We consider spacetimes with compact Cauchy hypersurfaces and with Ricci tensor bounded from below on the set of timelike unit vectors, and prove that the results known for spacetimes satisfying the timelike convergence condition, namely, foliation by CMC hypersurfaces, are also valid in the present situation, if corresponding further assumptions are satisfied. In addition we show that the volum...

Dispersion relations provide a powerful tool to describe the electromagnetic form factors of the nucleon both in the spacelike and timelike regions with constraints from unitarity and perturbative QCD. We give a brief introduction into dispersion theory for nucleon form factors and present results from a recent form factor analysis. Particular emphasis is given to the form factors in the timeli...

Timelike T-duality of string theory appears as a symmetry of time evolution in string field theory, exchanging evolution through times t and 1/t, and exchanging boundary states with backgrounds. This is demonstrated by constructing the string field Schrödinger functional, the generator of time evolution, based on Feynman diagram arguments and in analogy with quantum field theory. There the func...

In Euclidean space, the geodesics on a surface of revolution can be characterized by means of Clairaut’s theorem, which essentially says that the geodesics are curves of fixed angular momentum. A similar result is known for three dimensional Minkowski space for timelike geodesics on surfaces of revolution about the time axis. Here, we extend this result to consider generalizations of surfaces o...

It is well-known that the standard no-ghost theorem is valid as long as the background has the light-cone directions. We prove the noghost theorem for the NSR string when only the timelike direction is flat. This is done by the BRST quantization, using the technique of Frenkel, Garland and Zuckerman and our previous results for the bosonic string. The theorem actually applies as long as the tim...

We construct a canonical formulation of general relativity for the case of a timelike foliation of spacetime. The formulation possesses explicit covariance with respect to Lorentz transformations in the tangent space. Applying the loop approach to quantize the theory we derive the spectrum of the area operator of a two-dimensional surface. Its different branches are naturally associated to spac...

We study the nature of entanglement in presence of Deutschian closed timelike curves (D-CTCs) and open timelike curves (OTCs) and find that existence of such physical systems in nature would allow us to increase entanglement using local operations and classical communication (LOCC). This is otherwise in direct contradiction with the fundamental definition of entanglement. We study this problem ...

We consider a class of stationary and axisymmetric wormhole spacetimes that is closely related to, but not identical with, the Teo wormholes. fix point $p$ (observation event) timelike curve $\ensuremath{\gamma}$ (worldline light source), we characterize set all past-oriented lightlike geodesics from to $\ensuremath{\gamma}$. As any such geodesic corresponds an image source on observer's sky, t...

We give a unified derivation of the propagator in the gauges n.A = 0 for n timelike, spacelike or lightlike. We discuss the physical states and other physical questions.

Quantum complex scalar field in the two-dimensional spacetime with closed timelike curves and a time-machine problem Abstract It is considered the quantum complex scalar field which obeys the authomorphic condition in the two-dimensional spacetime with closed timelike curves and the chronology horizon. The renormal-ized stress-energy tensor is obtained. It is shown that the value of the stress-...