# String Propagation in the Presence of Cosmological Singularities

@article{Craps2002StringPI, title={String Propagation in the Presence of Cosmological Singularities}, author={Ben Craps and David Kutasov and Govindan Rajesh}, journal={Journal of High Energy Physics}, year={2002}, volume={2002}, pages={053-053} }

We study string propagation in a spacetime with positive cosmological constant, which includes a circle whose radius approaches a finite value as |t|??, and goes to zero at t = 0. Near this cosmological singularity, the spacetime looks like 1,1/. In string theory, this spacetime must be extended by including four additional regions, two of which are compact. The other two introduce new asymptotic regions, corresponding to early and late times, respectively. States of quantum fields in this…

## 116 Citations

String spectra near some null cosmological singularities

- Physics
- 2009

We construct cosmological spacetimes with null Kasner-like singularities as purely gravitational solutions with no other background fields turned on. These can be recast as anisotropic plane-wave…

Cosmological spacetimes from negative tension brane backgrounds

- Physics
- 2002

We identify a time-dependent class of metrics with potential applications to cosmology, which emerge from negative-tension branes. The cosmology is based on a gen- eral class of solutions to…

Comments on Cosmological Singularities in String Theory

- Physics
- 2002

We compute string scattering amplitudes in an orbifold of Minkowski space by a boost, and show how certain divergences in the four point function are associated with graviton exchange near the…

Exact string theory model of closed timelike curves and cosmological singularities

- Physics
- 2004

We study an exact model of string theory propagating in a space-time containing regions with closed timelike curves (CTCs) separated from a finite cosmological region bounded by a big bang and a big…

Null cosmological singularities and free strings: II

- Physics
- 2011

In arXiv:0909:4731, we argued that the free string lightcone Schrodinger wavefunctional in the vicinity of null Kasner-like cosmological singularities has nonsingular time-dependence if the Kasner…

Strings in an electric field, and the Milne Universe

- Physics
- 2003

Arguably the simplest model of a cosmological singularity in string theory, the Lorentzian orbifold 1,1/boost is known to lead to severe divergences in scattering amplitudes of untwisted states,…

Stringy Resolutions of Null Singularities

- Physics
- 2003

We study string theory in supersymmetric time-dependent backgrounds. In the framework of general relativity, supersymmetry for spacetimes without flux implies the existence of a covariantly constant…

Mirage resolution of cosmological singularities

- Physics
- 2004

We study time-dependent backgrounds in the low energy regimes of string theories. In particular the emphasis is on the general study of exotic phenomena such as positive acceleration and…

Unitarity in the presence of closed timelike curves

- Physics
- 2006

We conjecture that, in certain cases, quantum dynamics is consistent in the presence of closed timelike curves. We consider time dependent orbifolds of three-dimensional Minkowski space describing,…

Solvable model of strings in a time-dependent plane-wave background

- Physics, Mathematics
- 2003

We investigate a string model defined by a special plane-wave metric ds2 = 2du dv ? ?(u)x2 du2 + dx2 with ? = k/u2 and k = const > 0. This metric is a Penrose limit of some cosmological, Dp-brane and…

## References

SHOWING 1-10 OF 70 REFERENCES

A space-time orbifold: A toy model for a cosmological singularity

- Physics, Mathematics
- 2003

We explore bosonic strings and Type II superstrings in the simplest time dependent backgrounds, namely orbifolds of Minkowski space by time reversal and some spatial reflections. We show that there…

A New cosmological scenario in string theory

- Physics
- 2002

We consider new cosmological solutions with a collapsing, an intermediate and an expanding phase. The boundary between the expanding (collapsing) phase and the intermediate phase is seen by comoving…

M-theory observables for cosmological space-times

- Physics, Mathematics
- 2001

We discuss the construction of the analog of an S-matrix for space-times that begin with a Big-Bang and asymptote to an FRW universe with nonnegative cosmological constant. When the cosmological…

Global analysis of new gravitational singularities in string and particle theories.

- MathematicsPhysical review. D, Particles and fields
- 1992

A global analysis of the geometries that arise in noncompact current algebra (or gauged WZW) coset models of strings and particles propagating in curved space-time and discusses the geodesically complete spaces on each side of these surfaces and interpret the motion of particles in physical terms.

From big bang to big crunch and beyond

- Physics
- 2002

We study a quotient Conformal Field Theory, which describes a 3+1 dimensional cosmological spacetime. Part of this spacetime is the Nappi-Witten (NW) universe, which starts at a ``big bang''…

Clean Time-Dependent String Backgrounds from Bubble Baths

- Physics
- 2002

We consider the set of controlled time-dependent backgrounds of general relativity and string theory describing `bubbles of nothing', obtained via double analytic continuation of black hole…