Results 41 to 50 of about 6,253,661 (292)

Stable Wormholes in the Background of an Exponential f(R) Gravity

Universe, 2020
The current paper is devoted to investigating wormhole solutions with an exponential gravity model in the background of f ( R ) theory. Spherically symmetric static spacetime geometry is chosen to explore wormhole solutions with anisotropic fluid
Ghulam Mustafa, Ibrar Hussain, M. Farasat Shamir   +2 more
doaj   +1 more source

Phase transformations and vibrational properties of hybrid organic–inorganic perovskite MAPbI3 bulk at high pressure

Scientific Reports, 2023
The structural stability and internal properties of hybrid organic–inorganic perovskites (HOIPs) have been widely investigated over the past few years. The interplay between organic cations and inorganic framework is one of the prominent features. Herein
Ardimas, Teerachote Pakornchote, Wiwittawin Sukmas, Sojiphong Chatraphorn, Stewart J. Clark, Thiti Bovornratanaraks   +5 more
doaj   +1 more source

Cylindrical thin-shell wormholes and energy conditions [PDF]

, 2012
We prove the impossibility of cylindrical thin-shell wormholes supported by matter satisfying the energy conditions everywhere, under reasonable assumptions about the asymptotic behaviour of the - in general different - metrics at each side of the throat.
CLAUDIO SIMEONE, Darmois G., Lanczos K., Sen N., Visser M.   +4 more
core   +2 more sources

Energy conditions in f(P) gravity [PDF]

International Journal of Modern Physics D, 2022
[Formula: see text] gravity is a novel extension of Einsteinian cubic gravity in which the Ricci scalar in the action is replaced by a function of the curvature invariant [Formula: see text] which represents the contractions of the Riemann tensor at the cubic order [C. Erices, E. Papantonopoulos and E. N. Saridakis, Phys. Rev.
openaire   +2 more sources

A Proposal of a Regular Black Hole Satisfying the Weak Energy Condition

Galaxies, 2018
We discuss a black hole generated by some matter fluid, whose stress-energy tensor is known. We show that it is regular and that it satisfies the Weak Energy Condition (WEC) and the null energy condition (NEC).
Stefano Chinaglia
doaj   +1 more source

Electrically controlled superconductor-to-failed insulator transition and giant anomalous Hall effect in kagome metal CsV3Sb5 nanoflakes

Nature Communications, 2023
Kagome metals continue to attract interest due to the coexistence of electronic correlations and band topology. Here the authors use proton gating to modulate disorder and carrier density in CsV3Sb5 nanoflakes, and show its effect on superconductivity ...
Guolin Zheng, Cheng Tan, Zheng Chen, Maoyuan Wang, Xiangde Zhu, Sultan Albarakati, Meri Algarni, James Partridge, Lawrence Farrar, Jianhui Zhou, Wei Ning, Mingliang Tian, Michael S. Fuhrer, Lan Wang   +13 more
doaj   +1 more source

Cosmological milestones and energy conditions

, 2006
Until recently, the physically relevant singularities occurring in FRW cosmologies had traditionally been thought to be limited to the "big bang", and possibly a "big crunch".
Barrow J D, Barrow J D, C Cattoën, Caldwell R R, Cattoen C, Lake K, M Visser, Misner C W, Visser M   +8 more
core   +2 more sources

Energy conditions outside a dielectric ball

, 2004
We show analytically that the vacuum electromagnetic stress-energy tensor outside a ball with constant dielectric constant and permeability always obeys the weak, null, dominant, and strong energy conditions.
Delia Schwartz-Perlov, K. A. Milton, K. A. Milton, Ken D. Olum, Noah Graham, V. M. Mostepanenko   +5 more
core   +1 more source

Traversable Kaluza–Klein Wormholes?

Universe
Various authors have suggested that Kaluza–Klein variants of traversable wormholes might to some extent ameliorate the defocussing properties (the curvature condition violations, and implied energy condition violations) inherent in positing the existence
Christopher Simmonds, Matt Visser
doaj   +1 more source

Phonon-mediated superconductivity in $${\text{Mg}}_{{1 - x}} {\text{Mo}}_{x} {\text{B}}_{2}$$ Mg 1 - x Mo x B 2 compounds: a crystal prediction via cluster expansion and particle-swarm optimization

Scientific Reports, 2023
Investigating superconductivity represents one of the most significant phenomena in the field of condensed matter physics. Our simulations aim to elucidate the structures in the metallic state of Mg1−xMoxB2, which is essential for predicting their ...
Prutthipong Tsuppayakorn-aek, Wei Luo, Rajeev Ahuja, Thiti Bovornratanaraks   +3 more
doaj   +1 more source