Results 51 to 60 of about 42,432 (292)
Mass in de Sitter and Anti-de Sitter Universes with Regard to Dark Matter [PDF]
Universe, 2020 An explanation of the origin of dark matter is suggested in this work. The argument is based on symmetry considerations about the concept of mass. In Wigner’s view, the rest mass and the spin of a free elementary particle in flat space-time are the two invariants that characterize the associated unitary irreducible representation of the Poincaré group.
openaire +3 more sources
Photon decaying in de Sitter universe [PDF]
Journal of Theoretical and Applied Physics, 2019 AbstractThe interaction between three photons is studied in de Sitter ambient space formalism. As a special case, the half harmonic generator is considered, i.e., one photon decays to two same-energy photons. The scattering matrix elements are presented which define the indirect gravitational effect on quantum field theory.
Y. Ahmadi, M. V. Takook
openaire +2 more sources
Stringy Bubbles Solve de Sitter Troubles
Universe, 2021 Finding four-dimensional de Sitter spacetime solutions in string theory has been a vexing quest ever since the discovery of the accelerating expansion of the universe.
Per Berglund +2 more
doaj +1 more source
Distinguishing de Sitter universe from thermal Minkowski spacetime by Casimir-Polder-like force [PDF]
, 2014 We demonstrate that the static ground state atom, which interacts with a conformally coupled massless scalar field in the de Sitter invariant vacuum, can obtain a position-dependent energy-level shift and this shift could cause a Casimir-Polder-like ...
Jing, Jiliang, Tian, Zehua
core +2 more sources
Tachyon fields with effects of quantum matter in an Anti-de Sitter Universe
, 2004 We consider an Anti-de Sitter universe filled by quantum conformal matter with the contribution from the usual tachyon and a perfect fluid. The model represents the combination of a trace-anomaly annihilated and a tachyon driven Anti-de Sitter universe ...
Abramo L. R. W. +18 more
core +2 more sources
Uniformly accelerating black holes in a de Sitter universe [PDF]
, 2000 A class of exact solutions of Einstein's equations is analysed which describes uniformly accelerating charged black holes in an asymptotically de Sitter universe. This is a generalisation of the C-metric which includes a cosmological constant.
B. Carter +11 more
core +2 more sources
Journal of High Energy Physics, 2021 We consider black holes in 2d de Sitter JT gravity coupled to a CFT, and entangled with matter in a disjoint non-gravitating universe. Tracing out the entangling matter leaves the CFT in a density matrix whose stress tensor backreacts on the de Sitter ...
Vijay Balasubramanian +2 more
doaj +1 more source
Tracking our Universe to de Sitter by a Horndeski scalar
, 2017 Assuming both that our Universe is evolving into a de Sitter space and a vanishing cosmological constant, leaves only the option that the observed acceleration is provided by a "kinetic" energy of a scalar field.
Germani, Cristiano, Martin-Moruno, Prado
core +1 more source
Bubbles created from vacuum fluctuation [PDF]
, 2001 We show that the bubbles $S^2\times S^2$can be created from vacuum fluctuation in certain De Sitter universe, so the space-time foam-like structure might really be constructed from bubbles of $S^2\times S^2$ in the very early inflating phase of our ...
Birrell N D +4 more
core +3 more sources
Pediatric Blood &Cancer, EarlyView.ABSTRACT Neuroblastoma is the most common extracranial solid tumor in early childhood. Its clinical behavior is highly variable, ranging from spontaneous regression to fatal outcome despite intensive treatment. The International Society of Pediatric Oncology Europe Neuroblastoma Group (SIOPEN) Radiology and Nuclear Medicine Specialty Committees ...
Annemieke Littooij +11 more
wiley +1 more source