Third Workshop on Nonperturbative Aspects of Gauge Fields and Strings

Jena, February 22 - 24, 2001

Twenty-eight years after the inception of QCD its low-energy features are still not fully understood. The two main problems are the spontaneous breakdown of chiral symmetry and confinement. While the former is reasonably well described by the instanton vacuum, the property of confinement remains somewhat elusive. Nonetheless, the last few years have seen some remarkable progress in this direction. With the work of Seiberg and Witten there is now an exact non-perturbative solution of a strongly coupled gauge theory in four dimensions, though in a supersymmetric setting. This work has leant new support to the old idea of describing the vacuum as a dual superconductor where confinement is due to monopole condensation and a dual Meissner effect. In addition, lattice calculations using (variants of) 't Hooft's maximal abelian gauge fixing find that abelian and monopole fields are the dominant configurations in the path integral (abelian and monopole dominance). It is, however, difficult to confirm these results in a gauge independent way. Depending on the gauge chosen, there are alternative confinement mechanisms (like e.g. vortex percolation). In addition, the relation to the instanton vacuum remains to be further investigated.

Without simplifying assumptions like supersymmetry, it is rather difficult to confirm the lattice results analytically. Already at the kinematical level one has to deal with the issues of gauge fixing ambiguities, the Gribov problem and the like. A theoretical description of the confinement dynamics starting from first principles seems rather hopeless at present. Thus, for the time being, one has to rely on the respectable tradition of model building and effective field theories. One particular candidate of these, the dual Abelian Higgs model, has recently been shown to lead to an effective 4d string theory of confinement.

Remarkably, also from the pure string theory side there is now a route towards confinement via the celebrated AdS/CFT or, more generally, bulk/boundary correspondence. Gravity theories in D+1 dimensions, stemming from the low energy expansion of string theory, are conjectured to be equivalent to a D-dimensional Yang-Mills theory on its boundary. In this way one hopes to gain insight into the strong coupling regime of the respective gauge theory, not accessible to standard perturbation theory. In particular, using effective supergravity models, one can study the large-N sector of gauge theories, Wilson loops, glueballs and even the shape of the flux tube. In order to tie in to more realistic gauge theories such as four-dimensional QCD, it is of interest to study more general gauged supergravity backgrounds.

There is also another recent impact of string theory on standard Yang-Mills theory: string vacua with a nonvanishing B-field have been seen to induce a noncommutative deformation of the space-time structure underlying effective Yang-Mills theories on branes. This has revived older ideas of Connes and others to define and study gauge theories on noncommutative spacetimes. To some extent, such gauge theories may be viewed as regularizations of continuum Yang-Mills theory, providing an alternative to the standard lattice approach.

It thus seems that, after a long period of divergence, gauge field theory, gravity and string theory are again converging towards each other. It is the purpose of the workshop to bring together experts from several ends of the activities described above, allowing for mutual inspiration and lively interaction.

Topics to be Covered

Speakers and Participants

Previous Workshops

Announcements and schedules of the workshops


The airports closest to Jena are Frankfurt/Main and Leipzig. Both do have reasonable train connections with Jena. From Frankfurt airport one has to take a train to Frankfurt/City and continue to Jena with change in Weimar (3-4 hours altogether). Trains will arrive at station ``Jena West''. The train ride from Leipzig takes one hour with arrival at station ``Jena Paradies''. The latter station is still in a somewhat provisoric shape... Train schedules are available via this website.

The workshop will take place at the Abbeanum building, Institute of Theoretical Physics, Friedrich-Schiller University, Jena. If you do not know how to get there please check the city and campus maps. The sessions will start on Thursday, 2:00 p.m., and end on Saturday by 2:00 p.m.

All participants (unless explicitly notified otherwise) will be accommodated at the Hotel am Stadion. It is located at 15 min walking distance from station Jena-Paradies, 25 min from station Jena-West and 30 min from the institute (Abbeanum). There is a tram connection between the hotel and the center of the city via tram lines 4 and 5 (until 8 p.m.) and 35 (after 8 p.m.). The name of the tram stop next to the hotel is ``Sportforum''. For further information concerning public transportation, please check: Those interested in sightseeing, cultural events etc. are advised to visit the

People who would like to participate should register by completing this registration form. There is no deadline and workshop fee. Late applicants, however, may have trouble in getting accommodated.

Organizing Committee

T. Heinzl
T. Strobl
M. Volkov
A. Wipf

Mailing Address:

Theoretisch-Physikalisches Institut
Friedrich-Schiller-Universität Jena
Max-Wien-Platz 1
D-07743 Jena

Phone: 03641/9-47135

last updated February 01, 2001