Constraints on the fundamental string coupling

Transcription

1 Constraints on the fundamental string coupling from future CMB B-mode experiments Levon Pogosian (SFU) Tasos Avgoustidis (DAMTP), Ed Copeland (Nottingham), Adam Moss (UBC), LP, Alkistis Pourtsidou (Manchester), Dani Steer (APC), arxiv: ; arxiv:

2 CMB polarization DASI 2002

3 E (gradient) and B (curl) modes from M. Zaldarriaga, astro-ph/

4 Sources of parity odd (B) mode Lensing of fe-mode by large scale structures t (scalar modes, 2nd order in PT) Primordial gravity waves, e.g. from inflation (tensor modes) Magnetic fields Anisotropic stress produced by cosmic defects, e.g. cosmic strings (vector and tensor modes)

5 B-mode spectrum from strings recombination peak reionization peak LP and M. Wyman, arxiv:

6 Why cosmic strings? Topological defects are fun Beyond simplest inflation o multi-field inflation models Superstrings can be cosmic o brane inflation i o string theory in the sky Jones, Stoica and Tye, JHEP 07 (2002) 051 Sarangi and Tye, PLB 536 (2002) 185 Kachru, Kallosh, Linde, Maldacena, McAllister and Triverdi, JCAP 0310 (2003) 013 Dvali and Vilenkin, JCAP 0403 (2004) 010 Copeland, Myers and Polchinski, JHEP 06 (2004) 013.

7 Strings can source up to 5-10% of CMB TT power (f s =0.1) Even at 0.1% (f s =0.001) 001) they can source observable B-modes J. Urrestilla, N. Bevis, M. Hindmarsh, M. Kunz, arxiv: J U es a, e s, d a s, u, a R. Battye, A. Moss, arxiv:

8 Planck, SPIDER, EBEX, PolarBear, QUIET, C0rE Avgoustidis et al,

9 Can we go beyond detection? String Theory in the sky?

10 Multi-Tension (FD) String Networks many types of strings (F, D, FD, ) different intercommuting probabilities junction formation

11 Ingredients for scaling Expansion of the universe increases the length of the infinite strings without stretching them When strings intersect, they can reconnect and chop off loops

12 The One-Scale Model expansion Formation of loops Kibble, 1985 Loop chopping efficiency Velocity-dependent one-scale model Velocity-dependent one-scale model Martins & Shellard, 1996, 2002

13 Scaling solution in VOS

14 A Multi-Tension String Network Model depend depend on P ij and junction kinematics on P ii Energy conservation at junctions Avgoustidis & Copeland, 2010

15 Dependence on the fundamental coupling g s J k J P l hi ki 2005 Jackson, Jones, Polchinski, 2005 Hannany & Hashimoto, 2005 Pourtsidou et al, 2011

16 Light and populous vs heavy and rare The lightest (F) strings are always the most populous Light, populous p F strings dominate the power spectrum at large couplings Heavy, rare D strings dominate the power spectrum at small couplings

17 The peak of B-mode spectrum at different string couplings

18 Planck, SPIDER, EBEX, PolarBear, QUIET, C0rE S/N in detecting the difference between large and small g s S/N of overall detection Avgoustidis et al,

19 Combining CMB and GW probes CMB and GW constrain different combinations of string tension and string number density Battye and Moss, 2010 This can partially break the degeneracy between fundamental tension and coupling

20 Avgoustidis et al, Combining CMB and GW probes

21 Summary Strings are currently allowed to produce up to 5-10% of CMB temperature anisotropy. Even at 0.1%, they can source observable B-modes Light, populous F strings dominate the power spectrum at large couplings. Heavy rare D strings dominate at small couplings Measurements of the B-mode spectrum can differentiate between the limiting cases of large and small couplings C bi i diff t b ti ll b k th d Combining different probes partially breaks the degeneracy between heavy rare and light populous strings