NEB-20

Session

Keynote

Sep 11, 2023, 3:00 PM

97. Spin and integrability in the relativistic two-body problem

Vojtěch Witzany

9/11/23, 3:00 PM

As the reach and sensitivity of gravitational-wave detectors continues to grow, so do the requirements on our understanding of the evolution of compact binaries. When the components of the binary spin at general inclinations, there is, in principle, a sufficient number of degrees of freedom to break integrability of the evolution. However, layer after layer various integrable structures appear...

63. Non-Noetherian conformal scalar fields

Mokhtar Hassaine

9/13/23, 12:00 PM

Recently, an extension of the standard four-dimensional scalar conformal action, yielding a secondorder field equation that remains conformally invariant, was proposed. In spite of this, the corresponding action is not invariant under conformal transformations and this motivates us to define the notion of non-Noetherian conformal scalar field. In this article, we go further by determining the...

64. Searches for low-frequency gravitational waves with pulsar timing arrays

John Antoniadis

9/13/23, 12:30 PM

I will describe recent developments related to the search for low-frequency gravitational waves with pulsar timing arrays

65. Hidden symmetries from distortions of the conformal structure

Nikolaos Dimakis (Center for Theoretical Physics, College of Physical Science and Technology, Sichuan University, China)

9/13/23, 3:00 PM

In this work we explore the motion of massive particles in curved backgrounds. We demonstrate how new symmetries emerge by distorting the conformal vectors of the spacetime metric and how they lead to additional conserved quantities. Beside (pseudo-)Riemannian geometry, we also apply this scheme to certain Finslerian extensions. Finally, we explain how the emergence of these symmetries is...

83. Rotating black holes embedded in a cosmological background for scalar-tensor theories

Eugeny Babichev

9/14/23, 12:00 PM

I will present solutions of DHOST theories describing a rotating black hole embedded in an expanding universe. The solution is constructed by conformal transformation of a stealth Kerr(-de Sitter) black hole. The conformal factor depends explicitly on the scalar field - but not on its derivative - and defines the new theory. The scalar field of the stealth Kerr(-de Sitter) solution depends on...

84. Renormalized Volume/Area from Conformal Gravity

Rodrigo Olea

9/14/23, 12:30 PM

Within a holographic framework, we explore the physical consequences of embedding Einstein gravity with negative cosmological constant in Conformal Gravity in four dimensions. In the bulk, the procedure is equivalent to Holographic Renormalization, as the Einstein-AdS action appears augmented by the correct boundary counterterms. In codimension-2, 4D Conformal Gravity induces a 2D conformal...

85. Automorphisms in Bianchi (-like) geometries

Theodosios Christodoulakis (National and Kapodistrian University of Athens)

9/14/23, 3:00 PM

The relevant time-depended automorphisms are used to reduce the form of
the line-element. There are, thus revealed, enough first integrals of motion
which enable the presentation of the entire solution space for the 5-dim
Kasner (4 A_1) and/or Type V (A^{1,1}_{4,5}) models.