Circular polarization of gravitational waves from early-Universe helical turbulence

Kahniashvili, Tina; Brandenburg, Axel; Gogoberidze, G.; Mandal, Sayan; Pol, Alberto Roper

doi:10.1103/physrevresearch.3.013193

Cited by 46 publications

(64 citation statements)

References 49 publications

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“…Thus we will neglect the bubble collision contribution which would necessarily require a much stronger transition [81,82,84,157] not feasible in our models featuring polynomial potentials [90]. Further, despite recent progress concerning GWs produced by turbulence [158][159][160] the overall size of this contribution sourced by a phase transition remains uncertain and following [75] we will neglect it. Finally for the range of wall velocities we compute it seems crucial to use updated hybrid calculations of GW generation through sound waves in the plasma [88,91,161,162] predicting a non-trivial dependence of the spectral shape on the wall velocity.…”

Section: Gravitational Wave Signalsmentioning

confidence: 99%

Electroweak bubble wall expansion: gravitational waves and baryogenesis in Standard Model-like thermal plasma

Lewicki

Merchand

Zych

2022

J. High Energ. Phys.

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Computing the properties of the bubble wall of a cosmological first order phase transition at electroweak scale is of paramount importance for the correct prediction of the baryon asymmetry of the universe and the spectrum of gravitational waves. By means of the semiclassical formalism we calculate the velocity and thickness of the wall using as theoretical framework the scalar singlet extension of the SM with a parity symmetry and the SM effective field theory supplemented by a dimension six operator. We use these solutions to carefully predict the baryon asymmetry and the gravitational wave signals. The singlet scenario can easily accommodate the observed asymmetry but these solutions do not lead to observable effects at future gravity wave experiments. In contrast the effective field theory fails at explaining the baryon abundance due to the strict constraints from electric dipole moment experiments, however, the strongest solutions we found fall within the sensitivity of the LISA experiment. We provide a simple analytical approximation for the wall velocity which only requires calculation of the strength and temperature of the transition and works reasonably well in all models tested. We find that generically the weak transitions where the fluid approximation can be used to calculate the wall velocity and verify baryogenesis produce signals too weak to be observed in future gravitational wave experiments. Thus, we infer that GW signals produced by simple SM extensions visible in future experiments are likely to only result from strong transitions described by detonations with highly relativistic wall velocities.

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Section: Gravitational Wave Signalsmentioning

confidence: 99%

Electroweak bubble wall expansion: gravitational waves and baryogenesis in Standard Model-like thermal plasma

Lewicki

Merchand

Zych

2022

J. High Energ. Phys.

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“…Again, these slopes turn to steeper values down to the the diffusive scales. If the driving was continued over a long time interval (long enough for the magnetic field to be processed, i.e., t max ∼ 1) we would recover the Kolmogorov spectrum [65]. The magnetic helicity spectrum around the peak k * is nearly saturated for all values of |σ| considered from 0.3 to 1.…”

Section: Runs With Forced Magnetic Field At the Initial Timementioning

confidence: 86%

“…Added for comparison are the runs in ref. [65] ('forcing (long)'), in which the magnetic field is forced for longer times (t max = 3), and the runs of ref. [81], which contain cases with initial given magnetic field, with forced magnetic field at k * = 60, 600, and 6000, and runs of acoustic turbulence ('acoustic').…”

Section: Observable Gw Energy Density Spectramentioning

confidence: 99%

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Polarization of gravitational waves from helical MHD turbulent sources

Pol,

Mandal,

Brandenburg

et al. 2021

Preprint

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We use direct numerical simulations of decaying primordial hydromagnetic turbulence with helicity to compute the resulting gravitational wave (GW) production and its degree of circular polarization. The turbulence is sourced by magnetic fields that are either initially present or driven by an electromotive force applied for a short duration, given as a fraction of one Hubble time. In both types of simulations, we find a clear dependence of the polarization of the resulting GWs on the fractional helicity of the turbulent source. We find a low frequency tail below the spectral peak shallower than the f 3 scaling expected at super-horizon scales, in agreement with similar recent numerical simulations. This type of spectrum facilitates its observational detection with the planned Laser Interferometer Space Antenna (LISA). We show that driven magnetic fields produce GWs more efficiently than magnetic fields that are initially present, leading to larger spectral amplitudes, and to modifications of the spectral shape. In particular, we observe a sharp drop of GW energy above the spectral peak that is in agreement with the previously obtained results. The helicity does not have a huge impact on the maximum spectral amplitude in any of the two types of turbulence considered. However, the GW spectrum at wave numbers away from the peak becomes smaller for larger values of the magnetic fractional helicity. Such variations of the spectrum are most noticeable when magnetic fields are driven. The degree of circular polarization approaches zero at frequencies below the peak, and reaches its maximum at the peak. At higher frequencies, it stays finite if the magnetic field is initially present, and it approaches zero if it is driven. We predict that the spectral peak of the GW signal can be

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“…The next item would be, if gravitons are commensurate as to DE, in line with our ideas different from [33] would be to investigate the signal from gravitons can be measured appropriately. That would entail doing analysis consistent with [34] as to the quadrupole analysis of GW strength, from perhaps millions of breaking up Black holes as well as the ideas of [35] among other things, for confirmation of optimal techniques.…”

Section: Future Project To Develop Making De Equivalent To a Sea Of Initial Gravitons Via Break Up Of Initial Plank Mass To Slightly Largmentioning

confidence: 99%

Using Kiefer Density Matrix for Time Flow Analysis and How This Links to a Proof of Production of Planck Mass BHs during Inflation and Their Resulting Breakup, Leading to a DE Candidate

Beckwith¹

2021

JHEPGC

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We are using the book "Towards Quantum Gravity" with an article by Claus Kiefer as to a quantum gravity interpretation of the density matrix in the early universe. The density matrix we are using is a one loop approximation, with inflaton value and potential terms, like V (phi) using the Padmanabhan values one can expect if the scale factor is a ~a (Initial) times t ^ gamma. In doing so, we identify two time steps and presume a very small initial time step candidates initial time values which are from a polynomial for time values. A gravity wave analysis concludes our article with inflaton decay, which is finally linked to BHs. And then finally we show using work done by Hawking, et al. how this may give us Planck Sized Black Holes, in the onset of

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Circular polarization of gravitational waves from early-Universe helical turbulence

Cited by 46 publications

References 49 publications

Electroweak bubble wall expansion: gravitational waves and baryogenesis in Standard Model-like thermal plasma

Electroweak bubble wall expansion: gravitational waves and baryogenesis in Standard Model-like thermal plasma

Polarization of gravitational waves from helical MHD turbulent sources

Using Kiefer Density Matrix for Time Flow Analysis and How This Links to a Proof of Production of Planck Mass BHs during Inflation and Their Resulting Breakup, Leading to a DE Candidate

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