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Observations of the Cosmic Microwave Background (CMB) have cemented the notion that the large-scale Universe is both statistically homogeneous and isotropic. But is it invariant also under reflections? To probe this we require…

Cosmology and Nongalactic Astrophysics · Physics 2023-09-25 Oliver H. E. Philcox

The linear polarization of the Cosmic Microwave Background (CMB) is highly sensitive to parity-violating physics at the surface of last scattering, which might cause mixing of E and B modes, an effect known as {\it cosmic birefringence}.…

Cosmology and Nongalactic Astrophysics · Physics 2023-11-30 Nils A. Nilsson , Christophe Le Poncin-Lafitte

The conventional $\Lambda$CDM cosmological model supplemented by the inflation concept describes the Universe very well. However, there are still a few concerns: new Planck data impose constraints on the shape of the inflaton potential,…

Cosmology and Nongalactic Astrophysics · Physics 2015-11-03 Branislav Vlahovic , Maxim Eingorn , Cosmin Ilie

In the context of inflationary scenarios, the observed large angle anisotropy of the Cosmic Microwave Background (CMB) temperature is believed to probe the primordial metric perturbations from inflation. Although the perturbations from…

Astrophysics · Physics 2019-08-17 Somnath Bharadwaj , Dipak Munshi , Tarun Souradeep

We consider the hypothesis that nonlocal, omnidirectional, causally-coherent quantum entanglement of inflationary horizons may account for some well-known measured anomalies of Cosmic Microwave Background (CMB) anisotropy on large angular…

General Relativity and Quantum Cosmology · Physics 2022-02-16 Craig Hogan , Stephan S. Meyer

The Cosmological Principle assumes a statistically isotropic Universe, but the Cosmic Microwave Background (CMB) exhibits some anomalous statistical features, such as the hemispherical power asymmetry, that challenge this core assumption.…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-25 Javier Carrón Duque , Mikel Martin Barandiaran , Joseba Martínez-Arrizabalaga

The Cosmic Microwave Background (CMB) provides a precious window on fundamental physics at very high energy scales, possibly including quantum gravity, GUTs and supersymmetry. The CMB has already enabled defect-based rivals to inflation to…

Astrophysics · Physics 2009-09-11 John Ellis

Recently, the cross-correlation between $E$- and $B$-mode polarization of the cosmic microwave background (CMB), which is well explained by cosmic birefringence with rotation angle $\beta\approx 0.3$ deg, has been found in CMB polarization…

Cosmology and Nongalactic Astrophysics · Physics 2022-12-07 Tomohiro Fujita , Yuto Minami , Maresuke Shiraishi , Shuichiro Yokoyama

We propose an evolutional scenario of the universe which starts from quantum states with conformal invariance, passing through the inflationary era, and then makes transition to the conventional Einstein space-time. The space-time dynamics…

Astrophysics · Physics 2008-11-26 Ken-ji Hamada , Shinichi Horata , Tetsuyuki Yukawa

Inflationary cosmology has proved to be the most successful at predicting the properties of the anisotropies observed in the cosmic microwave background (CMB). In this essay we show that quantum field renormalization significantly…

General Relativity and Quantum Cosmology · Physics 2014-11-20 Ivan Agullo , Jose Navarro-Salas , Gonzalo J. Olmo , Leonard Parker

The hypothesis of the self-induced collapse of the inflaton wave function was proposed as responsible for the emergence of inhomogeneity and anisotropy at all scales. This proposal was studied within an almost de Sitter space-time…

Cosmology and Nongalactic Astrophysics · Physics 2016-12-28 Micol Benetti , Susana J. Landau , Jailson S. Alcaniz

Measurements of CMB temperature fluctuations by the Wilkinson Microwave Anisotropy Probe (WMAP) indicate that the fluctuation amplitude in one half of the sky differs from the amplitude in the other half. We show that such an asymmetry…

Astrophysics · Physics 2008-12-30 Adrienne L. Erickcek , Marc Kamionkowski , Sean M. Carroll

There have been vigorous research attempts to test various modified gravity theories by usingphysics of the cosmic microwave background (CMB). Meanwhile, symmetry breaking such as Higgsmechanism is one of the most important phenomena in…

General Relativity and Quantum Cosmology · Physics 2020-07-01 Jiwon Park , Tae Hoon Lee

We investigate whether non-adiabatic perturbations from inflation could produce an asymmetric distribution of temperature anisotropies on large angular scales in the cosmic microwave background (CMB). We use a generalised non-linear $\delta…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-23 Hooshyar Assadullahi , Hassan Firouzjahi , Mohammad Hossein Namjoo , David Wands

In the standard inflationary paradigm the inhomogeneities observed in the CMB arise from quantum fluctuations of an initially homogeneous and isotropic vacuum state. This picture suffers from two well-known weaknesses. First, it assumes…

General Relativity and Quantum Cosmology · Physics 2026-01-21 Gabriel R. Bengochea , Gabriel Leon , Alejandro Perez

We discuss the polarization signature of primordial gravitational waves imprinted in cosmic microwave background (CMB) anisotropies. The high-energy physics motivated by superstring theory or M-theory generically yield parity violating…

Astrophysics · Physics 2009-06-23 Shun Saito , Kiyotomo Ichiki , Atsushi Taruya

The problem of formulating a fully consistent quantum gravity theory (QGT) has not yet been solved. Even before we are able to work out the details of a complete theory, however, we do know some important qualitative features to be expected…

Astrophysics · Physics 2007-05-23 Rosanne Di Stefano , L. H. Ford , Hongwei Yu , D. J. Fixsen

Fluctuations in the intensity and polarization of the cosmic microwave background (CMB) and the large-scale distribution of matter in the universe each contain clues about the nature of the earliest moments of time. The next generation of…

Anomalies in the cosmic microwave background (CMB) refer to features that have been observed, mostly at large angular scales, and which show some tension with the statistical predictions of the standard $\Lambda$CDM model. In this work, we…

General Relativity and Quantum Cosmology · Physics 2021-05-28 Ivan Agullo , Dimitrios Kranas , V. Sreenath

Although cosmological observations suggest that the fluctuations of seed fields are almost Gaussian, the possibility of a small deviation of their fields from Gaussianity is widely discussed. Theoretically, there exist numerous inflationary…

Cosmology and Nongalactic Astrophysics · Physics 2022-09-21 Maresuke Shiraishi