Reconstructing cosmic polarization rotation with ResUNet-CMB

Guzman, Eric; Meyers, Joel

doi:10.1088/1475-7516/2022/01/030

Cited by 11 publications

(7 citation statements)

References 111 publications

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“…In future work we plan to apply the modified P ix2P ixHD model to other reconstruction tasks where the small scale structures are missing (e.g., patchy reionization [19] and CMB polarization rotation [30]). Further we plan to include galactic and extra-galactic foreground effects in the input polarization maps, and learn to recover the CMB signal as well as the lensing signal simultaneously.…”

Section: Discussionmentioning

confidence: 99%

High-Resolution CMB Lensing Reconstruction with Deep Learning

Li¹,

Onur²,

Dodelson³

et al. 2022

Preprint

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Next-generation cosmic microwave background (CMB) surveys are expected to provide valuable information about the primordial universe by creating maps of the mass along the line of sight. Traditional tools for creating these lensing convergence maps include the quadratic estimator and the maximum likelihood based iterative estimator. Here, we apply a generative adversarial network (GAN) to reconstruct the lensing convergence field. We compare our results with a previous deep learning approach -Residual-UNet -and discuss the pros and cons of each. In the process, we use training sets generated by a variety of power spectra, rather than the one used in testing the methods.

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Section: Discussionmentioning

confidence: 99%

High-Resolution CMB Lensing Reconstruction with Deep Learning

Li¹,

Onur²,

Dodelson³

et al. 2022

Preprint

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“…Moreover, linear stringy features imply phase correlations between Fourier modes of the rotation field, the confirmation of which will provide decisive evidence for topological defects as the origin of the ALP field. Extracting this information calls for further development of non-Gaussian statistical tests for polarization rotations in the CMB, or the employment of neural-network-based reconstruction techniques [46].…”

Section: Discussionmentioning

confidence: 99%

Probing cosmic strings by reconstructing polarization rotation of the cosmic microwave background

Yin,

Dai,

Ferraro

2021

Preprint

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Cosmic birefringence-the rotation of the polarization of the cosmic microwave background (CMB) photons as they travel to the Earth-is a smoking gun for axion-like particles (ALPs) that interact with the photon. It has recently been suggested that topological defects in the ALP field called cosmic strings can cause polarization rotation in quantized amounts that are proportional to the electromagnetic chiral anomaly coefficient A, which holds direct information about physics at very high energies. In this work, we study the detectability of a random network of cosmic strings through estimating rotation using quadratic estimators (QEs). We show that the QE derived from the maximum likelihood estimator is equivalent to the recently proposed global-minimum-variance QE; the classic Hu-Okamoto QE equals the global-minimum-variance QE under special conditions, but is otherwise still nearly globally optimal. We calculate the sensitivity of QEs to cosmic birefringence from string networks, for the Planck satellite mission, as well as for third-and fourth-generation ground-based CMB experiments. Using published binned rotation power spectrum derived from the Planck 2015 polarization data, we obtain a constraint A 2 ξ 0 < 0.93 at the 95% confidence level, where ξ 0 is the total length of strings in units of the Hubble scale per Hubble volume, for a phenomenological but reasonable string network model describing a continuous distribution of string sizes. Looking forward, experiments such as the Simons Observatory and CMB-S4 will either discover or falsify the existence of an ALP string network for the theoretically plausible parameter space A 2 ξ 0 0.01.

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“…Just as is the case for lensing reconstruction, reducing the lensing-induced power, especially on small scales and in B-mode polarization, will reduce the variance of these estimators; see refs. [96,97] for a quantitative discussion of the benefits of delensing for patchy reionization and cosmic polarization rotation. Delensing also helps to mitigate biases that arise in reconstructing fields whose effects on the CMB are not orthogonal to lensing, though some form of bias-hardening is still required to eliminate the bias due to residual lensing [98].…”

Section: Reconstruction Of Other Fieldsmentioning

confidence: 99%

The benefits of CMB delensing

Hotinli

Meyers

Trendafilova

et al. 2022

J. Cosmol. Astropart. Phys.

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The effects of gravitational lensing of the cosmic microwave background (CMB) have been measured at high significance with existing data and will be measured even more precisely in future surveys. Reversing the effects of lensing on the observed CMB temperature and polarization maps provides a variety of benefits. Delensed CMB spectra have sharper acoustic peaks and more prominent damping tails, allowing for improved inferences of cosmological parameters that impact those features. Delensing reduces B-mode power, aiding the search for primordial gravitational waves and allowing for lower variance reconstruction of lensing and other sources of secondary CMB anisotropies. Lensing-induced power spectrum covariances are reduced by delensing, simplifying analyses and improving constraints on primordial non-Gaussianities. Biases that result from incorrectly modeling nonlinear and baryonic feedback effects on the lensing power spectrum are mitigated by delensing. All of these benefits are possible without any changes to experimental or survey design. We develop a self-consistent, iterative, all-orders treatment of CMB delensing on the curved sky and demonstrate the impact that delensing will have with future surveys.

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Reconstructing cosmic polarization rotation with ResUNet-CMB

Cited by 11 publications

References 111 publications

High-Resolution CMB Lensing Reconstruction with Deep Learning

High-Resolution CMB Lensing Reconstruction with Deep Learning

Probing cosmic strings by reconstructing polarization rotation of the cosmic microwave background

The benefits of CMB delensing

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