scholarly journals Propagation of gravitational waves in Chern-Simons axion Einstein gravity

2019 ◽  
Vol 100 (8) ◽  
Author(s):  
Shin’ichi Nojiri ◽  
S. D. Odintsov ◽  
V. K. Oikonomou ◽  
Arkady A. Popov
Keyword(s):  
Gravitational Waves ◽  
Einstein Gravity ◽  
Chern Simons

scholarly journals Resonance instability of primordial gravitational waves during inflation in Chern–Simons gravity

2021 ◽  
Vol 81 (3) ◽  
Author(s):  
Chengjie Fu ◽  
Jing Liu ◽  
Tao Zhu ◽  
Hongwei Yu ◽  
Puxun Wu
Keyword(s):  
Energy Spectrum ◽  
Periodic Function ◽  
Gravitational Waves ◽  
Infrared Region ◽  
Einstein Gravity ◽  
Model Parameters ◽  
Primordial Gravitational Waves ◽  
Chern Simons ◽  
Matter Fields ◽  
Sharp Cutoff

AbstractWe investigate axion inflation where the gravitational Chern–Simons term is coupled to a periodic function of the inflaton. We find that tensor perturbations with different polarizations are amplified in different ways by the Chern–Simons coupling. Depending on the model parameters, the resonance amplification results in a parity-violating peak or a board plateau in the energy spectrum of gravitational waves, and the sharp cutoff in the infrared region constitutes a characteristic distinguishable from stochastic gravitational wave backgrounds produced by matter fields in Einstein gravity.

scholarly journals Chern-Simons gravity dual of BCFT

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Tadashi Takayanagi ◽  
Takahiro Uetoko
Keyword(s):  
Field Theory ◽  
Conformal Field Theory ◽  
Entanglement Entropy ◽  
Einstein Gravity ◽  
Conformal Field ◽  
Holographic Entanglement Entropy ◽  
The World ◽  
Higher Spin ◽  
End Of The World ◽  
Chern Simons

Abstract In this paper we provide a Chern-Simons gravity dual of a two dimensional conformal field theory on a manifold with boundaries, so called boundary conformal field theory (BCFT). We determine the correct boundary action on the end of the world brane in the Chern-Simons gauge theory. This reproduces known results of the AdS/BCFT for the Einstein gravity. We also give a prescription of calculating holographic entanglement entropy by employing Wilson lines which extend from the AdS boundary to the end of the world brane. We also discuss a higher spin extension of our formulation.

scholarly journals Inflationary birefringence and baryogenesis

2016 ◽  
Vol 25 (11) ◽  
pp. 1640013 ◽  
Author(s):  
Stephon Alexander
Keyword(s):  
Gravitational Waves ◽  
Lepton Number ◽  
Gauge Fields ◽  
Lepton Asymmetry ◽  
Complex Phase ◽  
Inflaton Field ◽  
Model Based ◽  
Cross Correlations ◽  
Chern Simons

A decade ago, the first leptogenesis model based on inflation was proposed, where the complex phase of the inflaton field carries lepton number [S. H. S. Alexander, M. E. Peskin and M. M. Sheikh-Jabbari, Phys. Rev. Lett. 96 (2006) 081301, arXiv:hep-th/0403069 ]. If the inflaton field is an axion, it can couple to gravitational waves and gauge fields via Chern–Simons invariants. Due to these couplings, birefringent gravitational and gauge primordial perturbations are created during inflation to generate a lepton asymmetry, establishing a possible connection between nonvanishing TB-parity-violating polarization cross-correlations and leptogenesis. We also discuss the prospect for a subset of these models which can directly source circular (V-mode) polarization in the CMB.

scholarly journals Self-dual Chern-Simons solitons in (2 + 1)-dimensional Einstein gravity

1992 ◽  
Vol 46 (10) ◽  
pp. 4768-4771 ◽  
Author(s):  
D. Cangemi ◽  
Choonkyu Lee
Keyword(s):  
Einstein Gravity ◽  
Chern Simons

The gravitational rainbow beyond Einstein gravity

2019 ◽  
Vol 28 (05) ◽  
pp. 1942003 ◽  
Author(s):  
Claudia de Rham
Keyword(s):  
General Relativity ◽  
Gravitational Waves ◽  
Upper Bound ◽  
Degrees Of Freedom ◽  
Direct Detection ◽  
Einstein Gravity ◽  
Observable Universe ◽  
Basic Properties ◽  
Speed Of Propagation

