Big bang nucleosynthesis, the CMB, and the origin of matter and space-time

Abstract

We summarize some applications of big bang nucleosythesis (BBN) and the cosmic microwave background (CMB) to constrain the first moments of the creation of matter in the universe. We review the basic elements of BBN and how it constraints physics of the radiation-dominated epoch. In particular, how the existence of higher dimensions impacts the cosmic expansion through the projection of curvature from the higher dimension in the "dark radiation" term. We summarize current constraints from BBN and the CMB on this brane-world dark radiation term. At the same time, the existence of extra dimensions during the earlier inflation impacts the tensor to scalar ratio and the running spectral index as measured in the CMB. We summarize how the constraints on inflation shift when embedded in higher dimensions. Finally, one expects that the universe was born out of a complicated multiverse landscape near the Planck time. In these moments the energy scale of superstrings was obtainable during the early moments of chaotic inflation. We summarize the quest for cosmological evidence of the birth of space-time out of the string theory landscape. We will explore the possibility that a superstring excitations may have made itself known via a coupling to the field of inflation. This may have left an imprint of "dips" in the power spectrum of temperature fluctuations in the cosmic microwave background. The identification of this particle as a superstring is possible because there may be evidence for different oscillator states of the same superstring that appear on different scales on the sky. It will be shown that from this imprint one can deduce the mass, number of oscillations, and coupling constant for the superstring. Although the evidence is marginal, this may constitute the first observation of a superstring in Nature.

Evidence for Planck-scale resonant particle production during inflation from the CMB power spectrum

“…A number of mechanisms have been proposed (see summary in Ref. [1]) to deal with the suppression of the power spectrum on large scales and low multipoles. Most of these works, however, were concerned with the suppression of the lowest moments via changes in the inflation generating potential.…”

Explaining low l anomalies in the CMB power spectrum with resonant superstring excitations during inflation

“…There have been a number of papers exploring the possible impact of string theory on the cosmic microwave background [2]- [10]. This paper explores the possibility that a specific sequence of super-string excitations may have made a e-mail: mayukh.raj@saha.ac.in b e-mail: gmathews@nd.edu c e-mail: ichiki.kiyotomo@c.mbox.nagoya-u.ac.jp d e-mail: kajino@nao.ac.jp itself known via its coupling to the inflaton field of inflation.…”

“…This paper explores the possibility that a specific sequence of super-string excitations may have made a e-mail: mayukh.raj@saha.ac.in b e-mail: gmathews@nd.edu c e-mail: ichiki.kiyotomo@c.mbox.nagoya-u.ac.jp d e-mail: kajino@nao.ac.jp itself known via its coupling to the inflaton field of inflation. This may have left an imprint of "dips" [10] in the T T and EE power spectra of the cosmic microwave background. The identification of this particle as a superstring is possible because there may be evidence for sequential oscillator states of the same superstring that appear on different scales of the sky.…”

“…Nevertheless, a number of mechanisms have been proposed [17] to deal with the possible suppression of the power spectrum on large scales and low multipoles. In addition to being an artifact of cosmic variance [15,18], large-scale power suppression could arise from changes in the effective inflation-generating potential [19], differing initial conditions at the beginning of inflation [10,20,21,[24][25][26][27][28][29], the ISW effect [30], effects of spatial curvature [31], non-trivial topology [32], geometry [33,34], a violation of statistical anisotropies [35], effects of a cosmological-constant type of dark energy during inflation [36], the bounce due to a contracting phase to inflation [37,38], the production of primordial micro black-holes [39], hemispherical anisotropy and non-gaussianity [40,41], the scattering of the inflationary trajectory in multiple field inflation by a hidden feature in the isocurvature direction [42], brane symmetry breaking in string theory [43,44], quantum entanglement in the M-theory landscape [45], or loop quantum cosmology [46], etc.…”

“…In a previous work [10], we considered another possibility, i.e. that the suppression of the power spectrum in the range = 10 − 30 in particular could be due to the resonant creation [48,49] of Planck-scale fermions that couple to the inflaton field.…”