### Conveners

#### 12 - Beyond Quantum Field Theory Approaches (including String Theories)

- Martin Schnabl (Prague)

#### 12 - Beyond Quantum Field Theory Approaches (including String Theories)

- Kostas Skenderis (Amsterdam)

#### 12 - Beyond Quantum Field Theory Approaches (including String Theories)

- Iosif Bena (CEA-Saclay)

#### 12 - Beyond Quantum Field Theory Approaches (including String Theories)

- Alessandro Tomasiello (Milan Bicocca University)

Prof.
Gregory Korchemsky
(CEA Saclay)

7/22/10, 9:00 AM

12 - Beyond Quantum Field Theory Approaches (including String Theories)

Parallel Session Talk

I will review a recent progress in computing scattering amplitudes in maximally supersymmetric Yang-Mills theory. In addition to the conventional symmetry of the underlying Lagrangian, the scattering amplitudes in this theory exhibit a new, dual superconformal symmetry. This symmetry is powerful enough to completely determine the scattering amplitudes for arbitrary coupling in a suitably defined limit.

Henrik Johansson
(IPhT CEA Saclay)

7/22/10, 9:22 AM

12 - Beyond Quantum Field Theory Approaches (including String Theories)

Parallel Session Talk

In a previous paper we observed that (classical) tree-level gauge theory amplitudes can be rearranged to display a duality between color and kinematics. Once this is imposed, gravity amplitudes are obtained using two copies of gauge-theory diagram numerators. Here we suggest that this duality persists to all quantum loop orders and can thus be used to obtain multi-loop gravity amplitudes...

Pierre Vanhove
(IPHT CEA/Saclay & IHES)

7/22/10, 9:44 AM

12 - Beyond Quantum Field Theory Approaches (including String Theories)

Parallel Session Talk

We show that different color-ordered tree-level amplitudes in gauge theories satisfy monodromy relations. These relations imply the existence of minimal basis of amplitude and provide the numerator factors of the amplitude for a parametrisation of the tree-level amplitude using only cubic vertices. Applications to supergravity amplitudes follow straightforwardly through the KLT-relations....

Slava Rychkov
(ENS & Jussieu)

7/22/10, 10:06 AM

12 - Beyond Quantum Field Theory Approaches (including String Theories)

Parallel Session Talk

A classic result of 4D CFT says that, in a unitary theory, a scalar operator of dimension d=1 is free. We will present results showing in which sense a scalar O of dimension d>1 but close to 1 is "nearly free". Namely, we analyze the OPE OxO of such a scalar with itself and show that 1) there must be a scalar of dimension 2+O(sqrt(d-1)) in this OPE; 2) in the d->1 limit, no scalars of...

Dr
Nick Halmagyi
(CEA)

7/22/10, 11:00 AM

12 - Beyond Quantum Field Theory Approaches (including String Theories)

Parallel Session Talk

Constructing models of meta-stable vacua in supersymmetric theories is a crucial task for string phenomenology. It has been conjectured that anti-D3 branes in the Klebanov-Strassler background indeed produce such a supersymmetry breaking scenario. In this talk I will outline the results of a supergravity calculation which represents the backreaction of such anti-D3 branes and discuss the...

John Estes
(ENS)

7/22/10, 11:22 AM

12 - Beyond Quantum Field Theory Approaches (including String Theories)

Parallel Session Talk

In a string theory framework, one may unambiguously compute the free-energy density including the vacuum energy, in backgrounds with spontaneously broken supersymmetry. For certain classes of models, the resulting backreaction induces a cosmological evolution which mimics a radiation dominated expansion. The supersymmetry breaking scale is attracted to the temperature scaleand the internal...

Prof.
Michela Petrini
(CNRS/LPTHE)

7/22/10, 11:44 AM

12 - Beyond Quantum Field Theory Approaches (including String Theories)

Parallel Session Talk

We discuss supersymmetry breaking compactifications in type IIA and we propose a new treatment of non-supersymmetric sources: for space-time filling supersymmetric branes, the energy density is minimized by a pullback of a special form given by a pure spinor. We propose to extremise the combined bulk-brane energy density by replacing the DBI action by a pullback of a polyform from the bulk,...

