Found 8 result(s)

### 06.02.2018 (Tuesday)

#### AdS3 holographic correlators with heavy states

Regular Seminar Rodolfo Russo (QMUL)

 at: 15:00 City U.room A225 abstract: The AdS/CFT duality maps supersymmetric heavy operators with conformal dimension of the order of the central charge to asymptotically AdS supergravity solutions. I'll show how by studying the quadratic fluctuations around such backgrounds it is possible to derive the 4-point correlators of two light and two heavy states in the supergravity approximation. I'll present some explicit examples in the AdS3 setup relevant for the duality with the D1-D5 CFT and discuss what we can learn in general about correlators among heavy pure states.

### 11.11.2015 (Wednesday)

#### Graduate Lectures: A first introduction to string amplitudes III

Informal Seminar Rodolfo Russo (Queen Mary)

 at: 10:00 QMWroom GO Jones 610 abstract: Lecture 3: An example of mixed open/closed amplitudes

### 10.11.2015 (Tuesday)

#### Graduate Lectures: A first introduction to string amplitudes II

Informal Seminar Rodolfo Russo (Queen Mary)

 at: 10:00 QMWroom GO Jones 610 abstract: Lecture 2: Derivation of the Virasoro-Shapiro amplitude; 4 graviton amplitude in the superstring (no derivation, but discussion of the low and high energy limits)

### 02.11.2015 (Monday)

#### Graduate Lectures: A first introduction to string amplitudes I

Informal Seminar Rodolfo Russo (Queen Mary)

 at: 10:00 QMWroom GO Jones 610 abstract: Lecture 1: Veneziano amplitude: derivation, low and high energy limits

### 04.03.2015 (Wednesday)

#### High energy scattering in string theory

Regular Seminar Rodolfo Russo (Queen Mary University)

 at: 13:15 KCLroom G.01 abstract: The study of high energy amplitudes in string theory provides an interesting arena to study several issues in quantum theories of gravity. I will focus on a conceptually very simple situation where a perturbative graviton scatters against a stack of D-branes and I will discuss phenomena, such as the emergence of tidal forces, the restoration of unitarity through resummation of diagrams and how the Regge behaviour of string theory is crucial to avoid causality violations

### 31.10.2007 (Wednesday)

#### Closed strings and magnetised D-branes in toroidal compactifications

Regular Seminar Rodolfo Russo (Queen Mary)

 at: 13:15 KCLroom 423 abstract: I will reconsider toroidal compactifications of bosonic string theory with particular regard to the phases (cocycles) necessary for a consistent definition of the vertex operators, the boundary states, and the T-duality rules. I will then use these ingredients to compute the planar multi-loop partition function describing the interaction among magnetised or intersecting D-branes. Finally I will examine the degeneration limit of the 2-loop partition function and show that one obtains known and new tree-level 3-point correlators between twist fields.

### 16.03.2006 (Thursday)

#### Intersecting Brane Worlds: a Possible Path from String Theory to Particle Physics

Regular Seminar Rodolfo Russo (QMW)

 at: 14:00 QMWroom 112 abstract: I will discuss the main features of the string compactifications with magnetized (or equivalently intersecting) D-branes and explain why they represent a very interesting setup for phenomenological applications. In particular, I will discuss how to use string techniques to systematically derive brane world effective actions for models with magnetized (or equivalently intersecting) D-branes.

### 01.02.2006 (Wednesday)

#### Brane world effective actions for D-branes with fluxes

Regular Seminar Rodolfo Russo (Queen Mary)

 at: 13:05 KCLroom 423 abstract: I will discuss how to use string techniques to systematically derive brane world effective actions for models with magnetized (or equivalently intersecting) D-branes. In particular, I derive the dependence on all NS-NS moduli of the kinetic terms of the chiral matter in a generic non-supersymmetric brane configurations with non-commuting open string fluxes. Near a N=1 supersymmetric point the effective action contains D and F term breaking terms which can be explicitly computed with string diagrams.