It is commonly assumed that the energy density of the Universe was dominated by radiation
between reheating after inflation and the onset of matter domination 54,000 years later. …

American history is basically a saga of people concerned with external voyages. At first the
exploration, exploitation, and settlement of a new continent occupied their attention. This was …

Farming was first introduced to Europe in the mid-seventh millennium bc, and was associated
with migrants from Anatolia who settled in the southeast before spreading throughout …

Background Data on the rate and severity of SARS-CoV-2 reinfections in real-world settings
are scarce and the effects of vaccine boosters on reinfection risk are unknown. Methods In a …

The guide, translated from Bulgarian, is designed for foreign language teachers using the
suggestopedic method to teach adults or children. The text is divided into two parts. The first …

Homogeneous oscillations of the inflaton after inflation can be unstable to small spatial
perturbations even without coupling to other fields. We show that for inflaton potentials∝| ϕ| 2 n …

We calculate the equation of state after inflation and provide an upper bound on the duration
before radiation domination by taking the nonlinear dynamics of the fragmented inflaton …

Scalar metric fluctuations generically source a spectrum of gravitational waves at second
order in perturbation theory, poising gravitational wave experiments as potentially powerful …

The narrow-line Seyfert 1 galaxy IRAS 13224−3809 has been observed with XMM–Newton
for 500 ks. The source is rapidly variable on time-scales down to a few 100 s. The spectrum …

In broad classes of inflationary models the period of accelerated expansion is followed by
fragmentation of the inflaton scalar field into localized, long-lived, and massive oscillon …