Can compactifications solve the cosmological constant problem?
Author(s)
Masoumi, Ali
Hertzberg, Mark Peter
Date Issued
June 2016
Journal
Journal of Cosmology and Astroparticle Physics
Publisher
Institute of Physics Publishing/SISSA
Citation
Hertzberg, Mark P., and Ali Masoumi. “Can Compactifications Solve the Cosmological Constant Problem?” Journal of Cosmology and Astroparticle Physics 2016.06 (2016): 053–053. © Copyright 2017 IOP Publishing
Version
Final published version
Abstract
Recently, there have been claims in the literature that the cosmological constant problem can be dynamically solved by specific compactifications of gravity from higher-dimensional toy models. These models have the novel feature that in the four-dimensional theory, the cosmological constant Λ is much smaller than the Planck density and in fact accumulates at Λ = 0. Here we show that while these are very interesting models, they do not properly address the real cosmological constant problem. As we explain, the real problem is not simply to obtain Λ that is small in Planck units in a toy model, but to explain why Λ is much smaller than other mass scales (and combinations of scales) in the theory. Instead, in these toy models, all other particle mass scales have been either removed or sent to zero, thus ignoring the real problem. To this end, we provide a general argument that the included moduli masses are generically of order Hubble, so sending them to zero trivially sends the cosmological constant to zero. We also show that the fundamental Planck mass is being sent to zero, and so the central problem is trivially avoided by removing high energy physics altogether. On the other hand, by including various large mass scales from particle physics with a high fundamental Planck mass, one is faced with a real problem, whose only known solution involves accidental cancellations in a landscape.
MIT Department
Massachusetts Institute of Technology. Center for Theoretical Physics
Massachusetts Institute of Technology. Department of Physics
Terms of Use
Creative Commons Attribution
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1088/1475-7516/2016/06/053
