QG2 - Quantum Gravity Phenomenology |
|
Speaker |
Kothawala, Dawood |
|
Coauthors |
|
| Talk Title |
The Small Scale Structure Of Spacetime |
|
Abstract |
Existence of a lower bound, say L, to spacetime intervals arises very generically when one attempts to combine the basic principles of quantum theory and general relativity. I argue that incorporating such a length scale in a Lorentz covariant manner requires a description of spacetime geometry in terms of non-local bi-tensors rather than the conventional metric tensor. I show how such a description can be achieved by reconstructing the spacetime using the Synge world function and the van Vleck determinant. Using these, I demonstrate that the same non-analytic structure of the reconstructed spacetime which renders a perturbative expansion in L meaningless, will also generically leave a non-trivial “relic” in the limit L → 0. I present specific results where such a relic term is manifest, and discuss several implications of the same. Specifically, I will discuss how these results: (i) suggest a different description of gravitational dynamics from the conventional one based on the Einstein-Hilbert lagrangian, (ii) imply a dimensional reduction to D = 2 at small scales, (iii) support the idea that the cosmological constant Λ might be a non-local vestige of the small scale structure of spacetime. I will conclude by discussing the ramifications of these ideas in the context of quantum gravity, and what it implies for the (semi-)classical limit of any quantum gravity framework. The talk will be essentially based on work that has been systematically developed in: 1307.5618, 1405.4967, 1408.3963, 1503.03793, 1507.05669. |
|
Talk view |
|
|
|
|