Detecting rotation from lensing in the CMB

Article Article scientifique Article Detecting rotation from lensing in the CMB eng 2025-07-23 2025-07-01 author Carron Julien 0000-0002-5751-1392 935832 Département de physique théorique (FITEO) author Di Dio Enea 0000-0002-5803-1382 732200 author Durrer Ruth 0000-0001-9833-2086 106998 Département de physique théorique (FITEO) 069 10.1088/1475-7516/2025/07/069 1475-7516 https://iopscience.iop.org/article/10.1088/1475-7516/2025/07/069 An excellent estimate of the lensing signal is expected from the availability of deep and high-resolution polarization data in the near future. This is most important to allow for efficient delensing, needed to detect the primordial B-mode power and with it the famous tensor-to-scalar ratio. Here we discuss in a joint manner estimators of the rotation of polarization, of the second order lensing field rotation, and standard gradient lensing reconstruction. All are most efficient when able to probe the <i>EB</i> power created locally, have comparable reconstruction noise in this regime, and can benefit substantially from delensing. We discuss several ongoing and planned CMB experiments. We determine their noise for lensing field rotation and polarization rotation and discuss their prospects for measuring these effects. There is an on-going controversy on whether the lensing field rotation also rotates the polarization — if so this will be observed at high significance soon with already on going observations of the South Pole Telescope, SPT-3G, in cross-correlation with tracers of large scale structure, as we show in this paper. Dewey 500.2 37 Département de physique théorique 133 false Journal of cosmology and astroparticle physics 2025 07 15e6c88a-2343-4e4c-a789-972f2f46d354 Article (Published version) Public Carron_2025_J._Cosmol._Astropart._P.pdf 1516486 application/pdf CC BY-4.0 fb3183cb0a3bb843ce6abad265eca47abcd5a1f9d7ee4c53894af3fa6131199c openAccess Faculté des sciences / Section de physique / Département de physique théorique

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Detecting rotation from lensing in the CMB	Journal of cosmology and astroparticle physics			2025	15	1,395

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Carron, Julien