Related papers: Do Global String Loops Collapse to Form Black Hole…
Gravitational waves emitted by distorted black holes---such as those arising from the coalescence of two neutron stars or black holes---carry not only information about the corresponding spacetime but also about the underlying theory of…
An interesting case of string/black hole transition occurs in two-dimensional non-critical string theory dressed with a compact CFT. In these models the high energy densities of states of perturbative strings and black holes have the same…
The amount of the Hawking radiation in Hartle-Hawking vacuum around the Schwarzschild black hole is calculated in the presence of the cloud of virtual-cosmic-string loops near the black hole. Recently, Coleman, Preskill and Wilczek have…
New light fundamental fields are natural candidates for all or a fraction of dark matter. Self-gravitating structures of such fields might be common objects in the universe, and could comprise even galactic halos. These structures would…
Gregory and Laflamme showed that certain nonextremal black strings (and p-branes) are unstable to linearized perturbations. It is widely believed that this instability will cause the black string horizon to classically pinch off and then…
We propose a new scenario for the formation of asteroid-mass primordial black holes (PBHs). Our mechanism is based on the annihilation of the string-wall network associated with the breaking of a $U(1)$ global symmetry into a discrete $Z_N$…
We combine new analysis of the stochastic gravitational wave background to be expected from cosmic strings with the latest pulsar timing array (PTA) limits to give an upper bound on the energy scale of the possible cosmic string network,…
We present observation of large, expanding string loops forming around a heated wire tip embedded in a nematic liquid crystal sample. Loops expand due to convective stretching. This observation leads to a new insight into phenomena which…
We argue that production of charged black hole pairs joined by a cosmic string in the presence of a magnetic field can be analyzed using the Ernst metric. The effect of the cosmic string is to pull the black holes towards each other,…
The existence and stability under linear perturbation of closed timelike curves in the spacetime associated to Schwarzschild black hole pierced by a spinning string are studied. Due to the superposition of the black hole, we find that the…
Gravitons radiated from light, evaporating black holes contribute to the stochastic background of gravitational waves. The spectrum of such emission depends on both the mass and the spin of the black holes, as well as on the redshifting…
The Pulsar timing data from NANOGrav Collaboration has regenerated interest in the possibility of observing stochastic gravitational wave background arising from cosmic strings. In the standard theory, the cosmic string network forms during…
While the outcome of gravitational collapse in classical general relativity is unquestionably a black hole, up to now no full and complete semiclassical description of black hole formation has been thoroughly investigated. Here we revisit…
In the axiverse scenario, a massive scalar field (string axion) forms a cloud around a rotating black hole (BH) by superradiant instability and emits continuous gravitational waves (GWs). We examine constraints on the string axion…
Black holes are popping up all over the place: in compact binary X-ray sources and GRBs, in quasars, AGNs and the cores of all bulge galaxies, in binary black holes and binary black hole-neutron stars, and maybe even in the LHC! Black holes…
It is expected that when the string coupling is taken to be sufficiently small, a black hole turns into a bound state of self-gravitating fundamental strings. This state would be described by winding strings wrapping around the Euclidean…
Quantum aspects of black holes represent an important testing ground for a theory of quantum gravity. The recent success of string theory in reproducing the Bekenstein-Hawking black hole entropy formula provides a link between general…
Earlier attempts to calculate the nonlinear dynamical evolution of Witten type superconducting vacuum vortex defects relied on the use of approximate conducting string models that were too simple to take proper account of the effect of…
If the Universe underwent a cosmic phase transition, it may have left behind a network of cosmic strings. When these strings arise from the breaking of a gauge symmetry, their decay produces a significant stochastic background of…
To derive black hole thermodynamics in any quantum theory of gravity, one must introduce constraints that ensure that a black hole is actually present. For a large class of black holes, the imposition of such ``horizon constraints'' allows…