Related papers: String Necklaces and Primordial Black Holes from T…
We study the evolution of cosmic strings taking into account the frictional force due to the surrounding radiation. We consider small perturbations on straight strings, oscillation of circular loops and small perturbations on circular…
We show that in a wide class of string derived models of particle physics, heavy string modes with masses around the GUT scale can serve as a viable dark matter candidate. These heavy string modes wind around specific cycles in the…
The merger of colliding black holes (BHs) should lead to the production of ringdown or quasinormal modes (QNMs), which may very well be sensitive to the state of the interior. We put this idea to the test with a recent proposal that the…
By taking large mass and charge limit of a black hole in string theory we can create arbitrarily large regions where the space-time is approximately flat, but the moduli fields take values different from their asymptotic values. In this…
We argue that cosmic strings with high winding numbers generally form in first-order gauge symmetry breaking phase transitions, and we demonstrate this using computer simulations. These strings are heavier than single-winding strings and…
We present the properties of a cosmic superstring network in the scenario of flux compactification. An infinite family of strings, the (p,q)-strings, are allowed to exist. The flux compactification leads to a string tension that is periodic…
Primordial black holes (PBHs) are known to be produced from collapsing cosmic defects such as domain walls and strings. In this paper we show how PBHs are produced in monopole-string networks.
In this paper the equation of circular loops of cosmic string with periodic tension is investigated in the Minkowski spacetime and Robertson-Walker universe respectively. We find that the cosmic string loops possessing this kind of…
We give some examples in which neglecting the interactions between particles or truncating the description of a black hole to the spherically symmetric mode leads to unphysical results. The restoration of the interactions and higher angular…
In the first part of this talk, I consider some exact string solutions in curved spacetimes. In curved spacetimes with a Killing vector (timelike or spacelike), the string equations of motion and constraints are reduced to the Hamilton…
We in this paper investigate the formation and evolution of primordial black holes (PBHs) in nonsingular bouncing cosmologies. We discuss the formation of PBH in the contracting phase and calculate the PBH abundance as a function of the…
We study cosmic strings in the complex symmetron model, a scalar-tensor theory with a spontaneously broken local $U(1)$ symmetry in low matter density regions. Using numerical simulations, we show that these strings preferentially attach to…
The topic of cosmic strings provides a bridge between the physics of the very small and the very large. They are predicted by some unified theories of particle interactions. If they exist, they may help to explain some of the largest-scale…
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…
This thesis is devoted to trying to find a microscopic quantum description of black holes. We consider black holes in string theory which is a quantum theory of gravity. We find that the ``area law'' black hole entropy for extremal and…
We derive Schwinger-Dyson equations for the Wilson loops of a type IIB matrix model. Superstring coordinates are introduced through the construction of the loop space. We show that the continuum limit of the loop equation reproduces the…
Misner space, also known as the Lorentzian orbifold $R^{1,1}/boost$, is one of the simplest examples of a cosmological singularity in string theory. In this work, the study of weakly coupled closed strings on this space is pursued in…
As a most promising candidate for quantum theory of the gravity, the superstring theory has attracted many researchers including cosmologists. It is expected that the cosmological initial singularity is avoided within the context of the…
We investigate the contribution made by small loops from a cosmic string network as seeds for large-scale structure formation. We show that cosmic string loops are highly correlated with the long-string network on large scales and therefore…
We model the behaviour of a network of interacting (p,q) strings from IIB string theory by considering a field theory containing multiple species of string, allowing us to study the effect of non-intercommuting events due to two different…