We consider four-dimensional spacetimes (M,g) which obey the Einstein equations G = T, and admit a global spacelike G1 = R isometry group. By means of dimensional reduction and local analyis on the reduced (2 + 1) spacetime, we obtain a sufficient condition on T which guarantees that (M,g) cannot contain apparent horizons. Given any (3 + 1) spacetime with spacelike translational isometry, the n...

Experiments motivated by Bell’s theorem suggest that information is sometimes transferred over spacelike intervals, and claims have been made that the results of these experiments do have this implication. However, the theoretical basis for such claims is usually taken to be Bell’s Theorem, which shows only that if certain predictions of quantum theory are correct, and certain hidden-variables ...

Spacetime must be foliable by spacelike surfaces for the quantum mechanics of matter fields to be formulated in terms of a unitarily evolving state vector defined on spacelike surfaces. When a spacetime cannot be foliated by spacelike surfaces, as in the case of spacetimes with closed timelike curves, a more general formulation of quantum mechanics is required. In such generalizations the trans...

In usual quantum theory, the information available about a quantum system is defined in terms of the density matrix describing it on a spacelike surface. This definition must be generalized for extensions of quantum theory which neither require, nor always permit, a notion of state on a spacelike surface. In particular, it must be generalized for the generalized quantum theories appropriate whe...

In this paper, we study the Dirichlet problem associated to the maximal surface equation. We prove the uniqueness of bounded solutions to this problem in unbounded domain in R. Introduction We consider the Minkowski space-time L3 i.e. R3 with the following pseudoeuclidean metric 〈x, y〉 = x1y1 + x2y2 − x3y3. We define |x| 2 L = 〈x, x〉. A vector is said to be spacelike if |x|2 L > 0 and a surface...

We present two methods to include the asymptotic domain of a background spacetime in null directions for numerical solutions of evolution equations so that both the radiation extraction problem and the outer boundary problem are solved. The first method is based on the geometric conformal approach, the second is a coordinate based approach. We apply these methods to the case of a massless scala...

An interpretation of spacelike singularities in string theory uses target space duality to relate the collapsing Schwarzschild geometry near the singularity to an inflationary cosmology in dual variables. An appealing picture thus results whereby gravitational collapse seeds the formation of a new universe. PACS numbers: 04.70.-s, 11.25.-w String theory is strongly believed to solve the short-d...

Experimentally observed violations of Bell inequalities rule out local realistic theories. Consequently, the quantum state vector becomes a strong candidate for providing an objective picture of reality. However, such an ontological view of quantum theory faces difficulties when spacelike measurements on entangled states have to be described, because time ordering of spacelike events can change...