
Harold C. Steinacker, Ph.D. Lecturer and principal investigator, Universität Wien Fakultät für
Physik




Email: harold.steinacker at univie.ac.at Phone: +43 1 4277 51526 Office: 5th floor 
Research Interests : Theoretical and mathematical physics.
My core interest is the theory of fundamental
interactions. I grew up scientifically in the formal
highenergy theory group at UC Berkeley (advisor: Bruno
Zumino), and my research is aimed towards 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
(which is closely related to the 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. However, the model is viewed here as
fundamental starting point, rather than an effective
description of string theory. The model is not only
extremely simple, it also naturally leads to a quantum
structure of spacetime, which is expected to arise in
quantum gravity.
The basic idea of this approach is to recover
3+1dimensional spacetime as a quantized brane solution of
the matrix model, and the known physics from the
fluctuations on this brane. For YangMills 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 10D bulk (super)gravity, this mechanism doesn't help here (it merely leads to a weak shortrange
interaction on the brane). However, gravity may emerge directly on the
spacetime brane. Once this is understood, its quantization
would be defined naturally by the matrix model.
There is a very promising class of such spacetime
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 recently found cosmological spacetime looks very promising, and a recent
analysis provides strong evidence that gravity indeed
arises. This is work in progress which needs to be
developed further. See also the related
press
release.
Thankfully, this
work has been supported by the Austrian Science Fund FWF.
Without that support, it would not be possible for me to
continue this line of research at the University of Vienna.
Apart from this longterm 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
InSPIRE HEPpreprint
database: search
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
selfintersecting quantum geometries. This is directly relevant
to the abovementioned Matrix Theory, but it also arise within
the framework of ordinary YangMills 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