The recent direct detection of gravitational waves have been successfully used to examine the basic properties of the gravitational degrees of freedom. They set an upper bound on their mass and constrain their speed of propagation with unprecedented accuracy. Within the current realm of observational and theoretical constraints, we explore the possibility for gravity to depart from general relativity (GR) in the infrared and derive the implications on our observable Universe. We also investigate whether these types of models could ever enjoy a standard analytic UV completion.

scholarly journals Averaging over Narain moduli space

2020 ◽  
Vol 2020 (10) ◽  
Author(s):  
Alexander Maloney ◽  
Edward Witten
Keyword(s):  
Einstein Gravity ◽  
Two Dimensions ◽  
Three Dimensions ◽  
One Dimension ◽  
Simons Theory ◽  
Two Dimensional ◽  
Dual Theory ◽  
Recent Developments ◽  
Chern Simons ◽  
Chern Simons Theory

Abstract Recent developments involving JT gravity in two dimensions indicate that under some conditions, a gravitational path integral is dual to an average over an ensemble of boundary theories, rather than to a specific boundary theory. For an example in one dimension more, one would like to compare a random ensemble of two-dimensional CFT’s to Einstein gravity in three dimensions. But this is difficult. For a simpler problem, here we average over Narain’s family of two-dimensional CFT’s obtained by toroidal compactification. These theories are believed to be the most general ones with their central charges and abelian current algebra symmetries, so averaging over them means picking a random CFT with those properties. The average can be computed using the Siegel-Weil formula of number theory and has some properties suggestive of a bulk dual theory that would be an exotic theory of gravity in three dimensions. The bulk dual theory would be more like U(1)2D Chern-Simons theory than like Einstein gravity.

scholarly journals Measuring chiral gravitational waves in Chern-Simons gravity with CMB bispectra

2019 ◽  
Vol 2019 (01) ◽  
pp. 050-050 ◽  
Author(s):  
Nicola Bartolo ◽  
Giorgio Orlando ◽  
Maresuke Shiraishi
Keyword(s):  
Gravitational Waves ◽  
Chern Simons

scholarly journals Gravitational waves propagation in nondynamical Chern–Simons gravity

2017 ◽  
Vol 26 (13) ◽  
pp. 1750148
Author(s):  
A. Martín-Ruiz ◽  
L. F. Urrutia
Keyword(s):  
Surface Layer ◽  
Domain Wall ◽  
Gravitational Waves ◽  
Electromagnetic Waves ◽  
Condensed Matter ◽  
Additional Contribution ◽  
Reflection And Transmission ◽  
First Derivative ◽  
Waves Propagation ◽  
Chern Simons

We investigate the propagation of gravitational waves in linearized Chern–Simons (CS) modified gravity by considering two nondynamical models for the coupling field [Formula: see text]: (i) a domain wall and (ii) a surface layer of [Formula: see text], motivated by their relevance in condensed matter physics. We demonstrate that the metric and its first derivative become discontinuous for a domain wall of [Formula: see text], and we determine the boundary conditions by realizing that the additional contribution to the wave equation corresponds to one of the self-adjoint extensions of the D'Alembert operator. Nevertheless, such discontinuous metric satisfies the area matching conditions introduced by Barrett. On the other hand, the propagation through a surface layer of [Formula: see text] behaves similarly to the propagation of electromagnetic waves in CS extended electrodynamics. In both cases, we calculate the corresponding reflection and transmission amplitudes. As a consequence of the distributional character of the additional terms in the equations that describe wave propagation, the results obtained for the domain wall are not reproduced when the thickness of the surface layer goes to zero, as one could naively expect.

TS-LIKE GRAVITATIONAL WAVES IN 4D EINSTEIN GRAVITY

2010 ◽  
Vol 25 (07) ◽  
pp. 557-566
Author(s):  
YI-HUAN WEI
Keyword(s):  
Gravitational Wave ◽  
Gravitational Waves ◽  
Coordinate Transformation ◽  
Wave Solution ◽  
Einstein Gravity ◽  
Gauge Potential ◽  
Wave Solutions

We propose TS-like class of gravitational wave solutions in 4D Einstein gravity. TS1-like gravitational wave solution is analyzed in detail. On the axis, the gauge potential changes from a finite value to zero at t = τ. The spacetime on the axis approaches the flat one as t → ∞. It is found that by an appropriate parameter substitution and coordinate transformation TS-like gravitational wave solutions in 4D Einstein gravity may be obtained from TS solutions.

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