Results 61 to 70 of about 26,635,104 (298)
Ghost-free non-local F(R) gravity compatible with ACT
Physics Letters BWe confront the ghost-free non-local F(R) gravity theories with the latest Atacama Cosmology Telescope (ACT) constraints on the spectral index of the scalar perturbations and the updated constraints of Planck/BICEP on the tensor-to-scalar ratio.
Shin’ichi Nojiri +2 more
doaj +1 more source
SOME REMARKS ON f(R) THEORIES OF GRAVITY
International Journal of Modern Physics: Conference Series, 2011 In this paper, I make a brief review of f(R) theories and their shortcomings — with some emphasis on the latter. I constrain myself to f(R) theories, the current acceleration of the (homegeneous) universe and the metric formalism (except at the very end).
openaire +2 more sources
Observer‐Based Adaptive Event‐Triggered Tracking Control for Fuzzy TS Systems With Premise Mismatch
International Journal of Adaptive Control and Signal Processing, EarlyView.This paper presents an adaptive logistic event‐triggered observer‐based tracking controller for Takagi‐Sugeno fuzzy systems under constrained inputs and network delays. Leveraging a hybrid LMI and Secretary Bird Optimization approach, this strategy significantly minimizes communication overhead and computational burden while ensuring optimal reference ...
Oussama Djadane +3 more
wiley +1 more source
New effective coupled $$F(^{(4)}\!R,\varphi )$$ F ( ( 4 ) R , φ ) modified gravity from $$f(^{(5)}\!R)$$ f ( ( 5 ) R ) gravity in five dimensions [PDF]
, 2015 Using some ideas of the Wesson induced matter theory, we obtain a new kind of $$F(^{(4)}\!R,\varphi )$$ modified gravity theory as an effective four-dimensional (4D) theory derived from $$f(^{(5)}\!R)$$ gravity in five dimensions (5D).
José Edgar Madriz Aguilar
core +1 more source
Advanced Engineering Materials, EarlyView.A novel workflow for investigating hydride vapor phase epitaxy for GaN bulk crystal growth is proposed. It combines Design of experiments (DoE) with physical simulations of mass transport and crystal growth kinetics, serving as an intermediate step between DoE and experiments.
J. Tomkovič +7 more
wiley +1 more source
Axially symmetric solutions in Ricci-inverse modified gravity
European Physical Journal C: Particles and FieldsWe investigate a family of axial symmetry solution constructed in general relativity (GR) within the framework of Ricci-inverse (RI) gravity theory. In GR, these solutions admitted closed time-like curves at an instant of time from an initial spacelike ...
F. Ahmed +2 more
doaj +1 more source
Stellar equilibrium configurations of white dwarfs in the f(R, T) gravity
European Physical Journal C: Particles and Fields, 2017 In this work we investigate the equilibrium configurations of white dwarfs in a modified gravity theory, namely, f(R, T) gravity, for which R and T stand for the Ricci scalar and trace of the energy-momentum tensor, respectively.
G. A. Carvalho +6 more
doaj +1 more source
Junction Conditions in f(R) Theories of Gravity [PDF]
Progress of Theoretical Physics, 2008 18 ...
Deruelle, N., Sasaki, M., Sendouda, Y.
openaire +4 more sources
Self‐Cleaning Sensor Surfaces for Long‐Term Environmental Monitoring
Advanced Engineering Materials, EarlyView.Long‐term use of unattended outdoor sensors without soiling or biofouling is achieved through generation of a micro‐ and nanorough cuvette surface by combing hydrophobic nanoparticles with fluorinated polymers, crosslinked and surface‐attached through CHic chemistry. The coating demonstrates self‐cleaning behavior and prolonged outdoor stability, which
Sanam Kumari Rajak +4 more
wiley +1 more source
Accelerating electrically charged ModMax black hole solutions in F(R) gravity
European Physical Journal C: Particles and FieldsUsing the $$C-$$ C - metric in the context of F(R) gravity coupled with the ModMax nonlinear electromagnetic field (the $$F(R)-$$ F ( R ) - ModMax theory), we derive an exact black hole solution in a four-dimensional spacetime.
B. Eslam Panah, N. Heidari, Á. Rincón
doaj +1 more source