scholarly journals Unimodular vs nilpotent superfield approach to pure dS supergravity

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Sukruti Bansal ◽  
Silvia Nagy ◽  
Antonio Padilla ◽  
Ivonne Zavala
Keyword(s):  
String Theory ◽  
General Framework ◽  
Recent Progress ◽  
High Energy ◽  
De Sitter Spacetime ◽  
De Sitter ◽  
New Approach ◽  
Sitter Spacetime ◽  
Novel Approach ◽  
De Sitter Vacua

Abstract Recent progress in understanding de Sitter spacetime in supergravity and string theory has led to the development of a four dimensional supergravity with spontaneously broken supersymmetry allowing for de Sitter vacua, also called de Sitter supergravity. One approach makes use of constrained (nilpotent) superfields, while an alternative one couples supergravity to a locally supersymmetric generalization of the Volkov-Akulov goldstino action. These two approaches have been shown to give rise to the same 4D action. A novel approach to de Sitter vacua in supergravity involves the generalisation of unimodular gravity to supergravity using a super-Stückelberg mechanism. In this paper, we make a connection between this new approach and the previous two which are in the context of nilpotent superfields and the goldstino brane. We show that upon appropriate field redefinitions, the 4D actions match up to the cubic order in the fields. This points at the possible existence of a more general framework to obtain de Sitter spacetimes from high-energy theories.

scholarly journals Dark energy and quantum gravity

2019 ◽  
Vol 28 (14) ◽  
pp. 1944018 ◽  
Author(s):  
Per Berglund ◽  
Tristan Hübsch ◽  
Djordje Minić
Keyword(s):  
Dark Energy ◽  
String Theory ◽  
Quantum Gravity ◽  
Cosmological Constant ◽  
Particle Physics ◽  
Dual Space ◽  
Planck Scale ◽  
De Sitter Spacetime ◽  
De Sitter ◽  
Sitter Spacetime

Realizing dark energy and the observed de Sitter spacetime in quantum gravity has proven to be obstructed in almost every usual approach. We argue that additional degrees of freedom of the left- and right-movers in string theory and a resulting doubled, noncommutatively generalized geometric formulation thereof can lead to an effective model of dark energy consistent with de Sitter spacetime. In this approach, the curvature of the canonically conjugate dual space provides for the dark energy inducing a positive cosmological constant in the observed spacetime, whereas the size of the above dual space is the gravitational constant in the same observed de Sitter spacetime. As a hallmark relation owing to a unique feature of string theory which relates short distances to long distances, the cosmological constant scale, the Planck scale and the effective TeV-sized particle physics scale must satisfy a see-saw-like formula — precisely the generic prediction of certain stringy cosmic brane type models.

scholarly journals GALILEAN TYPE IIA BACKGROUNDS AND A MAP

2011 ◽  
Vol 26 (19) ◽  
pp. 1443-1451 ◽  
Author(s):  
HARVENDRA SINGH
Keyword(s):  
String Theory ◽  
Point Of View ◽  
De Sitter Spacetime ◽  
De Sitter ◽  
Dynamical Exponent ◽  
Four Dimensions ◽  
Sitter Spacetime ◽  
M Theory

We study nonrelativistic AdS4×CP3 solutions with dynamical exponent 3 in type IIA string theory, both with and without Romans mass. The compactifications to four dimensions are found to describe Proca fields in anti-de Sitter spacetime. This leads us to conclude that the massive and massless IIA theories should be identified in four dimensions and the Romans' mass should be identified with the "flux" along CP3. From supergravity point of view, it suggests a four-dimensional symmetry that rotates Romans mass into the flux along CP3. We also identify M-theory Galilean (ABJM) background which gives rise to the nonrelativistic type IIA solution.

scholarly journals Emergent $$\alpha $$-like fermionic vacuum structure and entanglement in the hyperbolic de Sitter spacetime

2019 ◽  
Vol 79 (9) ◽  
Author(s):  
Sourav Bhattacharya ◽  
Shankhadeep Chakrabortty ◽  
Shivang Goyal
Keyword(s):  
Quantum Correlations ◽  
Dirac Field ◽  
De Sitter Spacetime ◽  
De Sitter ◽  
Local Modes ◽  
Vacuum Structure ◽  
Continuous Parameter ◽  
Sitter Spacetime ◽  
Global Modes ◽  
De Sitter Vacua

