Related papers: Cosmological Standard Timers from Unstable Primord…
We propose that primordial black hole (PBH) binary systems can lead to standard timers in tracking the evolution of the Universe. Through gravitational waves from monochromatic PBH binaries, the probability distribution on major axis and…
Oscillating massive fields in the primordial universe can be used as Standard Clocks. The ticks of these oscillations induce features in the density perturbations, which directly record the time evolution of the scale factor of the…
In a perturbed Universe, comoving tracers on a two-dimensional surface of constant observed redshift are at different proper time since the Big Bang. For tracers whose age is known independently, one can measure these perturbations of the…
In the primordial universe, oscillations of heavy fields can be considered as standard clocks to measure the expansion or contraction history of the universe. Those standard clocks provide a model-independent way of distinguishing inflation…
The hypothesis of existence of primordial black holes with large masses (\geq 10^6 M\odot), formed at the earliest stages of the Universe evolution, is considered in the paper. The possibility does not contradict some theories, see e.g.…
Standard Clocks in the primordial epoch leave a special type of features in the primordial perturbations, which can be used to directly measure the scale factor of the primordial universe as a function of time a(t), thus discriminating…
Cosmological time crystals are created when a scalar field moves periodically through phase space in a spatially flat Friedmann-Robertson-Walker spacetime due to the presence of a limit cycle. All such cosmological time crystals in the…
A stationary line element of general relativity seems to be compatible to essential cosmological facts (though only as far as one can expect solving the nonlinear Einstein equations neglecting local cosmic evolution and all spatial…
The standard cosmological model is sufficiently well constrained that precise estimates can be provided for the redshift of various physically defined times in the chronology of the Universe. For example, it is well known that…
Since Hubble and Lamaitre's discovery of the expanding universe using galaxies till the recent discovery of the accelerating universe using standard candles, direct measurements of the evolution of the scale factor of the universe a(t) have…
Time is a parameter playing a central role in our most fundamental modelling of natural laws. Relativity theory shows that the comparison of times measured by different clocks depends on their relative motions and on the strength of the…
In this paper we discuss a possible cosmological time evolution of fundamental constants from the theoretical and experimental point of views. On the theoretical side, we explain that such a cosmological time evolution is actually something…
Production of high-energy gravitational objects is a common feature of gravitational theories. The primordial universe is a natural setting for the creation of black holes and other nonperturbative gravitational entities. Cosmic black holes…
Experimentally distinguishing different primordial universe paradigms that lead to the Big Bang model is an outstanding challenge in modern cosmology and astrophysics. We show that a generic type of signals that exist in primordial universe…
The cosmological applications of atomic clocks so far have been limited to searches of the uniform-in-time drift of fundamental constants. In this paper, we point out that a transient in time change of fundamental constants can be induced…
The residuals of the power spectra of WMAP and Planck's cosmic microwave background (CMB) anisotropies data are known to exhibit a few interesting anomalies at different scales with marginal statistical significance. Combining bottom-up and…
Classically oscillating massive fields can be used as "standard clocks" in the primordial universe. They generate features in primordial density perturbations that directly record the scale factor evolution a(t). Detecting and measuring…
Astronomical observations of recent years show that the universe at high redshifts about ten is densely populated by the early formed objects: bright galaxies, quasars, gamma-bursters, and contains a lot of metals and dust. Such rich early…
The origin of dark matter as a thermal relic offers a compelling way in which the early universe was initially populated by dark matter. Alternative explanations typically appear exotic compared to the simplicity of thermal production.…
Recent observations from the James Webb Space Telescope have identified a population of massive galaxy sources ($\mathrm{>10^{10}\ M_\odot}$) at $z>7-10$, formed less than 700 Myr after the Big Bang. Such massive galaxies do not have enough…