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Suekdccia

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- Entropy reversal in an infinite static universe?

As far as I know, entropy could be reversed by the Poincaré recurrence theorem if it had a finite horizon given by some amount of vacuum energy causing an accelerating expansion.

However, I found this lecture by Leonard Susskind () where he tells a way through which the vacuum could decay into a vacuum state with no energy and therefore no expansion would occur. In this case, we would have a static universe. However, he says that in this case no recurrence would take place.

But, in this answer to one similar question on another physics-discussion site (Could any new structures be formed after the heat death of the universe?), it says that in a static universe with no accelerated expansion (and therefore no cosmological constant) the Poincarré recurrence theorem would hold. And also, I understand that in a non-accelerating expanding universe there would be no maximal entropy reached so the recurrence should occur.

So, what am I missing here?

However, I found this lecture by Leonard Susskind () where he tells a way through which the vacuum could decay into a vacuum state with no energy and therefore no expansion would occur. In this case, we would have a static universe. However, he says that in this case no recurrence would take place.

But, in this answer to one similar question on another physics-discussion site (Could any new structures be formed after the heat death of the universe?), it says that in a static universe with no accelerated expansion (and therefore no cosmological constant) the Poincarré recurrence theorem would hold. And also, I understand that in a non-accelerating expanding universe there would be no maximal entropy reached so the recurrence should occur.

So, what am I missing here?