Dr
Aurelien Barrau
(LPSC Laboratoire de Physique Subatomique et de Cosmologie (LPSC))

7/22/10, 12:06 PM

12 - Beyond Quantum Field Theory Approaches (including String Theories)

Parallel Session Talk

Loop quantum gravity is, together with string theory, one on the major candidate approach to quantize gravity. It provides a framework which allows for a non-perturbative and background-independant canonical quantization of general relativity. In this talk, I will briefly go through the basic conceptual groundings of the theory and switch to the latests developments associated with its...

Prof.
Erik Verlinde
(ITP, University of Amsterdam)

7/22/10, 2:00 PM

12 - Beyond Quantum Field Theory Approaches (including String Theories)

Parallel Session Talk

Starting from first principles and general assumptions Newton's law of gravitation is shown to arise naturally and unavoidably in a theory in which space is emergent through a holographic scenario. Gravity is explained as an entropic force caused by changes in the information associated with the positions of material bodies. A relativistic generalization of the presented arguments directly...

Ashoke Sen
(Harish-Chandra Research Institute)

7/22/10, 2:42 PM

12 - Beyond Quantum Field Theory Approaches (including String Theories)

Parallel Session Talk

In this talk we shall describe how quantum entropy function formalism allows us to compute classical, perturbative and non perturbative contribution to the extremal black hole entropy. We shall also compare the results with microscopic results.

Dr
Sheer El-Showk
(CEA Saclay)

7/22/10, 3:03 PM

12 - Beyond Quantum Field Theory Approaches (including String Theories)

Parallel Session Talk

We quantize a family of smooth multicentered supergravity solutions generating (micro)states of a large supersymmetric black hole in five dimensions. Certain special states are found to suffer from unexpected, macroscopically large quantum fluctuations in the near horizon region of the putative black hole. This breakdown in effective field theory near the horizon may be relevant in resolving...

Dr
Martin Schnabl
(Institute of Physics AS CR, Prague)

7/22/10, 3:24 PM

12 - Beyond Quantum Field Theory Approaches (including String Theories)

Parallel Session Talk

We review recent progress in finding and analyzing classical solutions of open string field theory.

Prof.
Kostas Skenderis
(University of Amsterdam)

7/22/10, 4:15 PM

12 - Beyond Quantum Field Theory Approaches (including String Theories)

Parallel Session Talk

There has been a lot of interest in recent times in systems with non-relativistic conformal symmetry, such as the Schroedinger symmetry. Such systems appear in condensed matter physics such as, for example, fermions at unitarity. Here we discuss how to set up holography for bulk systems with Schroedinger symmetry.

Dr
Vasilis Niarchos
(University of Crete and Ecole Polytechnique)

7/22/10, 4:45 PM

12 - Beyond Quantum Field Theory Approaches (including String Theories)

Parallel Session Talk

D-branes with a U-shaped geometry, like the D8 flavor branes in the Sakai-Sugimoto model of QCD, are encountered frequently in holographic backgrounds. We argue that the commonly used DBI action is inadequate as an effective field theory description of these branes, and discuss an effective action that incorporates naturally the non-local physics of a complex scalar mode. Our results are...

Dr
James Sparks
(University of Oxford)

7/22/10, 5:06 PM

12 - Beyond Quantum Field Theory Approaches (including String Theories)

Parallel Session Talk

I will summarize recent progress in constructing M-theory/string theory duals to (2+1)-dimensional superconformal field theories.

Dr
Samuel Wallon
(CNRS/LPT Orsay)

7/22/10, 5:27 PM

12 - Beyond Quantum Field Theory Approaches (including String Theories)

Parallel Session Talk

We study the doubly virtual Compton scattering off a spinless target gamma* P -> gamma* P' within the Anti-de Sitter(AdS)/QCD formalism. We find that the general structure allowed by the Lorentz invariance and gauge invariance of the Compton amplitude is not easily reproduced with the standard recipes of the AdS/QCD correspondence. In the soft-photon regime, where the semi-classical...

Bennie Ward
(Baylor University, Waco, TX, USA)

7/22/10, 5:43 PM

12 - Beyond Quantum Field Theory Approaches (including String Theories)

Parallel Session Talk

In Weinberg’s asymptotic safety approach to quantum gravity, one has a finite dimensional critical surface for a UV stable fixed point to generate a theory of quantum gravity with a finite number of physical parameters. The task is to demonstrate how this fixed point behavior actually arises. We argue that, in a recently formulated extension of Feynman’s original formulation of the theory,...