Geometry as the Classical Limit: Examples and Analogies in Physics

[ephen wilb]

Can anyone give other examples where the geometry is the classical limit of another theory? I can give one. For example. The body curves of a woman is geometric.. so the geometry is the result of the bones and internal structure of the physical body. Likewise, in General Relativity, could the geometric part also comes from some other dynamics? Can you give other systems where such occurs that geometry is just a large scale description of an underlying phenomenon?

 

[robphy]

Equilibrium thermodynamics (and its geometrical structure) could be seen as a limiting case of statistical mechanics.

Continuum mechanics (and its geometrical structure) could be seen as a limiting case of a many-particle atomic theory

 

[WannabeNewton]

Likewise, in General Relativity, could the geometric part also comes from some other dynamics?

Yes, this is the content of both string theory and loop quantum gravity.

 

[ephen wilb]

Years ago I was asking in the google newsgroup why is the geometry curving in GR. The physicists mostly give me Bohr Line's about "It is wrong to think that the task of physics is to find out how nature is. Physics concerns what we can say about nature." Therefore it seems not a frame of mind to ask if the geometry is caused by other dynamics.. But yesterday I learned from the above previous message that String Theory and Loop QG content is precisely this exploration that the geometry may come from other dynamics. Is this not disobeying or violating Bohr statement? Can't we just say, the geometry curves and it is gravity. End of story? Remember in quantum mechanics.. physics don't ask why there is randomness... but in GR.. why is it right to ask what's or what it's curving?