My post of July 22 « BICEP2 Data, CMB B-modes, Inflation, Alternative Cosmologies... (II) » already discussed the situation after the publication of the Physical Review Letters 112, 241101 version of the BICEP2 article « Detection of B-Mode Polarization at Degree Angular Scales by BICEP2 ». It clearly appears that the possible existence of primordial B-modes in the polarization of the cosmic microwave background (CMB) radiation would not by itself be an evidence for cosmic inflation, as alternative cosmologies can reproduce such an effect.
Simultaneously to the BICEP2 announcement, a theoretical work has been given media coverage : the paper « Higgs inflation at the critical point », by Fedor Bezrukov and Mikhail Shaposhnikov, arXiv:1403.6078, suggests that the Brout - Englert - Higgs field can lead cosmic inflation (Higgs inflation). The idea of identifying the Higgs boson with the inflaton was already suggested by the same authors in October 2007 (« The Standard Model Higgs boson as the inflaton
», arXiv:0710.3755)
But are there real evidences for cosmic inflation ?
COSMOLOGY, PARTICLE PHYSICS, INSTITUTIONS
There is a basic difference between Cosmology and Particle Physics at accelerators. Particle Physics experiments can in principle directly test all relevant theories in their energy domain. This has in particular been the case of the standard model, including the existence of the Brout - Englert - Higgs boson recently found at CERN. But it is impossible to reproduce the Big Bang in a laboratory. In spite of this obvious difference, there has been growing pressure in the recent period to impose a standard cosmological model. The quest for funding and jobs seems to have plaid a significant role in this evolution.
Cosmology is nowadays a very important field of scientific knowledge. Precisely for this reason, it should avoid dogmatism, scientific « party lines » and « mainstream » lobbying. Relevant missions and experiments should be financed without requiring that they immediately test the validity of an existing consensual theory. Data analyses should not be « oriented » by a priori theoretical prejudices, and institutional statements should be cautious.
Unfortunately, the institutional propaganda just after the March 17 announcement of the BICEP2 results (arXiv:1403.3985v1) was quite disappointing from this point of view. For instance :
- The Stanford University wrote (March 17) « New evidence from space supports Stanford physicist's theory of how universe began », and exhibited the video https://www.youtube.com/watch?feature=player_embedded&v=ZlfIVEy_YOA
- The Harvard University issued a March 17 statement entitled « First Direct Evidence of Cosmic Inflation »
- CALTECH wrote on March 17 « BICEP2 Discovers First Direct Evidence of Inflation and Primordial Gravitational Waves »
- In Europe, the April 30 CERN Courier published an article entitled « BICEP2 finds evidence of cosmic inflation »
Not such a strong statement was put forward without waiting for a scientific debate on the experimental and phenomenological side of the results announced by BICEP2, but the theoretical interpretation of a possible primordial B-mode signal in the polarization of the cosmic microwave background radiation was equally unilateral as pointed out in my notes :
« BICEP2, CMB B-modes And Spinorial Space-time »
« BICEP2, cosmic inflation, pre-Big Bang, SST, galactic effects... »
« BICEP2 Data, CMB B-modes, Inflation, Alternative Cosmologies... (I) »
« BICEP2 Data, CMB B-modes, Inflation, Alternative Cosmologies... (II) »
and in my two scientific articles reproduced in these posts.
What, then, about other claimed evidences for inflation ? Actually, all the analyses supporting inflation just ignore possible alternative cosmologies (pre-Big Bang, new ultimate constituents of matter, nexw space-time geometries...). But the SST approach naturally accounts for the observed flatness and, combined with superluminal ultimate constituents of matter (superbradyons), can also explain the homogeneity and isotropy of the observable Universe. The monopole problem can be avoided if new physics plays a significant role at the Grand Unification scale.
I started pointing out the potentialities of alternative cosmologies in my article Cosmological Implications of a Possible Class of Particles Able to Travel Faster than Light, Proceedings of the TAUP 1995 Conference, Nucl. Phys. Proc. Suppl. 48 (1996), 131, arXiv:astro-ph/9601090. My last paper on the subject, « CMB B-modes, spinorial space-time and Pre-Big Bang (II) », mp_arc 14-60, has been reproduced in the post « BICEP2 Data, CMB B-modes, Inflation, Alternative Cosmologies... (II) » .
