de Sitter Vacua in the String Landscape:
La Petite Version
Keshav Dasgupta, Maxim Emelin, Mir Mehedi Faruk, and Radu Tatar
Abstract In this review we argue that four-dimensional effective field theory
descriptions with de Sitter isometries are allowed in the presence of time-dependent
internal degrees of freedom in type IIB string landscape. Both moduli stabilizations
and time-independent Newton constants are possible in such backgrounds. However
once the time-dependences are switched off, there appear no possibilities of
effective field theory descriptions and these backgrounds are in the swampland.
Keywords String theory · M-theory · de Sitter vacua · Flux compactifications
1 Introduction
The late time (quasi-)de Sitter vacuum is a desired consequence of any UV
complete theory of quantum gravity, therefore one would expect its appearance
in string theory. Earlier attempts to reproduce such a vacuum in the context of
type II theories [1] have had some successes although more recently various
questions have been raised (see, for example, [2–4]) regarding the validity of such
computations. The answers to some of these objections are attempted in [5] and
[6], mostly by clarifying the role of anti D3-branes as one of the key ingredients
in realizing a four-dimensional de Sitter vacuum. A more serious objection, not
just against the computations of [1], but against the very existence of de Sitter
vacua in the string landscape, has been recently raised in [7] claiming that string
theory prefers quintessence instead of an inflationary evolution towards a late time
de Sitter vacuum. The situation is rather paradoxical because objections against
models of quintessence were around from early on, and more recently [8] showed
K. Dasgupta () · M. Emelin · M. M. Faruk
Department of Physics, McGill University, Montreal, QC, Canada
e-mail: keshav@hep.physics.mcgill.ca; maxim.emelin; mir-faruk@mail.mcgill.ca
R. Tatar
Department of Mathematics, University of Liverpool, Liverpool, UK
e-mail: Radu.Tatar@Liverpool.ac.uk
© Springer Nature Switzerland AG 2021
M. B. Paranjape et al. (eds.), Quantum Theory and Symmetries, CRM Series in
Mathematical Physics, https://doi.org/10.1007/978-3-030-55777-5_41
447
La Petite Version
Keshav Dasgupta, Maxim Emelin, Mir Mehedi Faruk, and Radu Tatar
Abstract In this review we argue that four-dimensional effective field theory
descriptions with de Sitter isometries are allowed in the presence of time-dependent
internal degrees of freedom in type IIB string landscape. Both moduli stabilizations
and time-independent Newton constants are possible in such backgrounds. However
once the time-dependences are switched off, there appear no possibilities of
effective field theory descriptions and these backgrounds are in the swampland.
Keywords String theory · M-theory · de Sitter vacua · Flux compactifications
1 Introduction
The late time (quasi-)de Sitter vacuum is a desired consequence of any UV
complete theory of quantum gravity, therefore one would expect its appearance
in string theory. Earlier attempts to reproduce such a vacuum in the context of
type II theories [1] have had some successes although more recently various
questions have been raised (see, for example, [2–4]) regarding the validity of such
computations. The answers to some of these objections are attempted in [5] and
[6], mostly by clarifying the role of anti D3-branes as one of the key ingredients
in realizing a four-dimensional de Sitter vacuum. A more serious objection, not
just against the computations of [1], but against the very existence of de Sitter
vacua in the string landscape, has been recently raised in [7] claiming that string
theory prefers quintessence instead of an inflationary evolution towards a late time
de Sitter vacuum. The situation is rather paradoxical because objections against
models of quintessence were around from early on, and more recently [8] showed
K. Dasgupta () · M. Emelin · M. M. Faruk
Department of Physics, McGill University, Montreal, QC, Canada
e-mail: keshav@hep.physics.mcgill.ca; maxim.emelin; mir-faruk@mail.mcgill.ca
R. Tatar
Department of Mathematics, University of Liverpool, Liverpool, UK
e-mail: Radu.Tatar@Liverpool.ac.uk
© Springer Nature Switzerland AG 2021
M. B. Paranjape et al. (eds.), Quantum Theory and Symmetries, CRM Series in
Mathematical Physics, https://doi.org/10.1007/978-3-030-55777-5_41
447