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200 papers

The field of exoplanet research has revitalized interest in M dwarfs, which have become favorite targets of Doppler and transit surveys. Accurate measurements of their basic properties such as masses, radii, and effective temperatures have…

Solar and Stellar Astrophysics · Physics 2015-06-11 Guillermo Torres

We propose a novel dark matter (DM) scenario based on a first-order phase transition in the early universe. If dark fermions acquire a huge mass gap between true and false vacua, they can barely penetrate into the new phase. Instead, they…

High Energy Physics - Phenomenology · Physics 2020-10-28 Jeong-Pyong Hong , Sunghoon Jung , Ke-Pan Xie

For non-relativistic thermal dark matter, close-to-threshold effects largely dominate the evolution of the number density for most of the times after thermal freeze-out, and hence affect the cosmological relic density. A precise evaluation…

High Energy Physics - Phenomenology · Physics 2024-07-01 Simone Biondini , Nora Brambilla , Gramos Qerimi , Antonio Vairo

The behavior of a decoupled ideal Fermi gas in a homogeneously expanding three-dimensional volume is investigated, starting from an equilibrium spectrum. In case the gas is massless and/or completely degenerate, the spectrum of the gas can…

Cosmology and Nongalactic Astrophysics · Physics 2017-03-16 Andreas Trautner

The kinetic theory of the Fermi liquid is applied to finite nuclei. The nuclear collective motion is treated in terms of the observable variables: particle density, current density, pressure etc. The nuclear dynamics is influenced strongly…

Nuclear Theory · Physics 2007-05-23 V. M. Kolomietz

We study propagation of light in a Fermi-Dirac gas at zero temperature. We analytically obtain the leading density correction to the optical linewidth. This correction is a direct consequence of the quantum statistical correlations of…

Statistical Mechanics · Physics 2009-10-31 J. Ruostekoski , J. Javanainen

We study the decoupling process of neutrinos in the early universe in the presence of three-flavour oscillations. The evolution of the neutrino spectra is found by solving the corresponding momentum-dependent kinetic equations for the…

High Energy Physics - Phenomenology · Physics 2016-07-29 Pablo F. de Salas , Sergio Pastor

Recent work on increasing the effective number of neutrino species (Neff) in the early universe has focussed on introducing extra relativistic species (`dark radiation'). We draw attention to another possibility: a new particle of mass less…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 Celine Boehm , Matthew J. Dolan , Christopher McCabe

Various quantities of an attractively interacting fermion system at the unitary limit are determined by extrapolating Monte Carlo results of low-density neutron matter. Smooth extrapolation in terms of $1/(k_F a_0)$ ($k_F$ is the Fermi…

Nuclear Theory · Physics 2009-11-25 T. Abe , R. Seki

The early kinetic decoupling (eKD) effect is an inevitable ingredient in calculating the relic density of dark matter (DM) for various well-motivated scenarios. It appears naturally in forbidden dark matter annihilation, the main focus of…

High Energy Physics - Phenomenology · Physics 2023-06-14 Yu Liu , Xuewen Liu , Bin Zhu

The connection between cosmological observations and neutrino physics is discussed in detail. Neutrinos decouple from thermal contact in the early Universe at a temperature of order 1 MeV which coincides with the temperature where light…

High Energy Physics - Phenomenology · Physics 2008-11-26 Steen Hannestad

The relic abundance of Dark Matter (DM) produced via thermal freeze-in is sensitive to the thermal history during and after cosmic reheating. In minimal models, this opens up the possibility to make predictions for collider observables by…

High Energy Physics - Phenomenology · Physics 2026-04-20 Marco Drewes , Yannis Georis , Mubarak A. S. Mohammed , Sebastian Zell

In this paper we consider the Fermi's paradox (FP) and propose a possible resolution in the context of super-advanced alien civilizations. In this sense it can be regarded as to be the weak Fermi paradox (WFP). By assuming that…

Popular Physics · Physics 2021-04-09 Zaza Osmanov

The dark matter relic density is being increasingly precisely measured. This relic density is theoretically determined by a Boltzmann equation which computes the dark matter distribution according to the (thermally averaged) cross section…

High Energy Physics - Phenomenology · Physics 2025-06-30 Prabhat Butola , D. Indumathi , Pritam Sen

If the early universe is dominated by an energy density which evolves other than radiation-like the normal Hubble-temperature relation $H\propto T^2$ is broken and dark matter relic density calculations in this era can be significantly…

High Energy Physics - Phenomenology · Physics 2025-11-06 Carlos Maldonado , James Unwin

We study a nonstandard dark-matter thermal history in which strong self-interactions give rise to collective many-body effects at high number density, as in strongly interacting quantum media. At early times, dark matter occupies a…

High Energy Physics - Phenomenology · Physics 2026-03-11 Hindi Zouhair

If neutrinos are Dirac particles the existence of light right-handed neutrinos $\nu_{R}$ is implied. Those would contribute to the effective number of relativistic neutrino species $N_{{\rm eff}}$ in the early Universe. With pure standard…

High Energy Physics - Phenomenology · Physics 2020-07-01 Xuheng Luo , Werner Rodejohann , Xun-Jie Xu

We compute the equation of state, the gap as well as the density fluctuations of a two-component superfluid Fermi gas over the whole range of BEC-BCS crossover at vanishing temperature within the functional renormalisation group approach.…

Quantum Gases · Physics 2023-07-28 Bruno M. Faigle-Cedzich , Jan M. Pawlowski , Christof Wetterich

In this chapter we focus first on the theoretical methods and relevant computational approaches to calculate the electronic structure of atoms, molecules, and clusters containing heavy elements for which relativistic effects become…

Chemical Physics · Physics 2021-10-05 Simone Taioli , Stefano Simonucci

In cold atoms and in the crust of neutron stars the pairing gap can reach values comparable with the Fermi energy. While in nuclei the neutron gap is smaller, it is still of the order of a few percent of the Fermi energy. The pairing…

Nuclear Theory · Physics 2021-12-28 Aurel Bulgac