Superstring Perturbation Theory

Conference Date: 
Wednesday, April 22, 2015 (All day) to Friday, April 24, 2015 (All day)

 

This workshop will discuss the recent progress in perturbative string theory.
 

Sponsorship for this workshop has been provided by:

 

  • Katrin Becker, Texas A&M University
  • Nathan Berkovits, Instituto de Física Teórica
  • Kevin Costello, Perimeter Institute
  • Eric D'Hoker, University of California, Los Angeles
  • Laurent Freidel, Perimeter Institute
  • Michael Green, University of Cambridge
  • Carlos Mafra, University of Cambridge
  • Andrei Mikhailov, Instituto de Física Teórica
  • Arnab Rudra, University of Cambridge
  • Rodolfo Russo, Queen Mary University of London
  • Oliver Schlotterer, Albert Einstein Institute
  • Tibra Ali, Perimeter Institute
  • Ning Bao, Californiat Institute of Technology
  • Katrin Becker, Texas A&M University
  • Melanie Becker, Texas A&M University
  • Nathan Berkovits, Instituto de Física Teórica
  • Lakshya Bhardwaj, Perimeter Institute
  • Chris Brust, Perimeter Institute
  • Eric D'Hoker, University of California, Los Angeles
  • Antonia Frassino, Perimeter Institute
  • Laurent Freidel, Perimeter Institute
  • Davide Gaiotto, Perimeter Institute
  • Jaume Gomis, Perimeter Institute
  • Michael Green, University of Cambridge
  • Shota Komatsu, Perimeter Institute
  • Carlos Mafra, University of Cambridge
  • Andrei Mikhailov, Instituto de Física Teórica
  • Seyed Faroogh Moosavian, Perimeter Institute
  • Miroslav Rapcak, Perimeter Institute
  • Arnab Rudra, University of Cambridge
  • Rodolfo Russo, Queen Mary University of London
  • Oliver Schlotterer, Albert Einstein Institute
  • Ashoke Sen, The Harish-Chandra Research Institute
  • Barak Shoshany, Perimeter Institute
  • Lee Smolin, Perimeter Institute
  • Piotr Tourkine, University of Cambridge
  • Edward Witten, Institute for Advanced Study

 

Wednesday, April 22, 2015

Time

Event

Location

8:30 – 9:00am

Registration

Reception

9:00 – 10:30am

Edward Witten, Institute for Advanced Study
TBA

Alice Room

10:30 – 11:00am

Coffee Break

Bistro – 1st Floor

11:00 – 12:00pm

Eric D’Hoker, University of California, Los Angeles
Modular structure of Type IIB superstrings in the low energy expansion

Alice Room

12:00 – 12:45pm

Discussion 1

Alice Room

12:45 – 2:15pm

Lunch

Reflecting Lounge

2:15 – 3:15pm

Katrin Becker, Texas A&M University
M-theory and G2 manifolds

Alice Room

3:15 – 4:15pm

Kevin Costello, Perimeter Institute
TBA

Alice Room

4:15 – 4:45pm

Coffee Break

Bistro – 1st Floor

4:45 – 5:45pm

Laurent Freidel, Perimeter Institute
Metastring theory and Modular spacetime

Alice Room

Thursday, April 23, 2015

Time

Event

Location

9:00 – 10:30am

Ashoke Sen, The Harish-Chandra Research Institute
1PI Effective Action for  Superstring Perturbation Theory

Alice Room

10:30 – 11:00am

Coffee Break

Bistro – 1st Floor

11:00 – 12:00pm

Arnab Rudra University of Cambridge
Mass renormalization and vacuum shift using Off-shell string theory

Alice Room

12:00 – 12:45pm

Discussion 2

Alice Room

12:45 – 2:15pm

Lunch Break

Bistro – 2nd Floor

2:15 – 3:15pm

Michael Green, University of Cambridge
TBA

Alice Room

3:15 – 3:45pm

Coffee Break

Bistro – 1st Floor

3:45 – 4:45pm

Rodolfo Russo, Queen Mary University of London
Superstring amplitudes in the operator formalism

Alice Room

4:45 – 5:30pm

Discussion 3

Alice Room

5:30pm Onwards

Banquet

Bistro – 2nd Floor

Friday, April 24, 2015

Time

Event

Location

9:00 – 10:30am

Nathan Berkovits, Instituto de Física Teórica
Origin and Applications of the Pure Spinor Formalism

Alice Room

10:30 – 11:00am

Coffee Break

Bistro – 1st Floor

11:00 – 12:00pm

Andrei Mikhailov, Instituto de Física Teórica
Notes on the Type II worldsheet sigma-model

Alice Room

12:00 – 12:45pm

Discussion 4

Alice

12:45 – 2:15pm

Lunch

Bistro – 2nd Floor

2:15 – 3:15pm

Oliver Schlotterer, Albert Einstein Institute
Multiloop SYM and supergravity amplitudes in pure spinor superspace

Alice Room

3:15 – 3:45pm

Coffee Break

Bistro – 1st Floor

3:45 – 4:45pm

Carlos Mafra, University of Cambridge
Explicit multiloop amplitude computations with the pure spinor formalism

Alice Room

4:45 – 5:30pm

Discussion 5

Alice Room

 

 

Katrin Becker, Texas A&M University

M-theory and G2 manifolds

The uplift of classical solutions of M-theory to the quantum theory will be discussed.


