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Nonlocal Dynamics in String Field Theory and cosmological applications

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Liudmila Joukovskaya,

CTC, DAMTP, University of Cambridge

21 January, Imperial College London

- General Motivations
- Construction of rolling solutions in the truncated SFT
a) Truncated SFT (nonlocality)

b) Space homogeneous rolling solutions

- Cosmological motivations for nonlocal theories
- SFT as a possible framework for cosmology
- Rolling cosmological solutions

- Cosmological Motivations
- Theoretical Motivations
- String Field Theory as a possible framework for Cosmology

Witten’s Cubic Open String Field Theory

E. Witten, Nucl. Phys. B 268 (1986) 253

V.A. Kostelecky, S.Samuel,

Phys. Lett. B 207 (1988) 169

V.A. Kostelecky,S.Samuel, Phys. Lett. B 207 (1988) 169,

P.West, Phys.Lett.B548:92-96,2002

N. Moeller, A. Sen, B. Zwiebach, JHEP, 08 (2000) 039

Cubic Fermionic String Field Theory

I.Aref’eva, P.Medvedev, A.Zubarev

Phys.Lett.B240 (1990)356

C.Preitschopf, C.Thorn, S.Yost,

Nucl. Phys. B337 (1990) 363

I.Arefeva, D.Belov, A.Koshelev,

P.Medvedev, Nucl.Phys.B638 (2002)3

In the approximation u=U we have a more simple approximate action

Level truncation

Covariant String Field Theory

Spatially-Homogeneous Configurations

N. Moeller, B. Zwiebach, JHEP, 10 (2002) 034

H. Yang, JHEP 11 (2002) 007

I. Aref’eva, L.J., A. Koshelev, JHEP, 09 (2003) 012

Ya. Volovich, JPA, 2003; Ya. Volovich, V.S. Vladimirov, Theor. Math. Phys. 2004;

L.J., Theor. Math. Phys. 2006 or arxiv: 0708.0642[hep-th];

V.S. Vladimirov, arxiv: 0705.4600

D. V. Prokhorenko, math-ph/0611068; G. Calcagni, G. Nardelli, arxiv: 0708.0366

Solution of Equation of Motion

Standard Cosmological Concordance Model is emerging

during the last 10 years …

Picture taken from:cosmology.berkeley.edu

N. Turok, P.J. Steinhardt,

J. Khoury, B. Ovrut

A great discovery of the last few years is the discoveryof the current accelerated expansion of the Universe

Observations (1998) of very distant supernovae demonstrated that the Universe is expanding with an acceleration. Ia Supernovae: S.Perlmutter et al., A.Riess et al., 1998;

This acceleration seems to be explicable by the presence of a new component of matter called dark energy (DE).

DE is a special unknown form of matter with negative pressure and it provides universal repulsive forces (antigravity).

Picture taken from: http:// map.gsfc.nasa.gov

One more reason to work on new inflationary candidates

Standard Cosmological Concordance Model is emerging

during the last 10 years…

String Field Theory as a possible cosmological framework

- Non-local gravity ad-hoc:

Arkani-Hamed at al hep-th/0209227;

Khoury, hep-th/0612052;

T.Biswas, A.Mazumdar, W.Siegel, hep-th/0508194,

G.Dvali, S. Hofmann, JKhoury,hep-th/0703027

S.Deser, R.Woodard, arXiv:0706.2151S.

- Non-local SFT:

I.Aref’eva, LJ, A.Koshelev, JHEP, 2003;

I.Aref’eva, LJ, JHEP, 2005

G.Calcagni, JHEP, 2005

LJ, PRD 2007

G. Calcagni, M.Montobbio, G.Nardelli; PRD 2007

N. Barnaby, T. Biswas, J.M. Cline, JHEP 2007

J.Lidsey, PRD 2007;

D. Mulryne, N. Nunes, PRD 2008

Einstein equations

FriedmannCosmology

+ Cosmological principle

Isotropic

Homogeneous

K=+1 (3-sphere), k=0 (plane), k=-1 (3-hyperboloid)

L.J., PRD 2007

Two fields case

L.J., arxiv: 0807.2065

a.

b.

a.

b.

- Construction of rolling cosmological solutions for:

- Tachyon field describing non-BPS branes
in Friedmann-Robertson-Walker background

(Does exist in Minkowski case AJK)

- Tachyon field of open bosonic string
in Friedmann-Robertson-Walker background

(Does not exist in the Minkowski case (Moeller, Zwiebach) )

Conclusions and further directions

Thank you for the attention!