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The cosmological constant problem and quintessence

2002
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Classical and quantum gravity
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I briefly review the cosmological constant problem and the issue of dark energy (or quintessence). Within the framework of quantum field theory, the vacuum expectation value of the energy momentum tensor formally diverges as $k^4$. A cutoff at the Planck or electroweak scale leads to a cosmological constant which is, respectively, $10^{123}$ or $10^{55}$ times larger than the observed value, $\l/8\pi G \simeq 10^{-47}$ GeV$^4$. The absence of a fundamental symmetry which could set the value of

doi:10.1088/0264-9381/19/13/304
fatcat:a4ymnyqolrg5vp5ysjmrpkhiv4