Related papers: Modave Lectures on Horizon-Size Microstructure, Fu…
The aim of this work is to present the black hole information problem and discuss the assumptions and hypotheses necessary for its formulation. As the problem arises in the framework of semiclassical gravity, we first review the necessary…
We consider a black hole with a stretched horizon as a toy model for a fuzzball microstate. The stretched horizon provides a cut-off, and therefore one can determine the normal (as opposed to quasi-normal) modes of a probe scalar in this…
Black holes are among the most exciting phenomena predicted by General Relativity and play a key role in fundamental physics. Many interesting phenomena involve dynamical black hole configurations in the high curvature regime of gravity. In…
We present three-dimensional magnetohydrodynamic (MHD) simulations of superbubbles, to study the importance of MHD effects in the interpretation of images from recent surveys of the Galactic plane. These simulations focus mainly on…
For centuries, bubbles have fascinated artists, engineers, and scientists alike. In spite of century-long research on them, new and often surprising bubble phenomena, features, and applications keep popping up. In this paper I sketch my…
We study microstates of the three dimensional black hole obtained by quantizing topologically non-trivial geometries behind the event horizon. In chiral gravity these states are found by quantizing the moduli space of bordered Riemann…
In this essay we introduce a theoretical framework designed to describe black hole dynamics. The difficulties in understanding such dynamics stems from the proliferation of scales involved when one attempts to simultaneously describe all of…
The presented paper is a review of papers on the microcosm physics geometrization in the last twenty years. These papers develop a new direction of the microcosm physics. It is so-called geometric paradigm, which is alternative to the…
This thesis is devoted to the study of Quantum Field Theories (QFT) on fuzzy spaces. Fuzzy spaces are approximations to the algebra of functions of a continuous space by a finite matrix algebra. In the limit of infinitely large matrices the…
We informally review the construction of spacetime geometries with multifractal and, more generally, multiscale properties. Based on fractional calculus, these continuous spacetimes have their dimension changing with the scale; they display…
We report the existence of novel static spherical black-hole solutions in a vector-tensor gravitational theory called the bumblebee gravity model which extends the Einstein-Maxwell theory by allowing the vector to nonminimally couple to the…
We revisit the relation between fuzzball solutions and D1-D5 microstates. A consequence of the fact that the R ground states (in the usual basis) are eigenstates of the R-charge is that only neutral operators can have non-vanishing…
In these lectures I give an introduction to the quantum physics of black holes, including recent developments based on quantum information theory such as the firewall paradox and its various cousins. I also give an introduction to…
This talk gives a brief introduction to black hole horizons and their role in black hole thermodynamics. In particular a distinction is made between quasi-locally defined horizons and event horizons. Currently some new techniques have led…
The information paradox can be resolved if we recognize that the wavefunctional in gravity $\Psi[g]$ should be considered on the {\it whole} of superspace, the space of possible $g$. The largeness of the Bekenstein entropy implies a vast…
We review the interplay of fuzzy field theories and matrix models, with an emphasis on the phase structure of fuzzy scalar field theories. We give a self-contained introduction to these topics and give the details concerning the saddle…
A historical review of our understanding of bulges is first presented, highlighting similarities and differences between bulges and ellipticals. Then, some topics of current interest are reviewed, bypassing stellar population questions and…
Quivers, gauge theories and singular geometries are of great interest in both mathematics and physics. In this note, we collect a few open questions which have arisen in various recent works at the intersection between gauge theories,…
Solitonic scalar field configurations are studied in a theory coupled to gravity. It is found that non-topological solitons, Q-balls, are present in the theory. Properties of gravitationally self coupled Q-balls are studied by analytical…
In the coming decade, gravitational waves will convert the study of general relativistic aspects of black holes and stars from a largely theoretical enterprise to a highly interactive, observational/theoretical one. For example,…