Talk:Energy condition

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Improvements needed

This is a fair start, but some improvements are needed. See todo list at top of this talk page.---CH 06:02, 23 December 2005 (UTC)[reply]

Violations of the strong energy conditions

A couple of strange comments about them in the article, referenced to a particular textbook.

However, it is clear that such a violation [of the strong condition] would violate the classical regime of general relativity, and one would be required to use an alternative theory of gravity

However, this equation of state [w = -1] only becomes relevant above temperatures of at least 10^12 Kelvin ... The main reason for wanting to falsify the strong energy condition is to avoid the initial singularity in the universe ... The aforementioned suggests that a non-singular universe model would not obey the laws of classical physics at all times in the past.

This sounds wrong, for example, what about the cosmological constant? Though it may just be I don't get what it's trying to say, in which case can we clarify? --174.112.129.234 (talk) 19:10, 2 November 2016 (UTC)[reply]

It sounds as if these statements have been drawn out of their context. I suspect the relevant textbook is making these statements in the context of a specific cosmological model (like LambdaCDM). However, even then it sounds wrong as currently written (e.g. what about the dark energy dominated phase in the future of the LambdaCDM model). Somebody needs to track down this textbook, and figure out what it is actually saying.T R 09:31, 3 November 2016 (UTC)[reply]

Here is a pdf of the textbook.T R 09:38, 3 November 2016 (UTC)[reply]

The statement that dark energy leads to a violation of the strong energy condition is nonsense if dark energy is understood to arise from a non-zero cosmological constant. Energy conditions are conditions on the stress-energy tensor. The cosmological constant is a completely separate contribution to Einstein's equations. Only a charlatan or an ignoramus would confuse the two! — Preceding unsigned comment added by 96.232.96.127 (talk) 22:32, 23 May 2018 (UTC)[reply]