Results 41 to 50 of about 59,420 (206)

On Non-Gaussianity in the Curvaton Scenario [PDF]

, 2003
Since a positive future detection of non-linearity in the cosmic microwave background anisotropy pattern might allow to descriminate among different mechanisms giving rise to cosmological adiabatic perturbations, we study the evolution of the second ...
A. D. Linde, A. Guth, A. Guth, A. Riotto, A. Starobinsky, C. L. Bennett, C. L. Bennett, C. P. Ma, D. H. Lyth, D. H. Lyth, D. H. Lyth, D. H. Lyth, D. Wands, E. Komatsu, E. Komatsu, F. Bernardeau, G. Dvali, G. F. Smoot, G. I. Rigopoulos, H. V. Peiris, J. Garcia-Bellido, J. M. Bardeen, J. M. Bardeen, J. Maldacena, K. A. Malik, K. Enqvist, K. M. Gorski, K. Nakamura, M. Rees, N. Bartolo, N. Bartolo, S. M. Leach, S. Matarrese, S. Matarrese, S. Mollerach, S. Mollerach, S. W. Hawking, T. Moroi, T. Moroi, T. Pyne, V. Acquaviva, V. Barger, V. F. Mukhanov, V. F. Mukhanov   +43 more
core   +2 more sources

‘Turkeys Cannot Vote for Christmas’: Why Epistemic Disobedience in an Anti‐Black World Matters

Australian Journal of Social Issues, EarlyView.
ABSTRACT Never in the history of global coloniality has the idea of epistemic disobedience been as important as in the 21st century. This is not only because the struggle for decolonisation has shifted from physical confrontation between the coloniser and the colonised into a battle of ideas but also because the former has deployed the idea of ...
Morgan Ndlovu
wiley   +1 more source

Appearances are deceptive: can graviton have a mass?

Journal of High Energy Physics
We study the dynamics of linear gravitational perturbations on cosmological backgrounds of massive fermionic fields. We observe that, when gravitational and matter action are expanded to quadratic order in gravitational perturbations on cosmological ...
Leihua Liu, Tomislav Prokopec
doaj   +1 more source

DENSITY PERTURBATIONS IN A REALISTIC UNIVERSE

Odessa Astronomical Publications, 2017
We analyze evolution of density perturbations in a flat or open universe filled in with matter, relativistic particles and possibly cosmological constant. Density perturbations grow very slowly in a universe filled in with low mass neutrinos.
M. Demianski, Z. Golda, A. Woszczyna
doaj   +1 more source

Generating cosmological perturbations in non-singular Horndeski cosmologies

Journal of High Energy Physics, 2023
We construct a concrete model of Horndeski bounce with strong gravity in the past. Within this model we show that the correct spectra of cosmological perturbations may be generated at early contracting epoch, with mild fine-tuning ensuring that the ...
Yulia Ageeva, Pavel Petrov, Valery Rubakov   +2 more
doaj   +1 more source

Quantum coherence of cosmological perturbations

, 2017
The degrees of quantum coherence of cosmological perturbations of different spins are computed in the large-scale limit and compared with the standard results holding for a single mode of the electromagnetic field in an optical cavity.
Giovannini, Massimo
core   +1 more source

Quantum GraviElectro Dynamics

Annalen der Physik, EarlyView.
The BRST invariant Lagrangian of the gravitationally interacting U(1)$U(1)$ gauge theory, namely the Quantum GraviElectro Dynamics (QGED). The Yan–Mills theory with the Hilbert–Einstein gravitational Lagrangian, namely the Yang–Mills–Utiyama (YMU) theory, is defined and quantised using the standard procedure. The theory is perturbatively renormalisable,
Yoshimasa Kurihara
wiley   +1 more source

The Stochastic‐Dissipative Störmer Problem‐Trajectories and Radiation Patterns

Annalen der Physik, EarlyView.
We consider charged particle motion and radiation in a dipole magnetic field, in the presence of friction and of stochastic forces. The numerical solutions of the Langevin equation reveal how these forces modify the complex dynamics of particles, and they offer some new insights into the nonlinear processes relevant to planetary radiation belts ...
Tiberiu Harko, Gabriela Raluca Mocanu
wiley   +1 more source

Hamiltonian Cosmological Perturbation Theory

, 2005
The Hamiltonian approach to cosmological perturbations in general relativity in finite space-time is developed, where a cosmological scale factor is identified with spatial averaging the metric determinant logarithm.
A.F. Zakharov, Arnowitt, B.M. Barbashov, Bajan, Bardeen, Behnke, Blaschke, Dirac, Dirac, Esposito-Farese, Fock, Kuchar, Lifshitz, Mukhanov, Pawlowski, Perlmutter, Riess, Riess, V.A. Zinchuk, V.N. Pervushin, Weinberg, York, Zelmanov, Zelmanov   +23 more
core   +1 more source

Logarithmic and Strong Coupling Models in Weyl‐Type f(Q,T)$f(Q,T)$ Gravity

Annalen der Physik, EarlyView.
This work explores Weyl‐type f(Q,T) gravity using recent observational datasets — CC, Pantheon+, Union 3.0, and DESI DR2. Through MCMC analysis of logarithmic and strong coupling models, the study reveals a transition from deceleration to acceleration, quintessence‐to‐phantom dynamics, and late‐time consistency with LCDM, offering a geometry‐driven ...
Rahul Bhagat, S. K. Tripathy, B. Mishra
wiley   +1 more source