A charge operator is constructed for a quantum field theory with an abelian discrete gauge
symmetry, and a non-local order parameter is formulated that specifies how the gauge …

A black hole may carry quantum numbers that are not associated with massless gauge
fields, contrary to the spirit of the “no-hair” theorems. We describe in detail two different types …

Considerable interest has recently been expressed in (static spherically symmetric) black
holes in interaction with various classical matter fields (such as electromagnetic fields …

We provide a new exact solution of the Einstein equations which generalize the
noncommutative geometry-inspired Schwarzschild metric, we previously obtained. We …

The 4-dimensional theory of a 1-form Abelian gauge field A coupled to a 2-form
(antisymmetric tensor) potential B is studied. The two gauge invariances of the theory admit …

In this paper, we present the weak deflection angle in a Schwarzschild black hole of mass m
surrounded by the dark matter of mass M and thickness Δr s. The Gauss-Bonnet theorem …

We consider corrections to Einstein gravity arising from the inclusion of Lorentz Chern-
Simons terms, as well as Gauss-Bonnet terms, in a theory containing dilatons and Kalb …

We consider axion fields with Lorentz Chern-Simons coupling to gravity. In Kerr black hole
background metrics this coupling gives a non-vanishing source term for the axion field. For …

In this paper, we examine the effect of dark matter to a Kerr black hole of mass m. The metric
is derived using the Newman-Janis algorithm, where the seed metric originates from the …

In this study, we present an exact dirty/hairy black hole solution in the context of gravity
coupled minimally to a nonlinear electrodynamic (NED) and a Dilaton field. The NED model …