Holographic Cosmology and Uncertainty Relation
  It is believed that a primary principle of the theory of quantum gravity is the Holographic Principle according to which a physical system can be described only by degrees of freedom living on its boundary. The generalized covariant formulation of the principle considers the entropy content on truncated light-sheets: light-like hypersurfaces of non-positive expansion orthogonally generated from a boundary. When we construct the truncated light-sheets for cosmological observers we find a general expression for the minimum cosmic time interval from the apparent horizon to verify the holographic prescription; this minimum time is related to quantum effects involved in the entropy computation. Finally, we arrive to the uncertainty relation from the Holographic Principle, which suggests a deep connection between general covariance, entropy bounds and quantum mechanics. 
M. A. Per and A. Segui