Effects of gravitational Chern-Simons during Axion-SU(2) inflation

Mirzagholi, Leila; Komatsu, Eiichiro; Lozanov, Kaloian D.; Watanabe, Yuki

doi:10.1088/1475-7516/2020/06/024

Cited by 29 publications

(18 citation statements)

References 64 publications

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“…The action may contain the so-called 'gravitational Chern-Simons (GCS) term', χR R255 , which also induces parityviolating correlations in the CMB data 27,256,257 . When considered simultaneously with I CS , the impact of GCS is minor 258 , justifying our ignoring this term in this section.…”

Section: Non-abelian Gauge Fieldmentioning

confidence: 99%

New physics from the polarised light of the cosmic microwave background

Komatsu

2022

Preprint

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Cosmology requires new physics beyond the Standard Model of elementary particles and fields. What is the fundamental physics behind dark matter and dark energy? What generated the initial fluctuations in the early Universe? Polarised light of the cosmic microwave background (CMB) may hold the key to answers. In this article, we discuss two new developments in this research area. First, if the physics behind dark matter and dark energy violates parity symmetry, their coupling to photons rotates the plane of linear polarisation as the CMB photons travel more than 13 billion years. This effect is known as 'cosmic birefringence': space filled with dark matter and dark energy behaves as if it were a birefringent material, like a crystal. A tantalising hint for such a signal has been found with the statistical significance of 3σ . Next, the period of accelerated expansion in the very early Universe, called 'cosmic inflation', produced a stochastic background of primordial gravitational waves (GW). What generated GW? The leading idea is vacuum fluctuations in spacetime, but matter fields could also produce a significant amplitude of primordial GW. Finding its origin using CMB polarisation opens a new window into the physics behind inflation. These new scientific targets may influence how data from future CMB experiments are collected, calibrated, and analysed.

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Section: Non-abelian Gauge Fieldmentioning

confidence: 99%

New physics from the polarised light of the cosmic microwave background

Komatsu

2022

Preprint

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“…with g being the gauge field self-coupling constant, and F aµν is its dual. We ignore the effect of the gravitational Chern-Simons term R R because its effect on the SGWB is sub-dominant compared to the F F term [72].…”

Section: Spectator Axion-su(2) Modelmentioning

confidence: 99%

Measuring the spectrum of primordial gravitational waves with CMB, PTA and Laser Interferometers

Campeti,

Komatsu,

Poletti

et al. 2020

Preprint

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We investigate the possibility of measuring the primordial gravitational wave (GW) signal across 23 decades in frequencies, using the cosmic microwave background (CMB), pulsar timing arrays (PTA), and direct detection with laser and atomic interferometers. For the CMB and PTA experiments we consider the LiteBIRD mission and the Square Kilometer Array (SKA), respectively. For the interferometers we consider space mission proposals including the Laser Interferometer Space Antenna (LISA), the Big Bang Observer (BBO), the Deci-hertz Interferometer Gravitational wave Observatory (DECIGO), the µAres experiment, the Decihertz Observatory (DO), and the Atomic Experiment for Dark Matter and Gravity Exploration in Space (AEDGE), as well as the ground-based Einstein Telescope (ET) and Cosmic Explorer (CE) proposals. We implement the mathematics needed to compute sensitivities for both CMB and interferometers, and derive the response functions for the latter from the first principles. We also evaluate the effect of the astrophysical foreground contamination in each experiment. We present binned sensitivity curves and error bars on the energy density parameter, Ω GW h 2 , as a function of frequency for two representative classes of models for the stochastic background of primordial GW: the quantum vacuum fluctuation in the metric from single-field slow-roll inflation, and the source-induced tensor perturbation from the spectator axion-SU(2) inflation models. We find excellent prospects for joint measurements of the GW spectrum by CMB and space-borne direct detection mission proposals.

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“…In fact, the current constraints allow for variety of non-conventional models, such as models with non-attractor phases [6][7][8][9][10][11], multi-field models (see e.g. the reviews [12,13]), models with extra (spinning) fields [14,15] and extra gauge fields [16][17][18][19][20][21], models with non-Bunch Davies initial states [22][23][24], and alternate symmetry breaking patterns [25][26][27][28][29][30][31][32][33][34][35][36][37]. Some of these alternative descriptions of the inflationary epoch lead to non-negligible primordial bispectra peaking in the so-called squeezed limit, i.e.…”

Section: Introductionmentioning

confidence: 99%

Primordial tensor bispectra in $μ$-CMB cross-correlations

Orlando,

Meerburg,

Patil

2021

Preprint

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Cross-correlations between Cosmic Microwave Background (CMB) temperature and polarization anisotropies and µ-spectral distortions have been considered to measure (squeezed) primordial scalar bispectra in a range of scales inaccessible to primary CMB bispectra. In this work we address whether it is possible to constrain tensor non-Gaussianities with these cross-correlations. We find that only primordial tensor bispectra with anisotropies leave distinct signatures, while isotropic tensor bispectra leave either vanishing or highly suppressed signatures. We discuss how the kind of anisotropies and the parity state in primordial bispectra determine the non-zero cross-correlations. By employing the so-called BipoSH formalism to capture the observational effects of these anisotropies, we make Fisher-forecasts to assess the detection prospects from µT , µE and µB cross-correlations. Observing anisotropies in squeezed γγγ and γγζ bispectra is going to be challenging as the imprint of tensor perturbations on µ-distortions is subdominant to scalar perturbations, therefore requiring a large, independent amplification of the effect of tensor perturbations in the µ-epoch. In absence of such a mechanism, anisotropies in squeezed ζζγ bispectrum are the most relevant sources of µT , µE and µB cross-correlations. In particular, we point out that in models where anisotropies in ζζζ leave potentially observable signatures in µT and µE, the detection prospects of anisotropies in ζζγ from µB are enhanced.

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Effects of gravitational Chern-Simons during Axion-SU(2) inflation

Cited by 29 publications

References 64 publications

New physics from the polarised light of the cosmic microwave background

New physics from the polarised light of the cosmic microwave background

Measuring the spectrum of primordial gravitational waves with CMB, PTA and Laser Interferometers

Primordial tensor bispectra in $μ$-CMB cross-correlations

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