scholarly journals TACHYON FIELDS WITH EFFECTS OF QUANTUM MATTER IN AN ANTI-DE SITTER UNIVERSE

2005 ◽  
Vol 14 (08) ◽  
pp. 1439-1449 ◽  
Author(s):  
EMILIO ELIZALDE ◽  
JOHN QUIROGA HURTADO
Keyword(s):  
Perfect Fluid ◽  
Quantum Effects ◽  
Accelerated Expansion ◽  
Energy Conditions ◽  
De Sitter ◽  
Quantum Matter ◽  
Trace Anomaly ◽  
Sitter Universe ◽  
Proposed Model ◽  
De Sitter Universe

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. The influence exerted by the quantum effects and by the tachyon on the AdS space is studied. The radius corresponding to this universe is calculated and the effect of the tachyon potential is discussed, in particular, concerning the possibility to get an accelerated scale factor for the proposed model (which yields an accelerated expansion of the AdS type of universe). Fulfillment of the cosmological energy conditions in the model is also investigated.

scholarly journals PHANTOM AND QUANTUM MATTER IN AN ANTI DE SITTER UNIVERSE

2004 ◽  
Vol 19 (01) ◽  
pp. 29-36 ◽  
Author(s):  
EMILIO ElIZALDE ◽  
JOHN QUIROGA HURTADO
Keyword(s):  
Perfect Fluid ◽  
Quantum Effects ◽  
Energy Conditions ◽  
De Sitter ◽  
Quantum Matter ◽  
Trace Anomaly ◽  
Sitter Universe ◽  
De Sitter Universe ◽  
Phantom Matter

We consider an anti de Sitter universe filled by quantum CFT with classical phantom matter and perfect fluid. The model represents the combination of a trace-anomaly annihilated and a phantom driven anti de Sitter universes. The influence exerted by the quantum effects and phantom matter on the AdS space is discussed. Different energy conditions in this type of universe are investigated and compared with those for the corresponding model in a de Sitter universe.

scholarly journals COSMOLOGY IN SCALAR–TENSOR THEORY AND ASYMPTOTICALLY de SITTER UNIVERSE

2001 ◽  
Vol 16 (20) ◽  
pp. 1303-1313 ◽  
Author(s):  
A. A. SEN ◽  
S. SEN
Keyword(s):  
Accelerated Expansion ◽  
Late Time ◽  
Scalar Tensor Theory ◽  
Dilaton Field ◽  
De Sitter ◽  
Positive Cosmological Constant ◽  
Expansion Phase ◽  
Tensor Theory ◽  
Sitter Universe ◽  
De Sitter Universe

We have investigated the cosmological scenarios with a four-dimensional effective action which is connected with multidimensional, supergravity and string theories. The solution for the scale factor is such that initially universe undergoes a decelerated expansion but in late times it enters into the accelerated expansion phase. In fact, it asymptotically becomes a de Sitter universe. The dilaton field in our model is a decreasing function of time and it becomes a constant in late time resulting the exit from the scalar–tensor theory to the standard Einstein's gravity. Also the dilaton field results in the existence of a positive cosmological constant in late times.

scholarly journals CONICAL SINGULAR SOLUTIONS IN (2+1)-DIMENSIONAL GRAVITY EMPLOYING THE ADM CANONICAL FORMALISM

2003 ◽  
Vol 12 (04) ◽  
pp. 677-687 ◽  
Author(s):  
MASAKATSU KENMOKU ◽  
SATOKO UCHIDA ◽  
TOYOKI MATSUYAMA
Keyword(s):  
Topological Defect ◽  
Canonical Formalism ◽  
Quantum Effects ◽  
Conical Singularity ◽  
De Sitter ◽  
Einstein Theory ◽  
Sitter Universe ◽  
Dimensional Gravity ◽  
De Sitter Universe ◽  
De Broglie Bohm

Topological solutions in the (2+1)-dimensional Einstein theory of gravity are studied within the ADM canonical formalism. It is found that a conical singularity appears in the closed expanding de Sitter universe solution as a topological defect in the case of the Einstein theory with a cosmological constant. Quantum effects on the conical singularity are studied using the de Broglie-Bohm interpretation. Finite quantum tunneling effects are obtained for the closed de Sitter universe, while no quantum effects are obtained for an open universe.

scholarly journals VANISHING COSMOLOGICAL CONSTANT IN MODIFIED GAUSS–BONNET GRAVITY WITH CONFORMAL ANOMALY

2007 ◽  
Vol 16 (05) ◽  
pp. 817-825 ◽  
Author(s):  
IVER BREVIK ◽  
JOHN QUIROGA
Keyword(s):  
General Relativity ◽  
Dark Energy ◽  
Cosmological Constant ◽  
Arbitrary Function ◽  
Modified Gravity ◽  
Quantum Effects ◽  
Conformal Anomaly ◽  
De Sitter ◽  
Sitter Universe ◽  
De Sitter Universe

We consider dark energy cosmology in a de Sitter universe filled with quantum conformal matter. Our model represents a Gauss–Bonnet model of gravity with contributions from quantum effects. To the General Relativity action an arbitrary function of the GB invariant, f(G), is added, and taking into account quantum effects from matter the cosmological constant is studied. For the considered model, the conditions for a vanishing cosmological constant are considered. Creation of a de Sitter universe by quantum effects in a GB modified gravity is discussed.

scholarly journals Scalar pair production in a magnetic field in de Sitter universe

2018 ◽  
Vol 78 (5) ◽  
Author(s):  
Mihaela-Andreea Băloi ◽  
Cosmin Crucean ◽  
Diana Popescu
Keyword(s):  
Magnetic Field ◽  
Pair Production ◽  
De Sitter ◽  
Sitter Universe ◽  
De Sitter Universe

scholarly journals Quantum annihilation of Anti-de Sitter universe

2000 ◽  
Vol 475 (3-4) ◽  
pp. 247-252 ◽  
Author(s):  
Iver Brevik ◽  
Sergei D. Odintsov
Keyword(s):  
De Sitter ◽  
Sitter Universe ◽  
De Sitter Universe

Coupling between time reversal and the space-time symmetries of the de Sitter universe

1974 ◽  
Vol 9 (10) ◽  
pp. 2710-2716 ◽  
Author(s):  
Ronald L. Mallett ◽  
Gordon N. Fleming
Keyword(s):  
Time Reversal ◽  
Space Time ◽  
De Sitter ◽  
Sitter Universe ◽  
De Sitter Universe
Sign in / Sign up

Export Citation Format

Share Document