Pulsar timing array observations as possible hints for nonsingular cosmology
M Zhu, G Ye, Y Cai - The European Physical Journal C, 2023 - Springer
Recent pulsar timing array (PTA) experiments have reported strong evidence of the
stochastic gravitational wave background (SGWB). If interpreted as primordial gravitational …
stochastic gravitational wave background (SGWB). If interpreted as primordial gravitational …
Avoiding singularities in Lorentzian-Euclidean black holes: The role of atemporality
We investigate a Schwarzschild metric exhibiting a signature change across the event
horizon, which gives rise to what we term a Lorentzian-Euclidean black hole. The resulting …
horizon, which gives rise to what we term a Lorentzian-Euclidean black hole. The resulting …
Dynamical systems of modified Gauss–Bonnet gravity: cosmological implications
A Singh - The European Physical Journal C, 2025 - Springer
In this paper, we derive the field equations of modified Gauss–Bonnet gravity termed as f (R,
G) gravity for the non-flat Friedmann–Robertson–Walker (FRW) spacetime. We utilize the …
G) gravity for the non-flat Friedmann–Robertson–Walker (FRW) spacetime. We utilize the …
On a Schwarzschild-type defect wormhole
ZL Wang - arxiv preprint arxiv:2307.01678, 2023 - arxiv.org
We investigate a new type of Schwarzschild wormhole, which relies on a 3-dimensional
spacetime defect with degenerate metrics. This particular wormhole is a solution of the …
spacetime defect with degenerate metrics. This particular wormhole is a solution of the …
Bouncing cosmology from nonlinear dark energy with two cosmological constants
M Burkmar, M Bruni - Physical Review D, 2023 - APS
We explore the dynamics of Friedmann-Lemaître-Robertson-Walker (FLRW) cosmologies
which consist of dark matter, radiation, and dark energy with a quadratic equation of state …
which consist of dark matter, radiation, and dark energy with a quadratic equation of state …
On the propagation across the big bounce in an open quantum FLRW cosmology
E Battista, HC Steinacker - The European Physical Journal C, 2022 - Springer
The propagation of a scalar field in an open FLRW bounce-type quantum spacetime is
examined, which arises within the framework of the IKKT matrix theory. In the first part of the …
examined, which arises within the framework of the IKKT matrix theory. In the first part of the …
Radiation-dominated bouncing model with slow contraction and inflation
PAP Molinari, PCM Delgado, RF Pinheiro… - Physical Review D, 2024 - APS
A very simple nonsingular inflationary model is presented where the unique matter content
is a radiation fluid. The model slowly contracts from a very large, almost empty and flat …
is a radiation fluid. The model slowly contracts from a very large, almost empty and flat …
One-loop effective action of the IKKT model for cosmological backgrounds
E Battista, HC Steinacker - Journal of High Energy Physics, 2024 - Springer
A bstract We study cosmological solutions of the IKKT model with k=–1 FLWR geometry,
taking into account one-loop corrections. A previously discussed covariant quantum …
taking into account one-loop corrections. A previously discussed covariant quantum …
Tensor perturbations from bounce inflation scenario in f(Q) gravity
K Hu, T Paul, T Qiu - Science China Physics, Mechanics & Astronomy, 2024 - Springer
In this paper, we construct a bounce inflation cosmological scenario in the framework of the
modified symmetric teleparallel gravity, namely f (Q) theory, and investigate the tensor …
modified symmetric teleparallel gravity, namely f (Q) theory, and investigate the tensor …
Global phase space analysis for a class of single scalar field bouncing solutions in general relativity
We carry out a compact phase space analysis of a non-canonical scalar field theory whose
Lagrangian is of the form F (X)-V (ϕ) within general relativity. In particular, we focus on a …
Lagrangian is of the form F (X)-V (ϕ) within general relativity. In particular, we focus on a …