7 papers
Cosmic birefringence from a joint analysis of ACT and Planck
Johannes R. Eskilt
Dark matter and dark energy could be ultra-light pseudoscalar fields that couple to electromagnetism through a Chern-Simons term. This would cause a parity-breaking rotation of the…
Cosmic topology. Part IIb. Eigenmodes, correlation matrices, and detectability of non-orientable Euclidean manifolds
Craig J. Copi, Amirhossein Samandar, Glenn D. Starkman +13
If the Universe has non-trivial spatial topology, observables depend on both the parameters of the spatial manifold and the position and orientation of the observer. In infinite Eu…
Cosmic topology. Part IIIb. Eigenmodes and correlation matrices of spin-2 perturbations in orientable Euclidean manifolds
Amirhossein Samandar, Javier Carrón Duque, Craig J. Copi +13
We study the eigenmodes of the spin-2 Laplacian in orientable Euclidean manifolds and their implications for the tensor-induced part of the cosmic microwave background (CMB) temper…
Cosmic topology. Part I. Limits on orientable Euclidean manifolds from circle searches
Pip Petersen, Yashar Akrami, Craig J. Copi +9
The Einstein field equations of general relativity constrain the local curvature at every point in spacetime, but say nothing about the global topology of the Universe. Cosmic micr…
Cosmic topology. Part IIIa. Microwave background parity violation without parity-violating microphysics
Amirhossein Samandar, Javier Carrón Duque, Craig J. Copi +11
The standard cosmological model, which assumes statistical isotropy and parity invariance, predicts the absence of correlations between even-parity and odd-parity observables of th…
Cosmic topology. Part IVa. Classification of manifolds using machine learning: a case study with small toroidal universes
Andrius Tamosiunas, Fernando Cornet-Gomez, Yashar Akrami +16
Non-trivial spatial topology of the Universe may give rise to potentially measurable signatures in the cosmic microwave background. We explore different machine learning approaches…