Abstract We report a non-trivial feature of the vacuum structure of free massive or massless Dirac fields in the hyperbolic de Sitter spacetime. Here we have two causally disconnected regions, say R and L separated by another region, C. We are interested in the field theory in $$R\cup L$$R∪L to understand the long range quantum correlations between R and L. There are local modes of the Dirac field having supports individually either in R or L, as well as global modes found via analytically continuing the R modes to L and vice versa. However, we show that unlike the case of a scalar field, the analytic continuation does not preserve the orthogonality of the resulting global modes. Accordingly, we need to orthonormalise them following the Gram–Schmidt prescription, prior to the field quantisation in order to preserve the canonical anti-commutation relations. We observe that this prescription naturally incorporates a spacetime independent continuous parameter, $$\theta _{\mathrm{RL}}$$θRL, into the picture. Thus interestingly, we obtain a naturally emerging one-parameter family of $$\alpha $$α-like de Sitter vacua. The values of $$\theta _{\mathrm{RL}}$$θRL yielding the usual thermal spectra of massless created particles are pointed out. Next, using these vacua, we investigate both entanglement and Rényi entropies of either of the regions and demonstrate their dependence on $$\theta _{\mathrm{RL}}$$θRL.

scholarly journals Refining the boundaries of the classical de Sitter landscape

2017 ◽  
Vol 2017 (3) ◽  
Author(s):  
David Andriot ◽  
Johan Blåbäck
Keyword(s):  
String Theory ◽  
Compact Manifold ◽  
Cosmological Models ◽  
Ricci Scalar ◽  
General Interest ◽  
De Sitter Spacetime ◽  
Type Ii ◽  
De Sitter ◽  
Technical Aspects ◽  
Sitter Spacetime

Abstract We derive highly constraining no-go theorems for classical de Sitter backgrounds of string theory, with parallel sources; this should impact the embedding of cosmological models. We study ten-dimensional vacua of type II supergravities with parallel and backreacted orientifold O p -planes and D p -branes, on four-dimensional de Sitter spacetime times a compact manifold. Vacua for p = 3, 7 or 8 are completely excluded, and we obtain tight constraints for p = 4, 5, 6. This is achieved through the derivation of an enlightening expression for the four-dimensional Ricci scalar. Further interesting expressions and no-go theorems are obtained. The paper is self-contained so technical aspects, including conventions, might be of more general interest.

scholarly journals Logarithmic loop corrections, moduli stabilisation and de Sitter vacua in string theory

2020 ◽  
Vol 2020 (1) ◽  
Author(s):  
Ignatios Antoniadis ◽  
Yifan Chen ◽  
George K. Leontaris
Keyword(s):  
String Theory ◽  
De Sitter ◽  
De Sitter Vacua

scholarly journals Wavefunctions in dS/CFT revisited: principal series and double-trace deformations

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Hiroshi Isono ◽  
Hoiki Madison Liu ◽  
Toshifumi Noumi
Keyword(s):  
Principal Series ◽  
Light Fields ◽  
Quadratic Term ◽  
De Sitter Spacetime ◽  
Cosmological Horizon ◽  
De Sitter ◽  
Complementary Series ◽  
Point Function ◽  
Sitter Spacetime ◽  
Simple Scaling

Abstract We study wavefunctions of heavy scalars on de Sitter spacetime and their implications to dS/CFT correspondence. In contrast to light fields in the complementary series, heavy fields in the principal series oscillate outside the cosmological horizon. As a consequence, the quadratic term in the wavefunction does not follow a simple scaling and so it is hard to identify it with a conformal two-point function. In this paper, we demonstrate that it should be interpreted as a two-point function on a cyclic RG flow which is obtained by double-trace deformations of the dual CFT. This is analogous to the situation in nonrelativistic AdS/CFT with a bulk scalar whose mass squared is below the Breitenlohner-Freedman (BF) bound. We also provide a new dS/CFT dictionary relating de Sitter two-point functions and conformal two-point functions in the would-be dual CFT.

scholarly journals Interacting quantum fields in various charts of anti–de Sitter spacetime

2021 ◽  
Vol 103 (4) ◽  
Author(s):  
E. T. Akhmedov ◽  
A. A. Artemev ◽  
I. V. Kochergin
Keyword(s):  
De Sitter Spacetime ◽  
Quantum Fields ◽  
De Sitter ◽  
Sitter Spacetime
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