Rethinking Quantum Field Theory

Session

Plenary Session

27 Sept 2016, 14:10

Main Auditorium (DESY Hamburg)

Conveners

Plenary Session

• Gleb Arutyunov

Plenary Session

• Stefan Theisen

Plenary Session

• Stefan Hollands

Plenary Session

• Rutger Boels

Plenary Session

• Albrecht Klemm

Plenary Session

• Stephan Stieberger

Plenary Session

• Karl Jansen

Plenary Session

• Volker Schomerus

111. UV Completion of Some UV Fixed Points

Igor Klebanov

27/09/2016, 14:10

We start by reviewing UV completion of the Gross-Neveu model in dimensions between two and four via the Gross-Neveu-Yukawa model, which is a multi-flavor Yukawa theory. We discuss the operator scaling dimensions and the sphere free energy for these Conformal Field Theories. The case of a single two-component Majorana fermion is special in that the theory appears to flow to a CFT with...

112. The Yang-Mills gradient flow -- a new tool in non-perturbative QFT

Martin Luescher

27/09/2016, 14:50

The Yang-Mills gradient flow provides new insight into the dynamics of non-Abelian gauge theories and has become a widely used tool in lattice QCD. In this talk, the theoretical foundation of the flow is reviewed and some of its applications are briefly described.

113. Numerical Stochastic Perturbation Theory

Francesco Di Renzo

27/09/2016, 15:30

Perturbation theory for lattice regularization of field theory is known to be a quite hard subject and this holds true in particular for lattice gauge theory. In the 90's the numerical implementation of stochastic perturbation theory (NSPT) was introduced. NSPT can not only make perturbative computations on the lattice (in some cases much) easier, but also enable the computation of...

114. C-theorems and Entanglement Entropy

Marina Huerta

27/09/2016, 16:40

A great part of the problem of understanding the structure of the space of quantum field theories (QFT) is arguably reduced to the one of classifying possible critical points. In this picture, the theories with mass scales are obtained by perturbing critical points and following the renormalization group (RG) trajectories. However, interestingly, in the flow not all critical points can be...

115. N=2 SUSY field theories: A window into nonperturbative QFT ?

Joerg Teschner

27/09/2016, 17:20

Considerable progress has been made in the last few years on various N=2 supersymmetric field theories. The progress includes exact results for expectation values of Wilson loop observables and various other quantities. In my talk I will review some of these developments, and try to extract some lessons of general interest for a wider audience with interests in quantum field theory.

117. Quantum moduli spaces and quantum algebras

Vasily Pestun

28/09/2016, 09:10

I will review the gauge theoretical construction of quantum algebras such as q-deformed W-algebras and quantum groups from the geometry of the moduli space of quiver instantons, moduli space of monopoles and moduli space of vacua of N=2 supersymmetric gauge theories.

118. From Yang-Mills Theory to the Veneziano Amplitude

Zohar Komargodsky

28/09/2016, 09:50

We consider weakly-coupled theories of massive higher-spin particles. This class of models includes, for instance, tree-level String Theory and Large-N Yang-Mills theory. The S-matrix in such theories is a meromorphic function obeying unitarity and crossing symmetry. We discuss the unphysical high-energy fixed imaginary angle scattering regime. We expect the amplitude to be universal and...

119. Comments on families of N=2 SCFTs

Kyriakos Papadodimas

28/09/2016, 10:30

I will review some exact results about the coupling constant dependence of the chiral ring in four dimensional N=2 theories.

120. Quantum Simulation of Lattice Gauge Theories

Uwe-Jens Wiese

28/09/2016, 11:40

Besides lattice QCD in particle physics, strongly coupled gauge theories arise, for example, in the condensed matter physics of spin liquids, or in the quantum information theory of Kitaev's toric code, which is a Z(2) lattice gauge theory. Numerical simulations of gauge theories on classical computers, in particular, at high fermion density or in out-of-equilibrium situations, suffer from...

121. A Duality Web in 2 + 1 Dimensions and the Unity of Physics

Nathan Seiberg

28/09/2016, 12:20

Combining insights from different branches of physics we will present a rich set of dualities in 2+1 dimensions

125. Integrability in gauge and string theory

Romuald Janik

29/09/2016, 09:00

In this talk I will give an overview of various developments in integrability within the AdS/CFT correspondence emphasizing novel directions and setups. I will also point out some outstanding questions.

123. Constructing Gravity Theories from Gauge Theories

Henrik Johansson

29/09/2016, 09:40

I will discuss how gravity scattering amplitudes of many different gravitational theories can be obtained from various gauge theories through a double-copy procedure. The basic idea goes back to the old relation between open and closed strings, but I will argue that gravity being the double copy of two gauge theories is a more general notion. I will present new striking examples of gravity...

124. Worldsheet Models in Quantum Field Theory

Yvonne Geyer

29/09/2016, 10:20

The last years have seen remarkable progress in understanding the scattering amplitudes of massless particles in arbitrary dimension. They not only exhibit a simplicity completely obscured by the Feynman Diagram approach, but also a structure strikingly reminiscent of the worldsheet models describing string theory. After reviewing the key developments, I will discuss the worldsheet models,...

122. Quantum Field Theory Without Quantum Fields: Scattering Amplitudes as Binary Code

Nima Arkani-Hamed

29/09/2016, 11:30

126. Tensor Networks and their use for Lattice Gauge Theories

Mari Carmen Banuls

29/09/2016, 12:10

The term Tensor Network States (TNS) has become a common one in the context of numerical studies of quantum many-body problems. It refers to a number of families that represent different ansatzes for the efficient description of the state of a quantum many-body system. The first of these families, Matrix Product States (MPS), lies at the basis of Density Matrix Renormalization Group methods,...

127. Locality and Quantum Physics: the Algebraic Approach to Quantum Field Theory

Klaus Fredenhagen

30/09/2016, 09:00

The locality of fundamental interactions and the nonlocal character of quantum correlations are reconciled in the framework of algebraic quantum field theory. The theory is based on the concept of local fields which are mathematically characterized as natural tranformations between suitable functors. The framework covers quantum field theories on generic Lorentzian manifolds including also...

128. Conformal bootstrap overview

Balt Van Rees

30/09/2016, 09:40

In this talk we will give an overview of recent results obtained from the bootstrap approach to CFTs. We will discuss both analytical and numerical results, including for supersymmetric theories. We identify several promising directions for further research

129. Unitarity and positivity constraints for CFT at large and central charge

Luis Fernando Alday

30/09/2016, 10:20

130. RG Inequalities in Diverse Dimensions

Thomas Dumitrescu

30/09/2016, 11:30

131. Restriction on the initial state for the absence of IR effect in single field inflation

Takahiro Tanaka

30/09/2016, 12:10

It has been claimed that the super Hubble modes generated during inflation can make loop corrections diverge. Even if we introduce an infrared (IR) cutoff at a comoving scale as an ad hoc but a practical way for the regularization, we encounter the secular growth, which may lead to the breakdown of perturbative expansion for a　sufficiently long lasting inflation. We show that the IR...