cosmological constant problem پراسهی ِ پایای ِ کیهانشناختی parâse-ye pâyâ-ye keyhânšenâxti
*Fr.: problème de la constante cosmologique*
The impressive discrepancy of about 120 orders of magnitude between the theoretical
value of the → *cosmological constant* and its observed value.
→ *Quantum field theory*
interprets the cosmological constant as the density of the
→ *vacuum energy*. This density can be derived from
the maximum energy at which the theory is valid, i.e.
the → *Planck energy* scale (10^{18} GeV).
The theoretical vacuum → *energy density* is
(10^{18} GeV)^{4} = (10^{27} eV)^{4} = 10^{112}
erg cm^{-3}. On the other hand, the observed vacuum energy density is estimated
to be about (10^{-3} eV)^{4} = 10^{-8}
erg cm^{-3}. There is, therefore, a discrepancy of about 120 orders of magnitude. → *cosmological*; → *constant*;
→ *problem*. |