions 3 and 4, to solve problems in physics, especially gravitational physics. The relation between general relativity and quantum mechanics is of particular interest. We report the recent result of G. Etesi that large exotic R4's are Ricci-flat and Koehler so that they...
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Dr Alexander Vikmancontributed talk
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Prof. Shinji Mukohyama