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    BICEP2, CMB B-modes And Spinorial Space-time
    By Luis Gonzalez-Mes... | March 26th 2014 06:30 AM | 6 comments | Print | E-mail | Track Comments
    About Luis

    Staff researcher at CNRS (France) in 1972-2013. Now leading the Cosmology Laboratory of the Megatrend University (Belgrade and Paris). For my work...

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    Would the existence of B-modes in the cosmic microwave background (CMB) radiation be an evidence for inflation? Many influential colleagues claim that this is indeed the case. But their arguments are based on standard cosmological schemes.

    Actually, pre-Big Bang patterns beyond conventional cosmology do not require inflation and can generate CMB B-modes.

    Two papers by the BICEP2 Collaboration :

    BICEP2 I: Detection Of B-mode Polarization at Degree Angular Scales, arXiv:1403.3985
    BICEP2 II: Experiment and Three-Year Data Set, arXiv:1403.4302

    announced the possible finding of a B-mode polarization signature of the cosmic microwave background. This was immediately interpreted, assuming it would be confirmed, as an observational proof of cosmic inflation through gravitational wave effects. The claim being that a gravitational potential can only generate E-modes (basically, a gradient) whereas gravitational waves can also generate (rotational) B-modes.

    However, this argument does no longer hold if a privileged space direction exists for each point of space-time, as automatically generated by the spinorial space-time (SST) I introduced in 1996-97 (see my previous articles in this blog) and possibly found by the Planck collaboration :

    Planck 2013 results. XXIII. Isotropy and statistics of the CMB, arXiv:1303.5083

    In the SST pattern, the privileged space direction is an intrinsic property of space-time and was already present in the very early Universe. Then, a simple rotation around the privileged space direction generates a B-mode and the vector product of any E-like vector by this direction naturally leads to a B-like pseudovector. Such a scenario appears much less ad hoc than inflation.

    The spinorial space-time describes and automatically expanding universe where the spinor modulus corresponds to the cosmic time (age of the Universe). Standard matter is then generated in an already expanding space, and can dynamically react (in particular, through gravitation) to this pre-existing expansion of purely geometric origin. This can be at the origin of a nonstandard contribution of gravitation to the generation of CMB B-modes.

    See also my recent papers on the subject :

    Pre-Big Bang, fundamental Physics and noncyclic cosmologies, http://hal.archives-ouvertes.fr/hal-00795588
    Planck data, spinorial space-time and asymptotic Universe, https://archive.org/details/PlanckSST
    Spinorial space-time and privileged space direction (I), https://archive.org/details/PrivSpDir
    Spinorial space-time and Friedmann-like equations (I), https://archive.org/details/SSTFriedmannbis

    My two contributions to the ICNFP 2013 Proceedings will also be soon available.

    Luis Gonzalez-Mestres


    Luis Gonzalez-Mestres
    Concerning the possible role of gravitation, in the conclusion of my April 2013 paper Planck data, spinorial space-time and asymptotic Universe, https://archive.org/details/PlanckSST I wrote :


    As the leading contribution to the Universe expansion comes from this (S3) curvature term generated in the spinorial space-time previous to the introduction of standard matter and outside the standard general-relativistic framework, standard matter can react to this geometric constraint. Such an interaction between matter and geometry would lead to a new terms in the modified Friedmann-like equations. If the reaction of standard matter has initially slowered the Universe expansion when the matter density was much larger, the apparent cosmic acceleration can be just an evolution associated to the weakening of matter density and restoring asymptotically the expansion rate from fundamental geometry.

    Thus, it is tempting to conjecture that, contrary to many claims, the observed acceleration of the expansion of the Universe is just the reflect of a fluctuation due to gravitation, and perhaps to other standard interactions, in the presence of the pre-existing spinorial space-time geometry. As the Universe expands, the product H t tends to 1 (except possibly for a small correction to this value) as the natural asymptotic limit at t → ∞ . Data from Planck and other experiments appear compatible with such a hypothesis that does not appear naturally in the CDM model.

    Similarly, as the spinorial space-time has been previous to the formation of conventional matter, it seems reasonable to assume that its expansion is in equilibrium with a primordial vacuum possibly
    formed during a short pre-Big Bang era.


    (end of quote, H is the Lundmark-Lemaître-Hubble constant and t the cosmic time)

    But unconventional dynamics can also have been at work in the generation of the origin of CMB B-modes in pre-Big Bang scenarios.
    Luis Gonzalez-Mestres
    The existence of a privileged space direction for each comoving observer in the spinorial space-time, where the cosmic time is given by the modulus of the cosmic spinor associated to each point of space-time (or by a function of this modulus such as its square), originates from the fact that the standard space rotation group SO(3) is replaced by its covering group SU(2).

    Then, to each space point at a given value of the cosmic time t it is possible to associate a space trajectory defined by the set of SU(2) transformations that leave the cosmic spinor invariant up to a complex phase. These transformations form a one-dimensional subgroup of SU(2) and define locally a privileged space direction.

    See, in this blog :

    A Privileged Space Direction? Spinorial Space-time, WMAP, Planck (I)
    A Privileged Space Direction? Spinorial Space-time, WMAP, Planck (II)
    Dark matter and dark energy, or Pre-Big Bang geometry?

    Luis Gonzalez-Mestres
    Luis Gonzalez-Mestres
    More generally, any cosmology incorporating or generating a privileged space direction for each comoving observer can naturally produce CMB B-modes without inflation.
    The idea they may have underestimated the galactic foreground emission continues to grow.
    Luis Gonzalez-Mestres
    Some of the authors of the BICEP2 papers :


    are also members of the Planck collaboration :


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