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PPPDT Feb 27: ‘unofficial’ response to questions. Lawrence Krauss CWRU. Positive B-modes?. Something happening close to GUT scale! If inflation: points to perturbative power series single field potentials (dominated by m^2 phi^2 term) with large values of phi.
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PPPDT Feb 27: ‘unofficial’ response to questions Lawrence Krauss CWRU
Positive B-modes? • Something happening close to GUT scale! • If inflation: points to perturbative power series single field potentials (dominated by m^2 phi^2 term) with large values of phi. • BUT: NOT AN UNAMBIGUOUS SIGNAL OF INFLATION. (KJS,LMK,HM (PRL, in press))
EX: O(N) Phase Transition • Causality implies GW spectrum generated on the horizon at all times (LMK, ‘92) • Exact calculation much bigger than naïve estimate:
Small r? • Important constraint: validates smaller than M_pl field variation. • Note: expectation value of r depends upon priors. (LMK, WV ‘08, prelim)
Conclusions • Whether r is small or large, we learn a great deal.. I do not believe we are likely to be able to unambiguously infer the existence or nature of inflation.. But a B-mode mission will directly probe the GUT scale and quantitative physics in a way that Dark Energy mission is not likely to, for example.
