Defense of de Sitter: Exploring the Dual Arrows of Time in Inflationary Reality

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In summary, the concept of de Sitter space has been used in the defense of inflationary theory, specifically in explaining the dual arrows of time. De Sitter space is a mathematical model of space-time that describes an accelerating universe, which is a key aspect of inflationary theory. This model also suggests that the universe has a past and a future, with time moving in opposite directions within different regions. The study of de Sitter space has provided valuable insights into the nature of our universe and its evolution, supporting the validity of inflationary theory.
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If Aguirre and Gratton's version of dual arrows of time in an inflationary reality (at http://arxiv.org/pdf/gr-qc/0301042v2.pdf) corresponds to our own, the past and future began their ongoing separation an infinite time ago, and, with its past spacetime contracting (as per Vilenkin's reading of AG, at http://arxiv.org/pdf/1305.3836v2.pdf), the most remote past is infinitely remote. It seems to me that, with the present spacetime presumably expanding into an infinitely remote future, the net curvature of the space between any objects having mass, in anyone of two pairs of such objects each on an opposite side (past or future) of that reality from the other, would (if averaged between both pairs of them to yield amounts of mass) consequently add up to the zero characterizing a flat (Minkowski) vacuum, but the mass of either pair during its instant of passage through the present either would yield, or would've been yielding, the net positive figure characterizing de Sitter space.

I'm thinking this could be either more or less plainly the case in the more generally accepted versions of inflation as "eternal to the future" (which Aguirre logically describes as "semi-eternal inflation"), depending on their account of the origin of the space-curving mass.

I'm mainly wanting to verify whether my assumption of the "true" (meaning "minimum mass") vacuum as having mass is correct, because of a conclusion (based on the Many Worlds interpretation of QM and contained in the recent paper "De Sitter Space Without Dynamical Quantum Fluctuations", at http://arxiv.org/abs/1405.0298) that inflation would generically continue into the future only if the true vacuum is de Sitter. (In defense of the scientific method's popularity in its competition with other philosophies or ideologies equally engaged in various attempts at resolving our world's current social problems, I should mention the fact that the paper does allow for the universes described by an arbitrarily small number of branches of the wavefunction to inflate eternally, which has the interesting effect of explaining how any individual might involuntarily wander discontinuously between different settings, whereas generically eternal inflation would associate recurrences of every individual with a setting, identical to their oldest or original environment, that would tend to appear at random intervals.)

However, it also occurs to me that a presumed dependence of the simultaneity of events perceived by different observers on their relative directions of motion (associated with Special Relativity by Brian Greene, on p.504 in The Fabric of the Cosmos) might not hold if gravity (absent in SR) could be taken into account. Consequently, a second question I have is whether a successful quantum theory of gravity would be expected to resolve such issues as the Train Paradox, which are routinely described in popularizations of SR and might, through the "block universe" view of time, allow an overlapping of realities that might give greater "weight" to either the past or the future, perhaps admitting Minkowski space to physicality, either at the origin of time or at its center.

Any opinions on either of these two questions would be much appreciated.
 
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slatts said:
it also occurs to me that a presumed dependence of the simultaneity of events perceived by different observers on their relative directions of motion (associated with Special Relativity by Brian Greene, on p.504 in The Fabric of the Cosmos) might not hold if gravity (absent in SR) could be taken into account.

This is not correct. The relativity of simultaneity is certainly still present in GR, with gravity included.
 
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PeterDonis said:
This is not correct. The relativity of simultaneity is certainly still present in GR, with gravity included.

I see you're right: Looking up my source (Vilenkin's "The Principle of Mediocrity"), it only says that "time and simultaneity are not uniquely defined in General Relativity".
 
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FAQ: Defense of de Sitter: Exploring the Dual Arrows of Time in Inflationary Reality

What is "Defense of de Sitter" all about?

"Defense of de Sitter" is a scientific concept that seeks to explore the dual arrows of time in the context of inflationary reality. It focuses on the relationship between the expansion of our universe (represented by the de Sitter space) and the direction of time, and aims to defend the idea that time has a definite direction in this scenario.

How does this concept relate to inflationary theory?

Inflationary theory, which proposes that the universe underwent a rapid period of expansion in its early stages, is closely connected to the idea of de Sitter space. The expansion in inflationary theory is analogous to the expansion of de Sitter space, and both have been observed to have a preferred direction in time. "Defense of de Sitter" seeks to further explore this relationship and provide a better understanding of the concept of time in this scenario.

What is meant by the "dual arrows of time" in this context?

The dual arrows of time refer to the two distinct but interconnected ways in which time is perceived in the context of de Sitter space and inflationary theory. On one hand, there is the arrow of time that represents the expansion of the universe, and on the other hand, there is the arrow of time that reflects the flow of time in our everyday experience. "Defense of de Sitter" aims to reconcile these two arrows and provide a unified understanding of time in this context.

What evidence supports the concept of "Defense of de Sitter"?

There is significant observational and theoretical evidence that supports the idea of a preferred direction of time in de Sitter space and inflationary theory. Observations of the cosmic microwave background radiation, as well as theoretical models, have shown that the expansion of the universe and the direction of time are closely linked. "Defense of de Sitter" builds upon this evidence and provides a deeper understanding of this relationship.

How does "Defense of de Sitter" contribute to our understanding of the universe?

"Defense of de Sitter" has the potential to significantly advance our understanding of the universe, particularly in relation to the concept of time. By exploring the dual arrows of time and their connection to de Sitter space and inflationary theory, this concept could provide new insights into the fundamental nature of time and the universe as a whole.

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