Livine, Etera

In the context of quantum gravity, we clarify entanglement calculations on spin networks: we distinguish the gauge-invariant entanglement between intertwiners located at the nodes and the entanglement between spin states located on the network’s links. We compute explicitly these two notions of entanglement between neighboring nodes and show that t...

Bautista, Teresa Benevides, André Dabholkar, Atish

Virtual massless particles in quantum loops lead to nonlocal effects which can have interesting consequences, for example, for primordial magnetogenesis in cosmology or for computing finite N corrections in holography. We describe how the quantum effective actions summarizing these effects can be computed efficiently for Weyl-flat metrics by integr...

Sahlén, Martin Silk, Joseph

Combining galaxy cluster and void abundances is a novel, powerful way to constrain deviations from general relativity and the ΛCDM model. For a flat wCDM model with growth of large-scale structure parametrized by the redshift-dependent growth index γ(z)=γ0+γ1z/(1+z) of linear matter perturbations, combining void and cluster abundances in future sur...

Durakovic, Amel Hunt, Paul Mukherjee, Suvodip Sarkar, Subir Souradeep, Tarun

We consider the possibility that the primordial curvature perturbation is direction-dependent. To first order this is parameterised by a quadrupolar modulation of the power spectrum and results in statistical anisotropy of the CMB, which can be quantified using `bipolar spherical harmonics'. We compute these for the Planck DR2-2015 SMICA map and es...

Adamek, Julian

In order to keep pace with the increasing data quality of astronomical surveys the observed source redshift has to be modeled beyond the well-known Doppler contribution. In this article I want to examine the gauge issue that is often glossed over when one assigns a perturbed redshift to simulated data generated with a Newtonian N-body code. A caref...

Ben Geloun, Joseph Koslowski, Tim Oriti, Daniele Pereira, Antonio

In this paper we consider the complete momentum-independent quartic order truncation for the effective average action of a real Abelian rank 3 tensorial group field theory. This complete truncation includes non-melonic as well as double-trace interactions. In the usual functional renormalization group perspective, the inclusion of more operators th...

Alsaleh, Salwa Alasfar, Lina Faizal, Mir Ali, Ahmed

In this paper, we analyze the classical geometric flow as a dynamical system. We obtain an action for this system, such that its equation of motion is the Raychaudhuri equation. This action will be used to quantize this system. As the Raychaudhuri equation is the basis for deriving the singularity theorems, we will be able to understand the effects...

Fujita, Tomohiro Namba, Ryo Tada, Yuichiro

We show that a detectable tensor-to-scalar ratio (r≥10−3) on the CMB scale can be generated even during extremely low energy inflation which saturates the BBN bound ρinf≈(30MeV)4 . The source of the gravitational waves is not quantum fluctuations of graviton but those of SU(2) gauge fields, energetically supported by coupled axion fields. The curva...

Zhang, P.M. Duval, C. Gibbons, G.W. Horvathy, P.A.

Circularly polarized gravitational sandwich waves exhibit, as do their linearly polarized counterparts, the Velocity Memory Effect: freely falling test particles in the flat after-zone fly apart along straight lines with constant velocity. In the inside zone their trajectories combine oscillatory and rotational motions in a complicated way. For cir...

Sahlén, Martin Silk, Joseph

Combining galaxy cluster and void abundances is a novel, powerful way to constrain deviations from general relativity and the ΛCDM model. For a flat wCDM model with growth of large-scale structure parametrized by the redshift-dependent growth index γ(z)=γ0+γ1z/(1+z) of linear matter perturbations, combining void and cluster abundances in future sur...