Ghosh, Shamik Liu, Yang Zhang, Le Li, Siyu Zhang, Junzhou Wang, Jiaxin Chen, Jiming Delabrouille, Jacques Dou, Jiazheng Remazeilles, Mathieu
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AliCPT is the first Chinese cosmic microwave background (CMB) experiment which will make the most precise measurements of the CMB polarization in the northern hemisphere. The key science goal for AliCPT is the detection of primordial gravitational waves (PGWs). It is well known that an epoch of cosmic inflation, in the very early universe, can prod...

Fumagalli, Jacopo Palma, Gonzalo A. Renaux-Petel, Sébastien Sypsas, Spyros Witkowski, Lukas T. Zenteno, Cristobal

We show that a scalar excited state with large occupation numbers during inflation leads to an enhancement of tensor modes and a characteristic pattern of order-one oscillations in the associated stochastic gravitational wave background (SGWB) sourced during inflation. An effective excited state, i.e. a departure from the Bunch-Davies vacuum, can e...

Achúcarro, Ana Biagetti, Matteo Braglia, Matteo Cabass, Giovanni Castorina, Emanuele Caldwell, Robert Chen, Xingang Coulton, William Flauger, Raphael Fumagalli, Jacopo
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Cosmic inflation provides a window to the highest energy densities accessible in nature, far beyond those achievable in any realistic terrestrial experiment. Theoretical insights into the inflationary era and its observational probes may therefore shed unique light on the physical laws underlying our universe. This white paper describes our current...

Ade, P.A.R. Ahmed, Z. Amiri, M. Barkats, D. Thakur, R. Basu Beck, D. Bischoff, C. Bock, J.J. Boenish, H. Bullock, E.
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For the past decade, the BICEP/Keck collaboration has been operating a series of telescopes at the Amundsen-Scott South Pole Station measuring degree-scale $B$-mode polarization imprinted in the Cosmic Microwave Background (CMB) by primordial gravitational waves (PGWs). These telescopes are compact refracting polarimeters mapping about 2% of the sk...

Fumagalli, Jacopo Pieroni, Mauro Renaux-Petel, Sébastien Witkowski, Lukas T.

Oscillations in the frequency profile of the stochastic gravitational wave background are a characteristic prediction of small-scale features during inflation. In this paper we present a first investigation of the detection prospects of such oscillations with the upcoming space-based gravitational wave observatory LISA. As a proof of principle, we ...

Schander, S. Thiemann, T.

This is the final paper in a series of four in which we incorporate backreaction among the homogeneous and between the homogeneous and inhomogeneous degrees of freedom in quantum cosmological perturbation theory using space adiabatic methods. Here, we consider the gauge-invariant scalar (Mukhanov-Sasaki) and tensor (primordial gravitational wave) p...

Arani, F. Shojaei Harouni, M. Bagheri Lamine, B. Blanchard, A.

We establish a new formalism to describe the interaction of an optical system with a background of gravitational waves based on optical medium analogy. Besides reproducing the basic formula for the response of a LISA-type interferometer in terms of the phase shift of light, other classical observables of the electromagnetic field such as light-bend...

Collaboration, BICEP/Keck Ade, P. A. R. Ahmed, Z. Amiri, M. Barkats, D. Thakur, R. Basu Beck, D. Bischoff, C. Bock, J. J. Boenish, H.
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We present results from an analysis of all data taken by the BICEP2, Keck Array and BICEP3 CMB polarization experiments up to and including the 2018 observing season. We add additional Keck Array observations at 220 GHz and BICEP3 observations at 95 GHz to the previous 95/150/220 GHz data set. The $Q/U$ maps now reach depths of 2.8, 2.8 and 8.8 $\m...

Fumagalli, Jacopo Renaux-Petel, Sébastien Witkowski, Lukas T.

We identify a characteristic pattern in the scalar-induced stochastic gravitational wave background from particle production during inflation. If particle production is sufficiently efficient, the scalar power spectrum exhibits $\mathcal{O}(1)$ oscillations periodic in $k$, characteristic of a sharp feature, with an exponentially enhanced envelope....

Galeev, Rafkat Muharlyamov, Ruslan Starobinsky, Alexei A. Sushkov, Sergey V. Volkov, Mikhail S.

It was found recently that the anisotropies in the homogeneous Bianchi I cosmology considered within the context of a specific Horndeski theory are damped near the initial singularity instead of being amplified. In this work we extend the analysis of this phenomenon to cover the whole of the Horndeski family. We find that the phenomenon is absent i...