# Calculating dark energy (1 Viewer)

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#### jimjohnson

Quoting Kaku in Parallel Worlds (page 12), " If we take the latest theory of subatomic particles and compute the value of dark energy, we find a number that is off by 10 to the 120 power." What is the calculation and the experimental evidence he is referring to?

#### betel

The calculation comes from the zero point energy of the particle fields (similar to the zero point energy in a Harmonic oscillator).
The experimental evidence is the rate of acceleration of expansion of the universe. Measured for example by supernovae surveys.

#### jimjohnson

Thanks, is there a reference that shows the two calculations?

#### betel

For the measured value, the main source is the wmap, e.g. http://arxiv.org/abs/1001.4538" [Broken].

A good review of the problem is http://arxiv.org/pdf/astro-ph/0004075". The main idea for the theoretical calculation is in the first few pages.

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#### bcarpent1228

An interesting approach http://www.calphysics.org/zpe.html" [Broken] found on the CalPhysics site suggests that the gravitational effects of the vacuum field have a phase cutoff point. This allows the large, but constant energy field while limiting the gravitational effect (otherwise we would collapse to sub-atomic size)

Recent work by Christian Beck at the University of London and Michael Mackey at McGill University may have resolved the 120 order of magnitude problem. In that case dark energy is nothing other than zero-point energy. In Measureability of vacuum fluctuations and dark energy and Electromagnetic dark energy they propose that a phase transition occurs so that zero-point photons below a frequency of about 1.7 THz are gravitationally active whereas above that they are not. If this is the case, then the dark energy problem is solved: dark energy is the low frequency gravitationally active component of zero-point energy.

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