This week


All N=4 conformal supergravities

Regular Seminar Franz Ciceri (AEI Potsdam)

15:00 QMW
room G O Jones 610

Supersymmetric extensions of conformal gravity have been known for a long time. In four dimensions, N=4 conformal supergravity is the maximally supersymmetric theory of this type. Although its field representation and the non-linear transformations rules were derived more than 30 years ago, no invariant action had been constructed so far. We present the most general class of actions which turns out to be characterised by a holomorphic function. This deviates from the non-maximally supersymmetric cases where the action is unique. Meanwhile, elaborate loop computations have indicated that N=4 Poincare supergravity diverges at four loops, and the divergence is believed to be related to the presence of a potential one-loop anomaly in the duality symmetry of the theory. We argue that one of the constructed conformal actions, after gauge fixing the conformal symmetries and carefully eliminating auxiliary fields, can be used as a finite supersymmetric counterterm that cancels the anomalous contribution of the one-loop graphs in the Poincare theory.


Little Strings, Long Strings, and Fuzzballs

Regular Seminar Emil Martinec (Chicago)

14:00 IC
room H503

The microstate structure of AdS3 black holes involves stringy ingredients, yet quantitative control over these ingredients in a regime where the state being described approximates a black hole has been elusive. This talk will show how 2d worldsheet current algebra provides a tool to describe the stringy objects that govern the black hole phase transition in AdS3 and linear dilaton backgrounds, providing a bridge between the entropy-carrying degrees of freedom of the dual non-gravitational theory (little strings or long strings) and their conjectured gravitational dual, the fuzzball.


Effective Field Theories of Post-Newtonian Gravity

Regular Seminar Michele Levi (IPhT Saclay)

14:00 QMW
room G O Jones 610

This talk presents the progress made in my research via the introduction of effective field theories (EFTs) into post-Newtonian (PN) gravity. These have been put forward in the context of gravitational waves (GWs) from the compact binary inspiral. The setup and the strategy of a multi-stage EFT framework, which is deployed for the PN binary inspiral problem, is outlined. I then present in more detail the study of two effective theories at the intermediate scales of the problem. First, the EFT for a single rotating compact object is considered, from which I proceed to the EFT of a compact binary system, viewed as a composite particle with internal binding interactions. I conclude with the prospects of building on the field, and using further modern field theory insights and tools, to address the study of GWs, as well as to expand our fundamental understanding of QFTs and gravity theories at all scales.


20.05.2019 - 22.05.2019

Hamilton School on Mathematical Physics

2019-05-20 - 2019-05-22 at TRINITY COLLEGE DUBLIN


The study of gauge theory and conformal field theory have lead to remarkable advancements in theoretical physics. The first Hamilton school on Mathematical Physics will be held at Trinity College Dublin, Ireland, from the 20th to the 22nd of May, and will focus on modern advancements in gauge theory and conformal field theory, with a particular eye towards providing an interdisciplinary treatment of different subfields in these topics.

The ability to combine ideas from different subfields continues to play an increasingly large role in theoretical physics. For example, modern methods in amplitudes include tools that range from Hopf algebras, to modular forms, to the appearance and use of Yangian symmetries. On the other side of the spectrum, generating functions of topological invariants of various moduli spaces that are computed by gauge and string theoretic methods are also expressed in terms of modular forms and their generalizations. Furthermore, theories like the Seiberg-Witten gauge theory provide another route to integrability. It seems therefore that good parallel understanding of aspects of gauge theory and conformal field theory, integrability and modular forms could be of crucial importance for in the future.