Calabi-Yau manifold + ideal gas + point disturbance?

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Discussion Overview

The discussion explores the concept of filling a Calabi-Yau manifold with an ideal gas and the implications of sound waves resulting from a point disturbance within this closed space. Participants consider theoretical aspects, including the Ricci-flat condition of Calabi-Yau manifolds and its potential influence on sound propagation.

Discussion Character

  • Exploratory, Technical explanation, Conceptual clarification

Main Points Raised

  • One participant questions whether it makes sense to consider sound waves in a Calabi-Yau manifold filled with an ideal gas, referencing the Ricci-flat condition.
  • Another participant suggests that if Calabi-Yaus are viewed as models of extra dimensions, the gas would not remain confined to a single manifold due to the presence of neighboring spaces.
  • A different viewpoint posits that a brane wrapping one of the Calabi-Yaus could allow for a gas of open strings, linking the thermodynamics of the black hole to the string gas dynamics.
  • One participant speculates that the wave front from a point disturbance in a gas-filled Calabi-Yau might initially expand as a five-dimensional spherical shell, acknowledging the complexity of sound propagation in curved spaces.
  • Another participant expresses uncertainty about the specific implications of the Ricci-flat condition on sound propagation, while drawing a comparison to a two-dimensional torus as an example of a Calabi-Yau space.

Areas of Agreement / Disagreement

Participants express various hypotheses and models regarding the behavior of sound waves in a Calabi-Yau manifold, but no consensus is reached on the implications or outcomes of these ideas.

Contextual Notes

The discussion includes speculative elements and relies on theoretical constructs, with limitations regarding the assumptions made about the nature of sound propagation in curved spaces and the behavior of gases in such manifolds.

Spinnor
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Because it is a closed space, can it make sense to fill a Calabi_Yau manifold with an ideal gas and consider waves from a point disturbance?

Would the Ricci-flat condition of Calabi-Yau manifolds have anything to say about possible sound waves?

Thanks!
 
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If you are thinking of Calabi-Yaus in the usual context (as a model of the extra dimensions), remember that there is a copy of the Calabi-Yau at every point in macroscopic space-time. So if you had a "gas" filling just one of these CYs, the "molecules" would spill out into neighboring space.

One way around this, is to suppose that there is a brane wrapping one of the CYs, and that the gas consists of open strings attached to the brane. Some stringy black holes are like this - wrapped branes with a gas of attached strings. In such a case, the thermodynamics of the black hole comes from the thermodynamics of this string gas.
 
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mitchell porter said:
If you are thinking of Calabi-Yaus in the usual context

Just a single Calabi-Yau manifold plus time. Of course this can only be done as a thought experiment.

So with our gas filled Calabi-Yau space I would expect that the wave front from a point disturbance would initially expand as a 5 dimensional spherical shell? Then things get complicated but I thought that the Ricci-flat condition of these spaces might allow one to make some general statements about sound propagation?

I guess sound propagation in curved spaces is complicated.

Thanks!
 
Spinnor said:
I thought that the Ricci-flat condition of these spaces might allow one to make some general statements about sound propagation?
It probably does but I don't know what they are.

A two-dimensional torus with a flat metric is a Calabi-Yau space. So an ancient wraparound video-game like "Asteroids" is an example of "physics in a Calabi-Yau space".
 
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