scholarly journals Cosmological constant, brane tension and large hierarchy in a generalized Randall-Sundrum braneworld scenario

2008 ◽  
Vol 2008 (05) ◽  
pp. 042-042 ◽  
Author(s):  
Saurya Das ◽  
Debaprasad Maity ◽  
Soumitra SenGupta
Keyword(s):  
Cosmological Constant ◽  
Brane Tension ◽  
Large Hierarchy

scholarly journals VANISHING OF THE COSMOLOGICAL CONSTANT, STABILITY OF THE DILATON AND INFLATION

1996 ◽  
Vol 05 (05) ◽  
pp. 567-578
Author(s):  
A. DE LA MACORRA
Keyword(s):  
Cosmological Constant ◽  
Vacuum Energy ◽  
Scalar Potential ◽  
Suitable Choice ◽  
Dilaton Field ◽  
String Models ◽  
Large Hierarchy ◽  
Chiral Potential

We study the possibility of canceling the cosmological constant in supergravity string models. We show that with a suitable choice of superpotential the vacuum energy may vanish with the dilaton field at its minimum and supersymmetry broken with a large hierarchy. We derive the condition for which the introduction of a chiral potential, e.g. the inflaton potential, does not destabilize the dilaton field even in the region where the scalar potential takes positive values. This allows for an inflationary potential with the dilaton frozen at its minimum.

scholarly journals GENERALISED COSMOLOGY OF CODIMENSION-TWO BRANEWORLDS

2004 ◽  
Vol 19 (31) ◽  
pp. 5295-5302 ◽  
Author(s):  
JÉRÉMIE VINET
Keyword(s):  
Cosmological Constant ◽  
Static Solution ◽  
Brane Tension ◽  
Cosmological Constant Problem ◽  
Brane Model ◽  
Codimension Two ◽  
Hubble Rate ◽  
Tuning Mechanism ◽  
Self Tuning ◽  
Promising Line

It has recently been argued that codimension-two braneworlds offer a promising line of attack on the cosmological constant problem, since in such models the Hubble rate is not directly related to the brane tension. We point out challenges to building more general models where the brane content is not restricted to pure tension. In order to address these challenges, we construct a thick brane model which we linearize around a well known static solution. We show that the model's cosmology does reduce to standard FRW behaviour, but find no hint of a self-tuning mechanism which might help solve the cosmological constant problem whithin the context of non-supersymmetric Einstein gravity.

scholarly journals HOLOGRAPHIC ENTROPY ON THE BRANE IN de SITTER SCHWARZSCHILD SPACE

2002 ◽  
Vol 17 (01) ◽  
pp. 51-58 ◽  
Author(s):  
SACHIKO OGUSHI
Keyword(s):  
Black Hole ◽  
Cosmological Constant ◽  
Black Hole Entropy ◽  
Brane Tension ◽  
De Sitter ◽  
Schwarzschild Black Hole ◽  
Verlinde Formula ◽  
The Relationship ◽  
Friedmann Robertson Walker ◽  
Schwarzschild Background

The relationship between the entropy of de Sitter (dS) Schwarzschild space and that of the CFT, which lives on the brane, is discussed by using Friedmann–Robertson–Walker (FRW) equations and Cardy–Verlinde formula. The cosmological constant appears on the brane with time-like metric in dS Schwarzschild background. On the other hand, in case of the brane with space-like metric in dS Schwarzschild background, the cosmological constant of the brane does not appear because we can choose brane tension to cancel it. We show that when the brane crosses the horizon of dS Schwarzschild black hole, both for time-like and space-like cases, the entropy of the CFT exactly agrees with the black hole entropy of five-dimensional dS background as it happens in the AdS/CFT correspondence.

scholarly journals Toward Solving the Cosmological Constant Problem?

2003 ◽  
Vol 18 (18) ◽  
pp. 3221-3262 ◽  
Author(s):  
Olindo Corradini ◽  
Alberto Iglesias ◽  
Zurab Kakushadze
Keyword(s):  
Cosmological Constant ◽  
Extra Dimensions ◽  
Brane World ◽  
Infinite Volume ◽  
Brane Tension ◽  
Smooth Solutions ◽  
Cosmological Constant Problem ◽  
World Volume

We discuss the cosmological constant problem in the context of higher codimension brane world scenarios with infinite-volume extra dimensions. In particular, by adding higher curvature terms in the bulk action we are able to find smooth solutions with the property that the four-dimensional part of the brane world-volume is flat for a range of positive values of the brane tension.

REALISTIC HIERARCHIES FROM THE SUPERSTRING

1989 ◽  
Vol 04 (02) ◽  
pp. 411-426 ◽  
Author(s):  
G. D. COUGHLAN
Keyword(s):  
Field Theory ◽  
Cosmological Constant ◽  
Parameter Space ◽  
Low Energy ◽  
Heterotic String ◽  
Large Region ◽  
World Sheet ◽  
Dimensional Theory ◽  
Vacuum States ◽  
Large Hierarchy

A simple phenomenological parametrization of the four-dimensional field theory arising from compactification of the ten-dimensional heterotic string is considered. Possible vacuum states of the four-dimensional theory are examined in the context of the "model" low-energy Lagrangian proposed by Witten. A large hierarchy between MP and m3/2 arises naturally for a large region of parameter space, with the compactification scale typically 0(1 − 10−2)and a vanishing cosmological constant. The presence of E6 singlet superfields with large nonperturbative masses (coming from world-sheet instantons) can drastically alter the hierarchy in certain cases, but nonetheless leads to acceptable low-energy phenomenology.

Cosmological constant

2018 ◽  
Author(s):  
Michael Kachelriess
Keyword(s):  
Dark Energy ◽  
Cosmological Constant ◽  
Accelerated Expansion ◽  
Vacuum Fluctuations ◽  
Present Epoch ◽  
Modify Gravity ◽  
Expansion Of The Universe ◽  
The Universe

The contribution of vacuum fluctuations to the cosmological constant is reconsidered studying the dependence on the used regularisation scheme. Then alternative explanations for the observed accelerated expansion of the universe in the present epoch are introduced which either modify gravity or add a new component of matter, dubbed dark energy. The chapter closes with some comments on attempts to quantise gravity.

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