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We present a new approach to early universe cosmology. Inflation is replaced by a phase transition in which both matter and geometry are created simultaneously. We calculate the spectrum of metric perturbations and show that it is flat. We…

General Relativity and Quantum Cosmology · Physics 2008-05-28 Olaf Dreyer

Hydrogen recombination is one of the most important atomic processes in many astrophysical objects such as Type II supernova (SN~II) atmospheres, the high redshift universe during the cosmological recombination era, and H II regions in the…

Solar and Stellar Astrophysics · Physics 2015-05-18 Soma De , E. Baron , Peter H. Hauschildt

Photons excited into ground state modes at finite temperature display partitioning among photon phases, lifetimes and distances travelled since creation. These distributions set the distance from an interface a created photon has some…

Optics · Physics 2022-04-28 Geoff B Smith , Angus R Gentle , Matthew D Arnold

Advancing temporal resolution in computation, signal modulation, and measurement is crucial for pushing the frontiers of modern science and technology. Optical resonators have recently demonstrated computational operations at frequencies…

Optics · Physics 2025-10-31 Asaf Farhi

The electromagnetically induced transparency (EIT) phenomenon in earlier universe is considered. We evaluated the elementary processes of the single scattering of photon on the hydrogen atom with the purpose of their use in the tasks of the…

Atomic Physics · Physics 2022-02-10 D. Solovyev , V. K. Dubrovich

The recombination history of the Universe depends exponentially on the temperature, T_0, of the cosmic microwave background. Therefore tiny changes of T_0 are expected to lead to significant changes in the free electron fraction. Here we…

Astrophysics · Physics 2009-11-13 J. Chluba , R. A. Sunyaev

Dark sectors consisting of atomic constituents (electrons, protons, and photons) offer a well-motivated extension to the Standard Model while providing multiple avenues for phenomenological study. In this work, we explore the impact of…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-17 Duncan K. Adams , Jared Barron , Bryce Cyr , Xiuyuan Zhang

Cold dark matter (DM) scenario may be cured of several problems by involving self-interaction of dark matter. Viability of the models of long-range interacting DM crucially depends on the effectiveness of recombination of the DM particles,…

Cosmology and Nongalactic Astrophysics · Physics 2016-09-06 K. M. Belotsky , E. A. Esipova , A. A. Kirillov

We calculate the He I case B recombination cascade spectrum using improved radiative and collisional data. We present new emissivities over a range of electron temperatures and densities. The differences between our results and the current…

Astrophysics · Physics 2009-11-10 R. L. Porter , R. P. Bauman , G. J. Ferland , K. B. MacAdam

In this paper we compute the emission coming from the direct recombination of free electrons to a given shell (n>=2) during the epoch of cosmological hydrogen recombination. This contribution leads to a total of one photon per recombined…

Astrophysics · Physics 2009-11-11 J. Chluba , R. A. Sunyaev

The primordial power spectrum describes the initial perturbations that seeded the large-scale structure we observe today. It provides an indirect probe of inflation or other structure-formation mechanisms. In this letter, we recover the…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-05 F. Lanusse , P. Paykari , J. -L. Starck , F. Sureau , J. Bobin , A. Rassat

The primordial power spectrum is an indirect probe of inflation or other structure-formation mechanisms. We introduce a new method, named \textbf{PRISM}, to estimate this spectrum from the empirical cosmic microwave background (CMB) power…

Cosmology and Nongalactic Astrophysics · Physics 2014-07-01 P. Paykari , F. Lanusse , J. -L. Starck , F. Sureau , J. Bobin

Spectral distortion anisotropies of the cosmic microwave background (CMB) provide a new probe of the early Universe that can be accessed using traditional CMB imaging techniques. It is possible to compute the creation and evolution of…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-17 Jens Chluba , Sara Evangelista , Tom Daman , Geoff Vasil

Various interference effects are known to exist in the process of high harmonic generation (HHG) both at the single atom and macroscopic levels. In particular, the quantum path difference between the long and short trajectories of electron…

The primordial matter power spectrum quantifies fluctuations in the distribution of dark matter immediately following inflation. Over cosmic time, over-dense regions of the primordial density field grow and collapse into dark matter halos,…

Cosmology and Nongalactic Astrophysics · Physics 2022-03-30 Daniel Gilman , Andrew Benson , Jo Bovy , Simon Birrer , Tommaso Treu , Anna Nierenberg

The primordial power spectrum describes the initial perturbations in the Universe which eventually grew into the large-scale structure we observe today, and thereby provides an indirect probe of inflation or other structure-formation…

Cosmology and Nongalactic Astrophysics · Physics 2011-02-11 Paniez Paykari , Andrew H. Jaffe

Accurate computations of spectral distortions of the cosmic microwave background (CMB) are required for constraining energy release scenarios at redshifts $z\gtrsim 10^3$. The existing literature focuses on distortions that are small…

Cosmology and Nongalactic Astrophysics · Physics 2022-08-17 Sandeep Kumar Acharya , Jens Chluba

Here we report new ${\it ab initio}$ calculations of the effective recombination coefficients for the \ion{N}{ii} recombination spectrum. We have taken into account the density dependence of the coefficients arising from the relative…

Solar and Stellar Astrophysics · Physics 2015-05-27 X. Fang , P. J. Storey , X. -W. Liu

Reconstructing the shape of the primordial power spectrum in a model independent way from cosmological data is a useful consistency check on what is usually assumed regarding early universe physics. It is also our primary window to unknown…

Astrophysics · Physics 2008-11-26 Pia Mukherjee , Yun Wang

We review the distortions of spectra of relic neutrinos due to the interactions with electrons, positrons, and neutrinos in the early universe. We solve integro-differential kinetic equations for the neutrino density matrix, including…

High Energy Physics - Phenomenology · Physics 2022-12-05 Kensuke Akita , Masahide Yamaguchi