QG4 - Loop Quantum gravity, Quantum Geometry, Spin Foams |
Speaker_ |
Majid, Shahn |
Talk _ |
Noncommutative spacetime, VSL and cogravity |
Abstract _ |
We outline the construction of the bicrossproduct model noncommutative spacetime [t,x_i]=i L x_i and the correct formulation of predictions for it including a variable speed of light (VSL) and curvature in momentum space (cogravity) via quantum group Fourier transform. We explain new global effects in the model, notably that any off-shell momentum can be boosted to infinite negative energy by a finite Lorentz transformaton. We explore the issue of sampling with finite momentum bandwidth when momentum space is compact, such as in the noncommutative effective theory for Euclidean 2+1 quantum gravity (where momentum space is a 3-sphere). If time permits, we also explain a general effect whereby sufficiently noncommutative geometries automatically generate an intrinsic `time' or evolution. |