# What if string theory has no de Sitter vacua

@article{Danielsson2018WhatIS, title={What if string theory has no de Sitter vacua}, author={Ulf H. Danielsson and Thomas Van Riet}, journal={arXiv: High Energy Physics - Theory}, year={2018} }

We present a brief overview of attempts to construct de Sitter vacua in string theory and explain how the results of this 20-year endeavor could point to the fact that string theory harbors no de Sitter vacua at all. Making such a statement is often considered controversial and "bad news for string theory". We discuss how perhaps the opposite can be true.

#### Figures from this paper

#### 246 Citations

De Sitter vs Quintessence in String Theory

- Physics
- 2018

De Sitter solutions have been recently conjectured to be incompatible with quantum gravity. In this paper we critically assess the progress and challenges of different mechanisms to obtain de Sitter… Expand

A Comment on Effective Field Theories of Flux Vacua

- Physics
- 2018

We discuss some basic aspects of effective field theory applied to supergravity theories which arise in the low-energy limit of string theory. Our discussion is particularly relevant to the effective… Expand

de Sitter extrema and the swampland

- Physics
- 2018

Recently it has been conjectured that string theory does not allow for dS vacua or dS extrema. To scrutinize such a conjecture, it is important to study concrete string theory compactifications and… Expand

No classical (anti-)de Sitter solutions with O8-planes

- Physics
- Physics Letters B
- 2019

Abstract It was recently proposed that type IIA string theory may allow classical de Sitter solutions with O8-planes as the only localized sources. We show that such solutions are incompatible with… Expand

On stringy de Sitter spacetimes

- Physics
- 2019

We reexamine a family of models with a 3+1-dimensional de Sitter spacetime obtained in the standard tree-level low-energy limit of string theory with a non-trivial anisotropic axion-dilaton… Expand

Open Problems on Classical de Sitter Solutions

- Physics, Mathematics
- Fortschritte der Physik
- 2019

Classical 10d string backgrounds with a 4d de Sitter space-time, D-brane and orientifold sources, are commonly believed to satisfy the following:
1. There is no classical de Sitter solution with… Expand

Stringy Bubbles Solve de Sitter Troubles

- Physics
- 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. Building on a recent analysis… Expand

A Note on the dS Swampland Conjecture, Non‐BPS Branes and K‐Theory

- Chemistry, Physics
- Fortschritte der Physik
- 2019

We point out that the de Sitter swampland conjecture would be falsified if classical fluxed Type IIA orientifold vacua with a single non-BPS D7-brane were indeed part of the string theory landscape.… Expand

Moduli stabilisation and inflation in type IIB/F-theory

- Physics
- Proceedings of Corfu Summer Institute 2018 "School and Workshops on Elementary Particle Physics and Gravity" — PoS(CORFU2018)
- 2019

In the first part of this talk, a short overview of the ongoing debate on the existence of de Sitter vacua in string theory is presented. In the second part, the moduli stabilisation and inflation… Expand

de Sitter vacua in the string landscape

- Physics
- 2019

The late-time behavior of our universe is one of accelerated expansion, or that of a de Sitter space, and therefore motivates us to look for time-dependent backgrounds. Finding such backgrounds in… Expand

#### References

SHOWING 1-10 OF 206 REFERENCES

Constraining de Sitter Space in String Theory.

- Physics, Medicine
- Physical review letters
- 2015

It is argued that the heterotic string does not have classical vacua corresponding to de Sitter space-times of dimension four or higher, and suggests that the genericity arguments used in string landscape discussions should be viewed with caution. Expand

A global view on the search for de Sitter vacua in (Type IIA) string theory

- Physics
- 2012

A bstractThe search for classically stable Type IIA de Sitter vacua typically starts with an ansatz that gives Anti-de Sitter supersymmetric vacua and then raises the cosmological constant by… Expand

Brane/antibrane dynamics and KKLT stability

- Physics
- 2015

String theory has few or no stable nonsupersymmetric or de Sitter vacua, only metastable ones. Antibranes are a simple source of supersymmetry breaking, as in the KKLT model, but various arguments… Expand

De Sitter vacua in string theory

- Physics
- 2003

We outline the construction of metastable de Sitter vacua of type IIB string theory. Our starting point is highly warped IIB compactifications with nontrivial NS and RR three-form fluxes. By… Expand

On classical de Sitter vacua in string theory

- Physics
- 2010

We review the prospect of obtaining tree-level de Sitter (dS) vacua and slow-roll inflation models in string compactifications. Restricting ourselves to the closed string sector and assuming the… Expand

Constraints on string cosmology

- Physics
- 2012

String theory contains sources like orientifold planes that support higher derivative interactions. These interactions make static flux compactifications possible which are forbidden in supergravity.… Expand

de Sitter string vacua from Kahler uplifting

- Physics
- 2007

We present a new way to construct de Sitter vacua in type IIB flux compactifications, in which the interplay of the leading perturbative and non-perturbative effects stabilize all moduli in dS vacua… Expand

Dark Energy in String Theory

- Physics
- 2015

We review the tension between the observational evidence for dark energy and various theoretical considerations. This tension has motivated a reconsideration of the issue of naturalness, and spawned… Expand

String cosmology and the landscape

- Physics
- 2017

Abstract String Theory is believed to have a landscape of 10500 vacua with properties that resemble those of our Universe. The existence of these vacua can be combined with anthropic reasoning to… Expand

De Sitter vacua from matter superpotentials

- Physics
- 2006

Consistent uplifting of AdS vacua in string theory often requires extra light degrees of freedom in addition to those of a (Kahler) modulus. Here we consider the possibility that de Sitter and… Expand