Positron annihilation spectroscopy is particularly suitable for studying vacancy-type
defects<? format?> in semiconductors. Combining state-of-the-art experimental and …

Lovelock theory is a natural extension of Einstein theory of gravity to higher dimensions, and
it is of great interest in theoretical physics as it describes a wide class of models. In …

Astrophysical black hole candidates, although long thought to have a horizon, could be
horizonless ultracompact objects. This intriguing possibility is motivated by the black hole …

Measuring the Doppler broadening of the positron annihilation radiation or the angular
correlation between the two annihilation gamma quanta reflects the momentum distribution …

The geometry of a spacetime containing a wormhole generated by a spherically symmetric
electric field is investigated in detail. These solutions arise in high-energy extensions of …

It was previously shown by one of us that in any static, non-globally-hyperbolic, spacetime, it
is always possible to define a sensible dynamics for a Klein–Gordon scalar field. The …

Naked singularities are hypothetical astrophysical objects, characterized by a gravitational
singularity without an event horizon. Penrose has proposed a conjecture, according to which …

We study spherically symmetric configurations of the quadratic f (R) gravity [f (R)= RR 2/6 μ
2]. In the case of a purely gravitational system, we have fully investigated the global …

We investigate a family of solutions of type-IIB supergravity which asymptotically approach
AdS5× S5 but contain a non-constant dilaton and volume scalar for the five-sphere. These …

Though the cosmic censorship conjecture states that spacetime singularities must be hidden
from an asymptotic observer by an event horizon, naked singularities can form as the end …