Conveners
Parallel Session Strings: Strings / Mathematical Physics I
- Craig Lawrie
- Markus Dierigl (LMU)
Parallel Session Strings: Strings / Mathematical Physics II
- Markus Dierigl (LMU)
- Craig Lawrie
Parallel Session Strings: Strings / Mathematical Physics III
- Markus Dierigl (LMU)
- Craig Lawrie
Parallel Session Strings: Strings / Mathematical Physics IV
- Craig Lawrie
- Markus Dierigl (LMU)
The Higgs branches of the world-volume theories for multiple M5 branes on an $A_k$ or $D_k$-type ALE space are known to host a variety of fascinating properties, such as the small E 8 instanton transition or the discrete gauging phenomena. This setup can be further enriched by the inclusion of boundary conditions, which take the form of $SU(k)$ or $SO(2k)$ partitions, respectively. Unlike the...
Yang-Mills theory is at the heart of theoretical physics, but even classical analytic solutions for its equations are in general very hard to be obtained. This makes algebraic and geometric methods to construct such solutions especially important in this context. In this seminar, we will briefly see how equivariant Ansatz and foliation of the Minkowski space via non-compact cosets can be used...
Topological defects have long been known to encode symmetries and
dualities between physical systems. In this talk I will show, at the level of the target space, how defects can be used to study a generalized notion of T-duality, known as Poisson-Lie T-duality. This defect in turn provides us with a proposed kernel for the Fourier-Mukai transform implementing Poisson-Lie T-duality on the...
An important part of information in evaluating Feynman integrals is the symbol letters (or alphabet) of the integral. This information makes it possible to write the integral as an ansatz of multiple polylogaritms with the letters as arguments. Moreover, the zeros of the letters correspond to the dynamical (Landau) singularities of the integral. In this work we are calculating the dynamical...
Conformal Field Theories (CFTs), which appear as critical points of an array of physical theories, can be studied nonperturbatively by means of the conformal bootstrap. Recent advancements in especially the numerical bootstrap made it possible to obtain extremely precise results for critical exponents in various CFTs. CFTs can be generalized by adding extended objects (defects), which break...
We study four-point functions of spinning operators in the flavor current multiplet in four dimensional N = 2 SCFTs, using superspace techniques. In particular we explicitly construct the differential operators relating the different components of the super-correlator. As a byproduct of our analysis, we report the computation of the four-point amplitudes of gluons in bosonic Yang-Mills...
In this talk I will argue that "black shells", which are spherical brane bubbles enclosing AdS spacetime can mimic black holes. Such bubbles of AdS are generically unstable, but can be stabilized at a finite radius just outside the would-be horizon of the object by dissolved D0 branes and a gas of open strings.These bubbles can arise from brane polarization effects and are natural to expect...
4D $\mathcal{N}=2$ SCFTs obtained from orbifolding $\mathcal{N}=4$ SYM and then performing a marginal deformation exhibit hidden symmetries. Namely, the orbifolding procedure breaks down some actions of the generators coming from $\mathcal{N}=4$. However, by employing a non-trivial co-product involving a (Drinfeld) twist, the actions of the broken generators can be ``restored'' as generators...
The Cobordism Conjecture postulates that the cobordism classes in a consistent theory of quantum gravity should be trivial, possibly predicting new stringy defects. In this light, I will discuss the Dynamical Cobordism induced by the backreaction of a 9-dimensional non-supersymmetric, positive tension domain wall in string theory. Breaking the cobordism symmetry requires a 7-brane defect...
I will discuss the critical physics of a class of disordered (impure) quantum field theories, called random field models. An interesting example comes from 'branched polymers' whose critical properties are described by the random field phi^3 model. Parisi and Sourlas conjectured nearly 40 years ago that these models have a critical point characterized by an emergent supersymmetry and a...
The eikonal exponentiation provides a natural strategy to calculate classical gravitational observables directly from the loop-expansion of gravity amplitudes. In this talk I will discuss how the eikonal can be applied to obtain the deflection angle for the collision of two non-spinning black holes. The inclusion of radiation-reaction effects results in an expression with a smooth behavior at...
The study of spin chains which capture the spectral problem of N=2 SCFTs in the planar limit can shed light on the integrability of 4d gauge theories with less supersymmetry. I investigate the SU(2) subsector of an orbifold daughter of N=4 SYM by using coordinate Bethe Ansatz method. Exact results of the coordinate Bethe ansatz hints an underlying structure such that S-matrix coefficients...
Recently, the correspondence between an ensemble average over two—dimensional Narain conformal field theories and an “exotic” bulk theory of gravity was established by Maloney and Witten and by N. Afkhami-Jeddi, H. Cohn, T. Hartman, and A. Tajdini. This has been generalized to specific torodial orbifolds by N. Benjamin, C. A. Keller, H. Ooguri, and I. G. Zadeh. We test this correspondence...
The "hexagonalization" procedure arose in the context of integrability in the AdS/CFT correspondence, in order to compute correlation functions in planar N = 4 SYM. This approach, formalized by Basso, Vieira and Komatsu in 2015 is based upon a cutting procedure of the closed string worldsheet that permits to obtain two building blocks that can be "bootstrapped" using the power of the...
Supersymmetric conformal field theories have gained huge renewed interest, especially due to the Maldacena conjecture relating N = 4 supersymmetric Yang-Mills theory to type IIB string theory on AdS5 × S5. To gain a better understanding of
these theories it is important to study the implications of the N = 4 superconformal
symmetry in 4 dimensions, PSU(2,2|4), on the observables. In this...
I will discuss vacua of Heterotic toroidal orbifolds using effective theories consisting of an overall Kahler modulus, the dilaton, and non-perturbative corrections to both the superpotential and Kahler potential that respect target space modular invariance. I will prove a de Sitter no-go theorem for a class of vacua and thereby substantiate a previous conjecture. I will illustrate a loophole...
I will review the types of special functions appearing in Feynman integrals and string amplitudes, and show how multiple polylogarithms (MPLs) and elliptic multiple polylogarithms (eMPLs) appear in both contexts. Next, I will present new work on elliptic modular graph forms (eMGFs), which appear in closed genus-one string amplitudes. These functions can be loosely thought of as single-valued...
The space of two dimensional quantum field theories can be probed by considering renormalization group flows, whose fixed points are either conformal field theories or trivial theories. Among the conformal field theories there are some models that are unitary (i.e. the inner product in the Hilbert space is non-negative) and some others that are not unitary; although unitarity is usually...
In short, I shows that Liouville Field Theory (LFT) is the effective field theory of a theory with larger non-compact symmetry group which undergoes a novel mechanism of spontaneous symmetry breaking. The famous, but ill-understood, reflection amplitude of LFT acquires a natural explanation in this context and can be derived from a purely representation theoretic viewpoint. Furthermore, this...
