Strings in Time-Dependent Orbifolds

By Hong Liu, G. Moore, N. Seiberg. 2002

213 citations recorded by the source corpus.

We continue and extend our earlier investigation ``Strings in a Time-Dependent Orbifold'' (hep-th/0204168). We formulate conditions for an orbifold to be amenable to perturbative string analysis and classify the low dimensional orbifolds satisfying these conditions. We analyze the tree and torus amplitudes of some of these orbifolds. The tree amplitudes exhibit a new kind of infrared divergences which are a result of some ultraviolet effects. These UV enhanced IR divergences can be interpreted as due to back reaction of the geometry. We argue that for this reason the three dimensional parabolic orbifold is not amenable to perturbation theory. Similarly, the smooth four dimensional null-brane tensored with sufficiently few noncompact dimensions also appears problematic. However, when the number of noncompact dimensions is sufficiently large perturbation theory in these time dependent backgrounds seems consistent.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics, Statistical and Nonlinear Physics

View Paper: https://www.semanticscholar.org/paper/c65907edf8e6bc88ef4e1356e0cbd07c8708a655

How researchers see this paper

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In Astronomy and Astrophysics

1. A. Adams
2. John McGreevy
3. K. Balasubramanian
4. E. Silverstein
5. Ben Craps
6. M. Berkooz
7. G. Rajesh
8. T. Takayanagi

In Nuclear and High Energy Physics

1. K. Balasubramanian
2. John McGreevy
3. A. Adams
4. E. Silverstein
5. T. Takayanagi
6. S. Hartnoll
7. S. Sethi
8. Ben Craps

In Statistical and Nonlinear Physics

1. Ben Craps
2. M. Berkooz
3. G. Rajesh
4. D. Kutasov
5. A. Adams
6. John McGreevy
7. E. Silverstein
8. Erik P. Verlinde

Citations in the corpus

• A matrix big bang (2005, background): “Although there is now no gravitational backreaction, one can show along the lines of [6] that large gauge backreaction gives rise to UV enhanced IR divergences similar to the ones found in [3].”
• Hot spacetimes for cold atoms (2008, background): “thus a natural IR regulator. Finally, and most sharply, even in the strict T → 0 case, the dynamics will resolve this “singularity” in a fashion familiar from the study of null orbifolds of flat space [30, 31, 32, 33]: a pulse of stress-energy sent towards large ris steadily blue-shifted until its ba”
• Time‐dependent orbifolds and string cosmology (2003, unknown): “For the null–brane [16, 63], where the orbifold generator includes a translation P3 along an extra spatial direction, a similar focusing occurs, at X = −J2+/p+.”
• Comments on Cosmological Singularities in String Theory (2002, background): “The classical backreaction in a class of models which can be described near the singularity by certain Lorentzian orbifolds has recently been studied in [7,12,15].”
• The tachyon at the end of the universe (2005, background): “Relatedly, black hole formation of the sort found in [25,26] is evaded here: the tachyon lifts the degrees of freedom of the system before the Planckian regime is reached.”
• Ekpyrotic and cyclic cosmology (2008, background): “It is also known that perturbative string theory breaks down in these and similar settings as soon as interactions are taken into account [71,13,27].”
• Instability of spacelike and null orbifold singularities (2002, unknown): “[13, 14] extend the analysis of LMS to the nonsingular orbifold in which the null boost is accompanied by a spacelike shift, and include remarks about the backreaction that overlap with ours.”