Found 3 result(s)

24.04.2025 (Thursday)

Modern aspects of the black hole/string correspondence

Regular Seminar Marija Tomasevic (Unversity of Amsterdam)

at:
14:00 QMUL
room G. O. Jones 610
abstract:

I will review the basic story behind the black hole/string correspondence, its advantages, and its limits. I will then summarize some recent progress on this topic and go over several possible open directions.

19.02.2025 (Wednesday)

Stringy Gregory-Laflamme

Regular Seminar Marija Tomasevic (Amsterdam U)

at:
13:30 IC
room H503
abstract:

Thin enough black strings are unstable to growing ripples along their length, eventually pinching and forming a naked singularity on the horizon. We investigate how string theory can resolve this singularity. First, we study the string-scale version of the static non-uniform black strings that branch off at the instability threshold: "string-ball strings", which are linearly extended, self-gravitating configurations of string balls obtained in the Horowitz-Polchinski (HP) approach to near-Hagedorn string states. We construct non-uniform HP strings in spatial dimensions d≤6 and show that, as the inhomogeneity increases, they approach localized HP balls. We also examine the thermodynamic properties of the different phases in the canonical and microcanonical ensembles. We find that, for a sufficiently small mass, the uniform HP string will be stable and not evolve into a non-uniform or localized configuration. Building on these results and independent evidence from the evolution of the black string instability with α' corrections, we propose that, at least in d=4,5, string theory slows and eventually halts the pinching evolution at a classically stable stringy neck. In d≥6 this transition is likely to occur into a puffed-up string ball. The system then enters a slower phase in which the neck gradually evaporates into radiation. We discuss this scenario as a framework for understanding how string theory resolves the formation of naked singularities.

25.01.2023 (Wednesday)

Holographic duals to evaporating black holes

Regular Seminar Marija Tomasevic (Ecole Polytechnique, CPHT)

at:
13:45 KCL
room K0.16
abstract:

We describe the dynamical evaporation of a black hole as the classical evolution in time of a black hole in an Anti-de Sitter braneworld. A bulk black hole whose horizon intersects the brane yields the classical bulk dual of a black hole coupled to quantum conformal fields. The evaporation of this black hole happens when the bulk horizon slides off the brane, making the horizon on the brane shrink. We use a large-D effective theory of the bulk Einstein equations to solve the time evolution of these systems. With this method, we study the dual evaporation of a variety of black holes interacting with colder radiation baths. We also obtain the dual of the collapse of holographic radiation to form a black hole on the brane.