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Deformation, non-commutativity and cosmological constant problem. Renata Kallosh. Stanford. Davis, May 16, 2004. Outline. 1. Observational data on DARK ENERGY and INFLATION  CC PROBLEM 2. String Theory- Cosmology: KKLT model of de Sitter space,

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deformation non commutativity and cosmological constant problem

Deformation, non-commutativity and cosmological constant problem



Davis, May 16, 2004


1. Observational data on DARK ENERGY and INFLATION  CC PROBLEM

2.String Theory- Cosmology: KKLT model of de Sitter space,

Warping  small parameter from deformed conifold.

Problems with warping in KKLMMT model of inflation

3. Hybrid Inflation/Acceleration in D3/D7 Brane System

4. Deformed non-linear instanton, Nekrasov-Schwarz non-commutative instanton

5. Irrational deformation (non-commutativity) parameter

in 6,7,8,9 space  CC in 0,1,2,3 space.


Replace D0/D4

by D3/D7


in the space orthogonal to D3


Constant in

effective 4d

cmbgg omol2

How much dark energy is there?

Cmbgg OmOl







WMAP + SDSS: lots

cmbgg omol4

How much dark energy is there?

Cmbgg OmOl







Tegmark et al, 2004

cosmological concordance model
Early Universe Inflation

Near de Sitter space

13.7 billion years ago

During 10^{-35} sec

Current Acceleration

Near de Sitter space


During few billion years

Cosmological Concordance Model
dark energy
  • Total energy in 3d flat FRW universe


  • 70% of the total energy of the universe is DARK
c osmological c onstant cc problem
Cosmological Constant (CC) Problem
  • The simplest form of dark energy: CC
string theory and cosmology
String Theory and Cosmology
  • All observations fit 4d Einstein GR: how to get this picture from the compactified fundamental 10d string theory or 11d M-theory and supergravity

How to get de Sitter or near de Sitter 4d space?


Towards cosmology in type IIB string theory

Dilaton stabilization Giddings, Kachru and Polchinski 2001

Volume stabilization, KKLT

Kachru, R. K, Linde, Trivedi 2003

Landscape Susskind Flux Vacua Douglas

Kachru, R. K., Maldacena, McAllister, Linde and Trivedi 2003


Deformed Conifold

Copeland, Myers,

Polchinski picture

The throat geometry has a highly warped region

volume stabilization
Volume stabilization
  • Warped geometry of the compactified space and nonperturbative effects allows to obtain AdS space with unbroken SUSY and stabilized volume
  • One can uplift AdS space to a metastable dS space by adding anti-D3 brane at the tip of the conifold
the role of warping factor in uplifting ads vacuum to ds
The role of warping factor inuplifting AdS vacuum to dS
  • Small z (resolution of conifold singularity)

In our example C was 10-9

Small C is necessary for dialing the anti-D3 energy to AdS scale to preserve and uplift the minimum

the redshift in the throat plays the key role in
The redshift in the throat plays the key role in
  • Advantage: source of small parameters
  • Disadvantage: highly warped region of KS geometry corresponds to conformal coupling of the inflaton field (position of D3-brane in the throat region)

Flatness of the Inflaton Potential and of the

Perturbation Spectrum Require

Few possibilities to improve the model are known

supersymmetry and inflation
Supersymmetry and Inflation

Linde, 91

  • Hybrid Inflation

F-term, D-term Inflation

Copeland, Liddle, Lyth, Stewart, Wands;

Dvali, Shafi, Shafer, 94

Binetruy, Dvali; Halyo, 96; Dvali, Tye, 99

D3/D7 Brane Inflation as D-term Inflation

Dasgupta, Herdeiro, Hirano, R.K., 2002

Burgess, Kallosh, Quevedo, 2003

Include Volume Stabilization:

F-term for KKLT+ Shift Symmetry

slightly broken by quantum corrections

Hsu, R. K., Prokushkin, 2003-2004

Ferrara et al, 2003

Practically D-term Inflation

inflaton trench
Inflaton Trench

Supersymmetric Ground State of Branes in Stabilized Volume


The motion of branes does not destabilize the volume

cosmology supersymmetry and special geometry
Cosmology, Supersymmetry and Special Geometry
  • In familiar case of Near Extremal Black Holes

DUALITY SYMMETRY protects exact entropy formula from large quantum corrections

DUALITY SYMMETRY (shift symmetry)

protects the flatness of the potential

in D3/D7 inflation model from large quantum corrections

the potential of the hybrid d3 d7 inflation model
The Potential of the Hybrid D3/D7 Inflation Model

is a hypermultiplet

is an FI triplet: resolution of the singularity

same potential without fayet iliopoulos term
Same Potential without Fayet-Iliopoulos term

Flat direction corresponding to the singularity

in the moduli space of instantons in D3/D7

d3 d7 brane inflation model

The mass of D3-D7 strings (hypers) is split due to the presence of the deformed flux on D7

de sitter stage waterfall ground state
De Sitter stage- Waterfall- Ground State

DeSitter: Inflation or current acceleration

Ground state: D3/D7 bound state

Higgs branch: non-commutative instantons

NS non-commutative instantons:

Higgs branch, bound state of D0/D4

D3 can move away from D7 when the deformationparameter vanishes, the moduli space is singular: there isno de Sitter space

Resolution of singularity of the moduli space of

instantons in D3/D7 Higgs branch

requires that the Coulomb branch has a non-vanishing D-term potential

Deformation-non-commutativity-resolution of singularity

de Sitter space

dbi kappa symmetric action and non linear deformed instantons
DBI kappa-symmetric action and non-linear deformed instantons

Seiberg,Witten, 99; Marino, Minassian, Moore, Strominger, 99

D3/D7 bound state and unbroken supersymmetry

Bergshoeff, R. K., Ortin, Papadopoulos, 97

Deformed flux on the world-volume

Non-linear deformed instanton

d term volume stabilization
D-term volume stabilization

Instead of anti-D3 add D7 with flux. The D-term potential depends on the ASD deformed flux and volume modulus

2 possibilities to make this mechanism working

1) Place D7 in highly warped region of space

Burgess, R. K., Quevedo

2) Use deformation: irrational


cannot be gauged away into

Deformation parameter (non-commutativity)

is not quantized, it can be small!


In the context of non-commutative instantons (Nekrasov-Schwarz, 1998) and Dirac-Born-Infeld non-linear instantons (Seiberg-Witten, 1999) FI terms are necessary to make the Abelian instantons non-singular.

It is tempting to speculate that in D3/D7 cosmological model with volume stabilization mechanism there is an explanation of the non-vanishing effective cosmological constant

Non-commutativity parameter (FI term in effective theory) is needed to remove the instanton moduli space singularity in the description of the supersymmetric D3/D7 bound state when D3 has dissolved into D7.

The same cosmological model must have a non-supersymmetric de Sitter stage when D3 is separated from D7


Can we measure the

non-commutativity parameters of the internal space

by looking at the sky ?

Hopefully, with the further development of the theory we will find an answer to this question