curriculum vitae

Research Interests : Theoretical and mathematical physics.

My primary research interest is the theory of fundamental interactions, and to help develop a quantum theory of all fundamental interactions including gravity. More specifically, I'm following and developing an approach known as „Matrix Theory“, focusing on the IKKT model (rather than the closely related BFSS model). This can be viewed as a constructive approach to string theory, which avoids the issue of a "landscape" of compactifications and the inherent lack of predictivity. Hence the model is viewed as fundamental starting point, rather than an effective description of string theory. The model is extremely simple, and it naturally leads to a quantum structure of space-time, as expected in quantum gravity.

The basic idea of this approach is to recover 3+1-dimensional space-time as a quantized "brane" solution of the matrix model, and the known physics from the fluctuations on this brane. For Yang-Mills gauge theories, this works in a very nice and convincing way. The main challenge is to recover gravity. While string theory usually relies on the 10-D bulk (super)gravity, this mechanism doesn't help here (it merely leads to a weak short-range interaction on the brane). However, gravity may emerge directly on the space-time brane. Once this is understood, its quantization would be defined naturally by the matrix model.

There is a very promising class of such space-time solutions, dubbed „covariant quantum spaces“. They naturally lead to the spin 2 fluctuations required for gravity, and seem to have just the right properties. In particular, a simple yet reasonable cosmological space-time featuring a Big Bounce was found, and a recent analysis provides strong evidence that gravity indeed arises. This is further corroborated by recovering the linearized Schwarzschild solution.  There is growing evidence that the approach indeed leads to a (at least near-realistic) form of gravity, which - unlike the Einstein Hilbert action - should provide a quantum theory. See also the related press release.   The goal in the next years is to develop this further, and collaborations in this context are very welcome.


This work has been supported by the Austrian Science Fund FWF through various grants. This support was crucial to carry out this line of research at the University of Vienna, and is gratefully acknowledged.

Apart from this long-term project, I'm also interested in other topics in the context of the theory of elementary particles and fundamental interactions, quantum gravity, string theory, noncommutative geometry, random matrix theory, quantum groups, etc.

Selected talks,  providing an introduction & overview of my recent work

Publications

• e-prints at the archive

• InSPIRE HEP-preprint database: search
  

Research Project "Covariant Quantum Spaces, Higher Spin, and Gravity"

supported by the FWF,  P 32086

This project focuses on the recently discovered 3+1-dimensional covariant quantum space-times, which lead to higher-spin gauge theories in the framework of Yang-Mills matrix models. The focus will be on the gravity sector, which arises from spin 2 fluctuation modes on these spaces. This should provide a promising framework for quantum gravity, and we will aim to develop this as far as possible.
Collaborations are welcome!

Members of this research group:  postdoc TBA, Clemens Kerschbaumer (Master's student),  H.S.

(completed) Research Project "Squashed Extra Dimensions in Gauge Theory and Matrix Models"

supported by the FWF,  P 28590

The focus of this project is to explore the physical consequences of fuzzy extra dimensions, notably by certain self-intersecting quantum geometries. This is directly relevant to the above-mentioned Matrix Theory, but it also arise within the framework of ordinary Yang-Mills gauge theory.

This has developed towards „covariant quantum spaces“, which allow to reconcile the notions of covariance and quantum space(time), and provide a promising basis for a higher spin extension of quantum gravity.

Members of this research group:  Marcus Sperling (postdoc), Timon Salar Gutleb (Master's student), Clemens Kerschbaumer (Master's student),  H.S.

(completed) Project "Branes, Gauge Theory and Gravity in Matrix Models" 

supported by the FWF,  P24713,     related press release

(completed) project "Matrix Models, Quantum Spaces, and Gravity" 

supported by FWF,  P21610

Possible topics for a Master's thesis

COST network QSPACE

(I'm member of the management committee & leader of the working group on gravity models)

Training school Quantum Structure of Spacetime and Gravity 2016

Current and recent teaching

• SoSe 2018 VL „Analysis für PhysikerInnen II“, mit Übungen

• WS 2017/18 „Analysis für PhysikerInnen I“, mit Übungen

Lecture notes:

• Lie groups and Lie algebras for physicists
  
  
  

related seminars, conferences

• Workshop Matrix Models for Noncommutative Geometry and String Theory

• Quantum Spacetime 18

• international workshop on "Noncommutative Geometry, Duality and Quantum Gravity"

• Quantum Spacetime 17

• Training school Quantum Structure of Spacetime and Gravity 2016

• Workshop on Noncommutative Field Theory and Gravity , Corfu, September 19 - 26, 2015

useful links

Theoretischen Physik, Universität Wien

Inspire HEP Search