Comment on "CCC-predicted low-variance circles in CMB sky and LCDM"

TL;DR

This paper critically examines claims of low-variance circles in the CMB sky by Gurzadyan and Penrose, demonstrating that their simulations used an inappropriate power spectrum, thus invalidating their findings.

Contribution

The paper provides a detailed critique of Gurzadyan and Penrose's methodology, emphasizing the importance of using the correct power spectrum in CMB simulations.

Findings

Gurzadyan and Penrose's claims are based on incorrect power spectrum assumptions.

Independent reanalyses used the proper LCDM spectrum and did not find the claimed circles.

The paper highlights issues in scientific sociology and peer review processes.

Abstract

In a recent preprint ("CCC-predicted low-variance circles in the CMB sky and LCDM"), Gurzadyan and Penrose (2011) claim for the second time to find evidence for pre-Big Bang activity in the form of concentric circles of low variance in the WMAP data. The same claim was made in November 2010, but quickly shown to be false by three independent groups. The culprit was simply that Gurzadyan and Penrose's simulations were based on an inappropriate power spectrum. In the most recent paper, they now claim that the significance is indeed low if the simulations are based on the realization-specific WMAP spectrum (ie., the one directly measured from the sky maps and affected by cosmic variance), but not if the simulations are based on a theoretical LCDM spectrum. In this respect, we note that the three independent reanalyses all based their simulations on the LCDM spectrum, not the observed WMAP spectrum, and this alone should suffice to show that the updated claims are also incorrect. In fact, it is evident from the plots shown in their new paper that the spectrum is still incorrect, although in a different way than in their first paper. Thus, Gurzadyan and Penrose's new claims are just as wrong as those made in the first paper, and for the same reason: The simulations are not based on an appropriate power spectrum. Still, while this story is of little physical interest, it may have some important implications in terms of scienctific sociology: Looking back at the background papers leading up to the present series by Gurzadyan and Penrose, in particular one introducing the Kolmogorov statistic, we believe one can find evidence that a community based and open access referee process may be more efficient at rejecting incorrect results and claims than a traditional journal based approach.