Results 61 to 70 of about 48,479 (254)
Inflationary cosmology in modified gravity theories
, 2015 We review inflationary cosmology in modified gravity such as $R^2$ gravity with its extensions in order to generalize the Starobinsky inflation model. In particular, we explore inflation realized by three kinds of effects: modification of gravity, the ...
Bamba, Kazuharu, Odintsov, Sergei D.
core +2 more sources
Tachyonic inflation in loop quantum cosmology
European Physical Journal C: Particles and Fields, 2019 A tachyon field might be responsible for cosmological inflation at an early time and contribute to cosmological dark matter at a later time. We investigate tachyonic inflation by analyzing a tachyon field with different potentials in the framework of ...
Kui Xiao
doaj +1 more source
A symmetric DBI action theory and its applications to inflationary cosmology
European Physical Journal C: Particles and Fields, 2021 The Dirac-Born-Infeld (DBI) field theory in string theory is important and can provide the field of the universe’s inflation. At the same time, it provides a causal mechanism for generating the original density perturbation, thereby providing the ...
Xiaokun Yang +2 more
doaj +1 more source
Towards a cosmological dual to inflation
Physical Review D, 2011 We derive all single-field cosmologies with unit sound speed that generate scale invariant curvature perturbations on a dynamical attractor background. We identify three distinct phases: slow-roll inflation; a slowly contracting adiabatic ekpyrotic phase, described by a rapidly-varying equation of state; and a novel adiabatic ekpyrotic phase on a ...
Khoury, Justin, Miller, Godfrey E.J.
openaire +5 more sources
The warm inflationary universe
, 2008 In the past decade, the importance of dissipation and fluctuation to inflationary dynamics has been realized and has led to a new picture of inflation called warm inflation.
Arjun Berera +8 more
core +1 more source
3D SR‐μXCT analysis for lithology detection: Application to Ryugu sample A0159
Meteoritics &Planetary Science, EarlyView.Abstract Extraterrestrial breccia samples are formed through impact‐related processes that combine the fragments of distinct lithologies. As such, they are valuable indicators of the complex formation and evolution history of planetesimals in our solar system.
Léna Jossé +9 more
wiley +1 more source
Starobinsky-Like Inflation and Running Vacuum in the Context of Supergravity
Universe, 2016 We describe the primeval inflationary phase of the early Universe within a quantum field theoretical (QFT) framework that can be viewed as the effective action of vacuum decay in the early times. Interestingly enough, the model accounts for the “graceful
Spyros Basilakos +2 more
doaj +1 more source
Expected value, to a point: Moral decision‐making under background uncertainty
Noûs, EarlyView.Abstract Expected value maximization gives plausible guidance for moral decision‐making under uncertainty in many situations. But it has unappetizing implications in ‘Pascalian’ situations involving tiny probabilities of extreme outcomes. This paper shows, first, that under realistic levels of ‘background uncertainty’ about sources of value independent
Christian Tarsney
wiley +1 more source
Is the spectrum of gravitational waves the “Holy Grail” of inflation?
European Physical Journal C: Particles and Fields, 2019 It is often said that detecting a spectrum of primordial gravitational waves via observing B-mode polarization of the Cosmic Microwave Background is the “Holy Grail” of inflation.
Robert H. Brandenberger
doaj +1 more source
Lessons from the void: What Boltzmann brains teach
Analytic Philosophy, EarlyView.Abstract Some physical theories predict that almost all brains in the universe are Boltzmann brains, that is, short‐lived disembodied brains that are accidentally assembled as a result of thermodynamic or quantum fluctuations. Physicists and philosophers of physics widely regard this proliferation as unacceptable, and so take its prediction as a basis ...
Bradford Saad
wiley +1 more source