Nathan Berkovits, Instituto de Física Teórica

Origin and Applications of the Pure Spinor Formalism

After reviewing its structure and discussing the twistor-like origin of the pure spinor formalism, I will speculate on possible applications for AdS_5xS^5 and M-theory


Eric D'Hoker, University of California, Los Angeles

Modular structure of Type IIB superstrings in the low energy expansion.


Laurent Freidel, Perimeter Institute

Metastring theory and Modular spacetime

In this talk I will review a recent reformulation of string theory which does not rely on an a priori space-time interpretation or a pre-assumption of locality and include form the onset stringy symmetries such as  T-duality.

I will explain how this resulting theory, called metastring, leads to  formulation  where the string is chiral and the target is phase space instead of space-time. I will discuss metastring theory on a flat background and summarize a variety of technical and interpretational ideas. These include  a discussion of moduli space of Lorentzian worldsheets, a generalization of the world sheet renormalisation group, a description of the geometry of phase space, a  study of the symplectic structure and of closed and open boundary conditions, and the string spectrum and operator algebra.

What emerges from these studies is a new quantum notion of space-time that we call modular space-time. This new geometrical concept  is fundamental quantum and modular. It is closely linked with  T-duality and  implements in a precise way a notion of relative locality.


Carlos Mafra, University of Cambridge

Explicit multiloop amplitude computations with the pure spinor formalism
In this talk I will show how to use the pure spinor formalism to compute multiloop string amplitudes, including their precise overall coefficients. I will also discuss the relevance of the recent four-point 3-loop and five-point 2-loop amplitudes for verifying some S-duality predictions.


Andrei Mikhailov, Instituto de Física Teórica

Notes on the Type II worldsheet sigma-model


Arnab Rudra, University of Cambridge

Mass renormalization and vacuum shift using Off-shell string theory 

The conventional on-shell techniques of computing string theory amplitudes is not sufficient to compute mass renormalization of massive states and vacuum shift in string theory. The aim of this talk is to define a suitable off-shell continuation of Polyakov approach. Then this off-shell continuation will be used to compute mass-renormalization and perturbative vacuum shift in string theory.


Rodolfo Russo, Queen Mary University of London

Superstring amplitudes in the operator formalism

The operator formalism provides a constructive approach to superstring amplitudes that has two main virtues: it makes it possible to study explicitly all the degeneration limits and it is flexible enough to work in different setups. I will illustrate these two features in a concrete example: the twisted open string partition function at two loops, which describes the interactions between three D-branes in type II theories.


Oliver Schlotterer, Albert Einstein Institute

Multiloop SYM and supergravity amplitudes in pure spinor superspace

We present a string-inspired method to construct supersymmetric loop integrands for scattering amplitudes in ten-dimensional SYM and supergravity. The kinematic dependence is described in pure spinor superspace and determined from the BRST-symmetry of the underlying pure spinor superstring. We focus on five-point examples at one- and two-loop order which satisfy the BCJ duality between color and kinematics. Hence, the supergravity integrands follow straightforwardly from a double copy construction of the cubic diagrams in SYM. Preliminary examples and open questions at three-loops are mentioned.


Ashoke Sen, The Harish-Chandra Research Institute

1PI Effective Action for  Superstring Perturbation Theory

 

 

Friday Apr 24, 2015
Speaker(s): 

In this talk I will show how to use the pure spinor formalism to compute multiloop string amplitudes, including their precise overall coefficients. I will also discuss the relevance of the recent four-point 3-loop and five-point 2-loop amplitudes for verifying some S-duality predictions.

Scientific Areas: 
 

 

Friday Apr 24, 2015
Speaker(s): 

We present a string-inspired method to construct supersymmetric loop integrands for scattering amplitudes in ten-dimensional SYM and supergravity. The kinematic dependence is described in pure spinor superspace and determined from the BRST-symmetry of the underlying pure spinor superstring. We focus on five-point examples at one- and two-loop order which satisfy the BCJ duality between color and kinematics. Hence, the supergravity integrands follow straightforwardly from a double copy construction of the cubic diagrams in SYM.

Scientific Areas: 
 

 

Friday Apr 24, 2015
 

 

Friday Apr 24, 2015
Speaker(s): 

After reviewing its structure and discussing the twistor-like origin of the pure spinor formalism, I will speculate on possible applications for AdS_5xS^5 and M-theory

Scientific Areas: 
 

 

Thursday Apr 23, 2015
 

 

Thursday Apr 23, 2015
Speaker(s): 

The operator formalism provides a constructive approach to superstring amplitudes that has two main virtues: it makes it possible to study explicitly all the degeneration limits and it is flexible enough to work in different setups. I will illustrate these two features in a concrete example: the twisted open string partition function at two loops, which describes the interactions between three D-branes in type II theories.

Scientific Areas: 
 

 

Thursday Apr 23, 2015
Speaker(s): 
 

 

Thursday Apr 23, 2015
 

 

Thursday Apr 23, 2015
Speaker(s): 

The conventional on-shell techniques of computing string theory amplitudes is not sufficient to compute mass renormalization of massive states and vacuum shift in string theory. The aim of this talk is to define a suitable off-shell continuation of Polyakov approach. Then this off-shell continuation will be used to compute mass-renormalization and perturbative vacuum shift in string theory.

Scientific Areas: 

Pages

Scientific Organizers:

Davide Gaiotto, Perimeter Institute
Jaume Gomis, Perimeter institute
Ashoke Sen, The Harish-Chandra Research Institute
Edward Witten, Institute for Advanced Study