Zobrazeno 1 - 10
of 125
pro vyhledávání: '"Niemeyer, Jens"'
The post-inflationary Universe can pass through a long epoch of effective matter-dominated expansion. This era may allow for both the parametric amplification of initial fluctuations and the gravitational collapse of inflaton perturbations. We perfor
Externí odkaz:
http://arxiv.org/abs/2311.08780
Following inflation, the Universe may pass through an early matter-dominated phase supported by the oscillating inflaton condensate. Initially small fluctuations in the condensate grow gravitationally on subhorizon scales and can collapse to form non
Externí odkaz:
http://arxiv.org/abs/2212.00425
Autor:
Mtchedlidze, Salome, Domínguez-Fernández, Paola, Du, Xiaolong, Schmidt, Wolfram, Brandenburg, Axel, Niemeyer, Jens, Kahniashvili, Tina
Primordial magnetic fields (PMFs) are possible candidates for explaining the observed magnetic fields in galaxy clusters. Two competing scenarios of primordial magnetogenesis have been discussed in the literature: inflationary and phase-transitional.
Externí odkaz:
http://arxiv.org/abs/2210.10183
Autor:
Ellis, David, Marsh, David J. E., Eggemeier, Benedikt, Niemeyer, Jens, Redondo, Javier, Dolag, Klaus
The Peak-Patch algorithm is used to identify the densest minicluster seeds in the initial axion density field simulated from string decay. The fate of these dense seeds is found by tracking the subsequent gravitational collapse in cosmological $N$-bo
Externí odkaz:
http://arxiv.org/abs/2204.13187
The Universe may pass through an effectively matter-dominated epoch between inflation and Big Bang Nucleosynthesis during which gravitationally bound structures can form on subhorizon scales. In particular, the inflaton field can collapse into inflat
Externí odkaz:
http://arxiv.org/abs/2110.15109
Autor:
Schwabe, Bodo, Niemeyer, Jens C.
Fuzzy dark matter (FDM) made of ultra-light bosonic particles is a viable alternative to cold dark matter (CDM) with clearly distinguishable small-scale features in collapsed structures. On large scales, it behaves gravitationally like CDM deviating
Externí odkaz:
http://arxiv.org/abs/2110.09145
Publikováno v:
Phys. Rev. D 103, 063525 (2021)
The early Universe may have passed through an extended period of matter-dominated expansion following inflation and prior to the onset of radiation domination. Sub-horizon density perturbations grow gravitationally during such an epoch, collapsing in
Externí odkaz:
http://arxiv.org/abs/2011.13333
This work studies the formation and growth of boson stars and their surrounding miniclusters by gravitational condensation using non-linear dynamical numerical methods. Fully dynamical attractive and repulsive self-interactions are also considered fo
Externí odkaz:
http://arxiv.org/abs/2011.01333
Publikováno v:
Phys. Rev. D 102, 083518 (2020)
The distinctive effects of fuzzy dark matter are most visible at non-linear galactic scales. We present the first simulations of mixed fuzzy and cold dark matter, obtained with an extended version of the Nyx code. Fuzzy (or ultralight, or axion-like)
Externí odkaz:
http://arxiv.org/abs/2007.08256
Autor:
Niemeyer, Jens C.
Axion-like particle (ALP) dark matter shows distinctive behavior on scales where wavelike effects dominate over self-gravity. Ultralight axions are candidates for fuzzy dark matter (FDM) whose de Broglie wavelength in virialized halos reaches scales
Externí odkaz:
http://arxiv.org/abs/1912.07064