Triangle Seminars
Wednesday, 14 Dec 2016
On branes and instantons
Ruben Minasian
(IPhT Saclay)
Abstract:
I’ll review old and new aspects of deformed instanton equations derived from D-branes.
I’ll review old and new aspects of deformed instanton equations derived from D-branes.
Posted by: IC
Scrambling time in eternal BTZ black hole
Andrius Stikonas
(Edinburgh U.)
Abstract:
It is usually hard to compute entanglement entropy and mutual
information for conformal field theories (CFT). Ryu-Takayanagi proposals allows
us to find the same quantities using calculations in gravity. In this talk I
will show how to find holographic entanglement entropy and scrambling time for
BTZ black hole perturbed by a heavy (backreacting) particle. Holographic bulk
description improves on the shock-wave approximation in 3d bulk dimensions. I
will also discuss my work to generalize this calculation to the rotating BTZ
black hole.
It is usually hard to compute entanglement entropy and mutual
information for conformal field theories (CFT). Ryu-Takayanagi proposals allows
us to find the same quantities using calculations in gravity. In this talk I
will show how to find holographic entanglement entropy and scrambling time for
BTZ black hole perturbed by a heavy (backreacting) particle. Holographic bulk
description improves on the shock-wave approximation in 3d bulk dimensions. I
will also discuss my work to generalize this calculation to the rotating BTZ
black hole.
Posted by: QMW
Thursday, 15 Dec 2016
Self-oscillation
Alejandro Jenkins
(Costa Rica U.)
Abstract:
A self-oscillator generates and maintains a periodic motion at the expense of an energy source with no corresponding periodicity. Small perturbations about equilibrium are amplified. Non-linearity accounts for steady-state oscillations and for the ability of coupled self-oscillators to exhibit both spontaneous synchronisation (“entrainmentâ€) and chaos. The theory of self-oscillators has achieved its greatest sophistication in mathematical control theory and in the study of ordinary differential equations. I shall explain in this talk how an understanding better suited to physicists can be founded on considerations of energy, efficiency, and thermodynamic irreversibility.
After reviewing the key differences between forced a parametric resonances on the one hand and self-oscillators on the other, I will comment on how a physical approach to the theory of self-oscillators throws new light on flow instabilities. I will close by describing mechanical and hydrodynamic analogs of the Zel’dovich superradiance of rotating black holes, a subject of considerable interest in high-energy physics today.
A self-oscillator generates and maintains a periodic motion at the expense of an energy source with no corresponding periodicity. Small perturbations about equilibrium are amplified. Non-linearity accounts for steady-state oscillations and for the ability of coupled self-oscillators to exhibit both spontaneous synchronisation (“entrainmentâ€) and chaos. The theory of self-oscillators has achieved its greatest sophistication in mathematical control theory and in the study of ordinary differential equations. I shall explain in this talk how an understanding better suited to physicists can be founded on considerations of energy, efficiency, and thermodynamic irreversibility.
After reviewing the key differences between forced a parametric resonances on the one hand and self-oscillators on the other, I will comment on how a physical approach to the theory of self-oscillators throws new light on flow instabilities. I will close by describing mechanical and hydrodynamic analogs of the Zel’dovich superradiance of rotating black holes, a subject of considerable interest in high-energy physics today.
Posted by: QMW