Triangle Seminars
Wednesday, 3 May 2017
Diffusion and chaos in holographic systems at non-zero density
Richard Davison
(Harvard)
Abstract:
Recent work has uncovered relations between the rate at which chaotic behaviour spreads in strongly interacting quantum systems, and the diffusivities of certain processes in these systems. Focusing mainly on holographic examples, I will explore the extent to which these relations hold in states at non-zero density, where the diffusion of charge and energy are no longer independent processes.
Recent work has uncovered relations between the rate at which chaotic behaviour spreads in strongly interacting quantum systems, and the diffusivities of certain processes in these systems. Focusing mainly on holographic examples, I will explore the extent to which these relations hold in states at non-zero density, where the diffusion of charge and energy are no longer independent processes.
Posted by: IC
The 43rd Edwards Lecture: Carlo Rubbia (Nobel Laureate and Former Director General of CERN)
Carlo Rubbia
(CERN)
Abstract:
"The Role of Elementary Particle Accelerators"
http://www.city.ac.uk/events/2017/may/edwards-lecture-the-role-of-elementary-particle-accelerators
(Public lecture and Colloquium)
"The Role of Elementary Particle Accelerators"
http://www.city.ac.uk/events/2017/may/edwards-lecture-the-role-of-elementary-particle-accelerators
(Public lecture and Colloquium)
Posted by: oxford
Friday, 5 May 2017
The tale of two dilatons
Paolo Di Vecchia
(NBI/Nordita)
Abstract:
In this talk we will discuss how gauge invariance fixes the soft behavior of massless particles as photons, gluons, gravitons, dilatons and Kalb-Ramond field. We will then check these results in string theory and we will show that the subsubleading behavior for gravitons includes string corrections in the bosonic and heterotic strings, but not in superstring. They are consequence of the fact that the three-graviton amplitude has string corrections with respect to the field theoretical one. It turns out, instead, that the soft behavior of the dilaton has no string corrections and, in particular, involves the generators of dilatations and special conformal transformations. We then study the soft behavior of the Goldstone boson, called in the literature also dilaton, that one gets when one breaks spontaneously the conformal symmetry and we show that its soft behavior is very similar, but not identical, to that of the string dilaton.
In this talk we will discuss how gauge invariance fixes the soft behavior of massless particles as photons, gluons, gravitons, dilatons and Kalb-Ramond field. We will then check these results in string theory and we will show that the subsubleading behavior for gravitons includes string corrections in the bosonic and heterotic strings, but not in superstring. They are consequence of the fact that the three-graviton amplitude has string corrections with respect to the field theoretical one. It turns out, instead, that the soft behavior of the dilaton has no string corrections and, in particular, involves the generators of dilatations and special conformal transformations. We then study the soft behavior of the Goldstone boson, called in the literature also dilaton, that one gets when one breaks spontaneously the conformal symmetry and we show that its soft behavior is very similar, but not identical, to that of the string dilaton.
Posted by: QMW