Negative cosmological constant from string theory

[Demystifier]

Allegedly, string theory (in it's simplest form) predicts that cosmological constant must be negative (or zero). Can someone explain where does this result come from? A reference would also be welcome.

 

[mitchell porter]

There is no such "result".

 

[Demystifier]

There is no such "result".

Not even in older literature? Then how to interpret the statement by Witten
"In fact, classical or not, I don’t know any clear-cut way to get de Sitter space from string theory or M-theory. This last statement is not very surprising given the classical no go theorem. For, in view of the usual problems in stabilizing moduli, it is hard to get de Sitter space in a reliable fashion at the quantum level given that it does not arise classically."
in http://lanl.arxiv.org/abs/hep-th/0106109 ?

 

[mitchell porter]

String theory in AdS is a modern topic.

 

[haushofer]

I'm not up to date to all the stringy constructions of backgrounds, but I think the problem you're addressing is deeper: it has to do with supersymmetry. E.g., pure N=1 D=4 supergravity can be constructed in a anti-deSitter background, but not a deSitter background. The reason is that the Jacobi identities of the underlying algebra don't allow for one particular sign of the cosmological constant (corresponding to dS).

 

[Demystifier]

I'm not up to date to all the stringy constructions of backgrounds, but I think the problem you're addressing is deeper: it has to do with supersymmetry. E.g., pure N=1 D=4 supergravity can be constructed in a anti-deSitter background, but not a deSitter background. The reason is that the Jacobi identities of the underlying algebra don't allow for one particular sign of the cosmological constant (corresponding to dS).

Thanks! Can you give a reference for that?

 

[Demystifier]

Maldacena and Nunez in http://lanl.arxiv.org/abs/hep-th/0007018
"we show that there are no non-singular Randall-Sundrum or de-Sitter compactifications for large class of gravity theories."

 

[mitchell porter]

Hey, you changed the question from "must be negative" to "must be negative (or zero)". For the record, my answer pertained to the original version.

 

[mitchell porter]

And you edited comment #3 to add the quote by Witten.

 

[haushofer]

Thanks! Can you give a reference for that?

See e.g. Freedman& Van Proeyen their sugra textbook, page 251 onward. My supervisor Eric Bergshoeff also published on construction of deSitter sugra on the arxiv, e.g.

https://arxiv.org/abs/1507.08264

but I haven't read it.